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LTE协议36300-990


3GPP TS 36.300 V9.9.0 (2011-12)
Technical Specification

3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 9)

The present document has been developed within the 3rd Generation Partnership Project (3GPP TM) and may be further elaborated for the purposes of 3GPP. The present document has not been subject to any approval process by the 3GPP Organizational Partners and shall not be implemented. This Specification is provided for future development work within 3GPP only. The Organizational Partners accept no liability for any use of this Specification. Specifications and reports for implementation of the 3GPP TM system should be obtained via the 3GPP Organizational Partners' Publications Offices.

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3GPP TS 36.300 V9.9.0 (2011-12)

Keywords
UMTS, stage 2, radio, architecture

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3GPP support office address
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Internet
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Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media.
? 2011, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC). All rights reserved. UMTS? is a Trade Mark of ETSI registered for the benefit of its members 3GPP? is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners LTE? is a Trade Mark of ETSI currently being registered for the benefit of its Members and of the 3GPP Organizational Partners GSM? and the GSM logo are registered and owned by the GSM Association

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Contents
Foreword .................................................................................................................................................... 11 1 2 3
3.1 3.2

Scope ................................................................................................................................................ 12 References ........................................................................................................................................ 12 Definitions, symbols and abbreviations ............................................................................................. 13
Definitions ................................................................................................................................................. 13 Abbreviations............................................................................................................................................. 14

4
4.1 4.2 4.2.1 4.2.2 4.3 4.3.1 4.3.2 4.4 4.5 4.6 4.6.1 4.6.2 4.6.3 4.6.3.1 4.6.3.2 4.6.4

Overall architecture........................................................................................................................... 17
Functional Split .......................................................................................................................................... 17 Interfaces ................................................................................................................................................... 19 S1 Interface .......................................................................................................................................... 19 X2 Interface.......................................................................................................................................... 19 Radio Protocol architecture ........................................................................................................................ 19 User plane ............................................................................................................................................ 19 Control plane ........................................................................................................................................ 20 Synchronization ......................................................................................................................................... 21 IP fragmentation ........................................................................................................................................ 21 Support of HeNBs ...................................................................................................................................... 21 Architecture.......................................................................................................................................... 21 Functional Split .................................................................................................................................... 22 Interfaces .............................................................................................................................................. 23 Protocol Stack for S1 User Plane ..................................................................................................... 23 Protocol Stacks for S1 Control Plane ............................................................................................... 24 Void ..................................................................................................................................................... 25

5
5.1 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 5.1.7 5.1.7.1 5.1.7.2 5.1.7.3 5.1.8 5.2 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.2.6 5.2.7 5.2.7.1 5.2.7.2 5.2.7.3 5.3 5.3.1 5.4 5.4.1 5.4.2

Physical Layer for E-UTRA .............................................................................................................. 25
Downlink Transmission Scheme................................................................................................................. 27 Basic transmission scheme based on OFDM.......................................................................................... 27 Physical-layer processing ...................................................................................................................... 27 Physical downlink control channel ........................................................................................................ 28 Downlink Reference signal ................................................................................................................... 28 Downlink multi-antenna transmission ................................................................................................... 28 MBSFN transmission ............................................................................................................................ 29 Physical layer procedure ....................................................................................................................... 29 Link adaptation ............................................................................................................................... 29 Power Control ................................................................................................................................. 29 Cell search ...................................................................................................................................... 29 Physical layer measurements definition ................................................................................................. 29 Uplink Transmission Scheme ..................................................................................................................... 30 Basic transmission scheme .................................................................................................................... 30 Physical-layer processing ...................................................................................................................... 30 Physical uplink control channel ............................................................................................................. 30 Uplink Reference signal ........................................................................................................................ 31 Random access preamble ...................................................................................................................... 31 Uplink multi-antenna transmission ........................................................................................................ 31 Physical channel procedure ................................................................................................................... 31 Link adaptation ............................................................................................................................... 31 Uplink Power control ...................................................................................................................... 31 Uplink timing control ...................................................................................................................... 31 Transport Channels .................................................................................................................................... 32 Mapping between transport channels and physical channels................................................................... 33 E-UTRA physical layer model .................................................................................................................... 33 Void ..................................................................................................................................................... 33 Void ..................................................................................................................................................... 33

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6
6.1 6.1.1 6.1.2 6.1.2.1 6.1.2.2 6.1.3 6.1.3.1 6.1.3.2 6.2 6.2.1 6.2.2 6.3 6.3.1 6.3.2 6.4

Layer 2 ............................................................................................................................................. 33
MAC Sublayer ........................................................................................................................................... 35 Services and Functions.......................................................................................................................... 35 Logical Channels .................................................................................................................................. 35 Control Channels............................................................................................................................. 35 Traffic Channels.............................................................................................................................. 36 Mapping between logical channels and transport channels ..................................................................... 36 Mapping in Uplink .......................................................................................................................... 36 Mapping in Downlink...................................................................................................................... 36 RLC Sublayer ............................................................................................................................................ 37 Services and Functions.......................................................................................................................... 37 PDU Structure ...................................................................................................................................... 38 PDCP Sublayer .......................................................................................................................................... 38 Services and Functions.......................................................................................................................... 38 PDU Structure ...................................................................................................................................... 39 Void .......................................................................................................................................................... 39

7
7.1 7.2 7.3 7.4 7.5

RRC ................................................................................................................................................. 39
Services and Functions ............................................................................................................................... 39 RRC protocol states & state transitions ....................................................................................................... 40 Transport of NAS messages ....................................................................................................................... 40 System Information .................................................................................................................................... 41 Void .......................................................................................................................................................... 42

8
8.1 8.2

E-UTRAN identities ......................................................................................................................... 42
E-UTRAN related UE identities ................................................................................................................. 42 Network entity related Identities ................................................................................................................. 42

9
9.1 9.2 9.3

ARQ and HARQ ............................................................................................................................... 43
HARQ principles ....................................................................................................................................... 43 ARQ principles .......................................................................................................................................... 44 Void .......................................................................................................................................................... 44

10

Mobility ............................................................................................................................................ 44

10.1 Intra E-UTRAN ......................................................................................................................................... 44 10.1.1 Mobility Management in ECM-IDLE .................................................................................................... 45 10.1.1.1 Cell selection................................................................................................................................... 45 10.1.1.2 Cell reselection................................................................................................................................ 45 10.1.1.3 Void ................................................................................................................................................ 46 10.1.1.4 Void ................................................................................................................................................ 46 10.1.1.5 Void ................................................................................................................................................ 46 10.1.2 Mobility Management in ECM-CONNECTED ..................................................................................... 46 10.1.2.1 Handover ........................................................................................................................................ 46 10.1.2.1.1 C-plane handling........................................................................................................................ 47 10.1.2.1.2 U-plane handling........................................................................................................................ 50 10.1.2.2 Path Switch ..................................................................................................................................... 51 10.1.2.3 Data forwarding .............................................................................................................................. 51 10.1.2.3.1 For RLC-AM DRBs ................................................................................................................... 51 10.1.2.3.2 For RLC-UM DRBs ................................................................................................................... 52 10.1.2.3.3 SRB handling............................................................................................................................. 52 10.1.2.4 Void ................................................................................................................................................ 53 10.1.2.5 Void ................................................................................................................................................ 53 10.1.2.6 Void ................................................................................................................................................ 53 10.1.2.7 Timing Advance .............................................................................................................................. 53 10.1.3 Measurements....................................................................................................................................... 53 10.1.3.1 Intra-frequency neighbour (cell) measurements ................................................................................ 54 10.1.3.2 Inter-frequency neighbour (cell) measurements ................................................................................ 54 10.1.4 Paging and C-plane establishment ......................................................................................................... 55 10.1.5 Random Access Procedure .................................................................................................................... 55 10.1.5.1 Contention based random access procedure...................................................................................... 55 10.1.5.2 Non-contention based random access procedure ............................................................................... 57 10.1.5.3 Interaction model between L1 and L2/3 for Random Access Procedure ............................................ 58 10.1.6 Radio Link Failure ................................................................................................................................ 58

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10.1.7 Radio Access Network Sharing ............................................................................................................. 59 10.1.8 Handling of Roaming and Area Restrictions for UEs in ECM-CONNECTED ........................................ 60 10.2 Inter RAT .................................................................................................................................................. 60 10.2.1 Cell reselection ..................................................................................................................................... 60 10.2.2 Handover .............................................................................................................................................. 61 10.2.2a Inter-RAT cell change order to GERAN with NACC............................................................................. 61 10.2.2b Inter-RAT handovers from E-UTRAN .................................................................................................. 61 10.2.2b.1 Data forwarding .............................................................................................................................. 61 10.2.2b.1.1 For RLC-AM bearers ................................................................................................................. 61 10.2.2b.1.2 For RLC-UM bearers ................................................................................................................. 62 10.2.3 Measurements....................................................................................................................................... 62 10.2.3.1 Inter-RAT handovers from E-UTRAN ............................................................................................. 62 10.2.3.2 Inter-RAT handovers to E-UTRAN ................................................................................................. 62 10.2.3.3 Inter-RAT cell reselection from E-UTRAN ...................................................................................... 63 10.2.3.4 Limiting measurement load at UE .................................................................................................... 63 10.2.4 Network Aspects .................................................................................................................................. 63 10.2.5 CS fallback ........................................................................................................................................... 63 10.3 Mobility between E-UTRAN and Non-3GPP radio technologies ................................................................. 64 10.3.1 UE Capability Configuration................................................................................................................. 64 10.3.2 Mobility between E-UTRAN and cdma2000 network ............................................................................ 64 10.3.2.1 Tunnelling of cdma2000 Messages over E-UTRAN between UE and cdma2000 Access Nodes ........ 65 10.3.2.2 Mobility between E-UTRAN and HRPD ......................................................................................... 66 10.3.2.2.1 Mobility from E-UTRAN to HRPD ............................................................................................ 66 10.3.2.2.1.1 HRPD System Information Transmission in E-UTRAN ........................................................ 66 10.3.2.2.1.2 Measuring HRPD from E-UTRAN ....................................................................................... 66 10.3.2.2.1.2.1 Idle Mode Measurement Control ..................................................................................... 66 10.3.2.2.1.2.2 Active Mode Measurement Control ................................................................................. 66 10.3.2.2.1.2.3 Active Mode Measurement .............................................................................................. 66 10.3.2.2.1.3 Pre-registration to HRPD Procedure...................................................................................... 66 10.3.2.2.1.4 E-UTRAN to HRPD Cell Re-selection .................................................................................. 67 10.3.2.2.1.5 E-UTRAN to HRPD Handover ............................................................................................. 67 10.3.2.2.2 Mobility from HRPD to E-UTRAN ............................................................................................ 67 10.3.2.3 Mobility between E-UTRAN and cdma2000 1xRTT ........................................................................ 67 10.3.2.3.1 Mobility from E-UTRAN to cdma2000 1xRTT .......................................................................... 67 10.3.2.3.1.1 cdma2000 1xRTT System Information Transmission in E-UTRAN ....................................... 67 10.3.2.3.1.2 Measuring cdma2000 1xRTT from E-UTRAN ...................................................................... 67 10.3.2.3.1.2.1 Idle Mode Measurement Control ........................................................................................... 67 10.3.2.3.1.2.2 Active Mode Measurement Control ...................................................................................... 68 10.3.2.3.1.2.3 Active Mode Measurement ................................................................................................... 68 10.3.2.3.1.3 E-UTRAN to cdma2000 1xRTT Cell Re-selection ................................................................ 68 10.3.2.3.1.4 E-UTRAN to cdma2000 1xRTT Handover ............................................................................ 68 10.3.2.3.2 Mobility from cdma2000 1xRTT to E-UTRAN .......................................................................... 68 10.3.2.3.3 1xRTT CS Fallback ................................................................................................................... 68 10.4 Area Restrictions........................................................................................................................................ 70 10.5 Mobility to and from CSG and Hybrid cells ................................................................................................ 71 10.5.0 Principles for idle-mode mobility with CSG cells .................................................................................. 71 10.5.0.1 Intra-frequency mobility .................................................................................................................. 71 10.5.0.2 Inter-frequency mobility .................................................................................................................. 71 10.5.0.3 Inter-RAT Mobility ......................................................................................................................... 71 10.5.1 Inbound mobility to CSG cells .............................................................................................................. 71 10.5.1.1 RRC_IDLE ..................................................................................................................................... 71 10.5.1.2 RRC_CONNECTED ....................................................................................................................... 71 10.5.2 Outbound mobility from CSG cells ....................................................................................................... 73 10.5.2.1 RRC_IDLE ..................................................................................................................................... 73 10.5.2.2 RRC_CONNECTED ....................................................................................................................... 74 10.6 Measurement Model................................................................................................................................... 74 10.7 Hybrid Cells............................................................................................................................................... 74 10.7.1 RRC_IDLE .......................................................................................................................................... 74 10.7.2 RRC_CONNECTED ........................................................................................................................... 75 10.7.2.1 Inbound Mobility ............................................................................................................................ 75 10.7.2.2 Outbound Mobility .......................................................................................................................... 75

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11.1 11.1.1 11.1.2 11.2 11.3 11.4 11.4.1 11.4.2 11.5 11.6

Scheduling and Rate Control ............................................................................................................. 75
Basic Scheduler Operation ......................................................................................................................... 75 Downlink Scheduling ........................................................................................................................... 75 Uplink Scheduling ................................................................................................................................ 76 Void .......................................................................................................................................................... 76 Measurements to Support Scheduler Operation ........................................................................................... 76 Rate Control of GBR and UE-AMBR ......................................................................................................... 76 Downlink ............................................................................................................................................. 76 Uplink .................................................................................................................................................. 76 CQI reporting for Scheduling ..................................................................................................................... 77 Explicit Congestion Notification................................................................................................................. 77

12 13
13.1 13.2 13.3

DRX in RRC_CONNECTED ........................................................................................................... 77 QoS .................................................................................................................................................. 79
Bearer service architecture ......................................................................................................................... 79 QoS parameters.......................................................................................................................................... 80 QoS support in Hybrid Cells....................................................................................................................... 80

14
14.1 14.2 14.3 14.3.1 14.3.2 14.3.3 14.4 14.5

Security ............................................................................................................................................ 81
Overview and Principles............................................................................................................................. 81 Security termination points ......................................................................................................................... 83 State Transitions and Mobility .................................................................................................................... 83 RRC_IDLE to RRC_CONNECTED ..................................................................................................... 83 RRC_CONNECTED to RRC_IDLE ..................................................................................................... 83 Intra E-UTRAN Mobility...................................................................................................................... 83 AS Key Change in RRC_CONNECTED .................................................................................................... 84 Security Interworking................................................................................................................................. 84

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MBMS.............................................................................................................................................. 84
General ...................................................................................................................................................... 85 E-MBMS Logical Architecture ............................................................................................................. 85 E-MBMS User Plane Protocol Architecture........................................................................................... 87 E-MBMS Control Plane Protocol Architecture ...................................................................................... 87 MBMS Cells .............................................................................................................................................. 88 MBMS-dedicated cell ........................................................................................................................... 88 MBMS/Unicast-mixed cell.................................................................................................................... 88 MBMS Transmission ................................................................................................................................. 88 General................................................................................................................................................. 88 Single-cell transmission ........................................................................................................................ 88 Multi-cell transmission ......................................................................................................................... 88 MBMS Reception States ....................................................................................................................... 90 MCCH Structure................................................................................................................................... 90 MBMS signalling on BCCH ................................................................................................................. 91 MBMS User Data flow synchronisation ................................................................................................ 91 Synchronisation of MCCH Update Signalling via M2............................................................................ 92 IP Multicast Distribution ....................................................................................................................... 92 Service Continuity ..................................................................................................................................... 92 Network sharing......................................................................................................................................... 93 Network Functions for Support of Multiplexing.......................................................................................... 93 Procedures ................................................................................................................................................. 93 Procedures for Broadcast mode ............................................................................................................. 93 Session Start procedure.................................................................................................................... 93 Session Stop procedure .................................................................................................................... 94 M1 Interface .............................................................................................................................................. 95 M1 User Plane ...................................................................................................................................... 95 M2 Interface .............................................................................................................................................. 96 M2 Control Plane ................................................................................................................................. 96 M2 Interface Functions ......................................................................................................................... 97 General ........................................................................................................................................... 97 MBMS Session Handling Function .................................................................................................. 97 MBMS Scheduling Information Provision Function ......................................................................... 97 M2 Interface Management Function ................................................................................................ 97

15.1 15.1.1 15.1.2 15.1.3 15.2 15.2.1 15.2.2 15.3 15.3.1 15.3.2 15.3.3 15.3.4 15.3.5 15.3.6 15.3.7 15.3.8 15.3.9 15.4 15.5 15.6 15.7 15.7.1 15.7.1.1 15.7.1.2 15.7a 15.7a.1 15.8 15.8.1 15.8.2 15.8.2.1 15.8.2.2 15.8.2.3 15.8.2.4

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15.8.2.5 M2 Configuration Function ............................................................................................................. 97 15.8.3 M2 Interface Signalling Procedures ....................................................................................................... 97 15.8.3.1 General ........................................................................................................................................... 97 15.8.3.2 MBMS Session signalling procedure ............................................................................................... 98 15.8.3.3 MBMS Scheduling Information procedure ....................................................................................... 98 15.8.3.4 M2 Interface Management procedures ............................................................................................. 98 15.8.3.4.1 Reset procedure ......................................................................................................................... 98 15.8.3.4.2 Error Indication procedure.......................................................................................................... 98 15.8.3.5 M2 Configuration procedures .......................................................................................................... 98 15.8.3.5.1 M2 Setup procedure ................................................................................................................... 98 15.8.3.5.2 eNB Configuration Update procedure ......................................................................................... 98 15.8.3.5.3 MCE Configuration Update procedure........................................................................................ 98 15.9 M3 Interface .............................................................................................................................................. 98 15.9.1 M3 Control Plane ................................................................................................................................. 98 15.9.2 M3 Interface Functions ......................................................................................................................... 99 15.9.2.1 General ........................................................................................................................................... 99 15.9.2.2 MBMS Session Handling Function .................................................................................................. 99 15.9.2.3 M3 Interface Management Function ................................................................................................ 99 15.9.3 M3 Interface Signalling Procedures ..................................................................................................... 100 15.9.3.1 General ......................................................................................................................................... 100 15.9.3.2 MBMS Session signalling procedure ............................................................................................. 100 15.9.3.3 M3 Interface Management procedures ........................................................................................... 100 15.9.3.3.1 Reset procedure ....................................................................................................................... 100 15.9.3.3.2 Error Indication procedure........................................................................................................ 100

16

Radio Resource Management aspects .............................................................................................. 100

16.1 RRM functions......................................................................................................................................... 100 16.1.1 Radio Bearer Control (RBC) ............................................................................................................... 100 16.1.2 Radio Admission Control (RAC) ........................................................................................................ 101 16.1.3 Connection Mobility Control (CMC)................................................................................................... 101 16.1.4 Dynamic Resource Allocation (DRA) - Packet Scheduling (PS) .......................................................... 101 16.1.5 Inter-cell Interference Coordination (ICIC).......................................................................................... 101 16.1.6 Load Balancing (LB) .......................................................................................................................... 101 16.1.7 Inter-RAT Radio Resource Management ............................................................................................. 101 16.1.8 Subscriber Profile ID for RAT/Frequency Priority ............................................................................... 102 16.2 RRM architecture ..................................................................................................................................... 102 16.2.1 Centralised Handling of certain RRM Functions.................................................................................. 102 16.2.2 De-Centralised RRM .......................................................................................................................... 102 16.2.2.1 UE History Information ................................................................................................................. 102 16.2.3 Load balancing control........................................................................................................................ 102

17
17.1

RF aspects ...................................................................................................................................... 102
Spectrum deployments ............................................................................................................................. 102

18 19

UE capabilities ................................................................................................................................ 102 S1 Interface .................................................................................................................................... 104

19.1 S1 User plane ........................................................................................................................................... 104 19.2 S1 Control Plane ...................................................................................................................................... 104 19.2.1 S1 Interface Functions ........................................................................................................................ 105 19.2.1.1 S1 Paging function ........................................................................................................................ 105 19.2.1.2 S1 UE Context Management function ............................................................................................ 106 19.2.1.3 Initial Context Setup Function ....................................................................................................... 106 19.2.1.3a UE Context Modification Function ................................................................................................ 106 19.2.1.4 Mobility Functions for UEs in ECM-CONNECTED ...................................................................... 106 19.2.1.4.1 Intra-LTE Handover ................................................................................................................. 106 19.2.1.4.2 Inter-3GPP-RAT Handover ..................................................................................................... 106 19.2.1.5 E-RAB Service Management function ........................................................................................... 106 19.2.1.6 NAS Signalling Transport function ................................................................................................ 106 19.2.1.7 NAS Node Selection Function (NNSF) ......................................................................................... 106 19.2.1.8 S1-interface management functions ............................................................................................... 107 19.2.1.9 MME Load balancing Function ..................................................................................................... 107 19.2.1.10 Location Reporting Function ......................................................................................................... 107

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19.2.1.11 19.2.1.12 19.2.1.13 19.2.1.14 19.2.1.15 19.2.1.16 19.2.1.17 19.2.2 19.2.2.1 19.2.2.2 19.2.2.2.1 19.2.2.2.2 19.2.2.3 19.2.2.3a 19.2.2.4 19.2.2.4.1 19.2.2.4.2 19.2.2.4.3 19.2.2.4.4 19.2.2.5 19.2.2.5.1 19.2.2.5.2 19.2.2.5.3 19.2.2.5.4 19.2.2.5.5 19.2.2.5.6 19.2.2.5.7 19.2.2.5.8 19.2.2.6 19.2.2.7 19.2.2.7.1 19.2.2.7.1a 19.2.2.7.1b 19.2.2.7.2 19.2.2.7.2a 19.2.2.7.2b 19.2.2.8 19.2.2.9 19.2.2.9a 19.2.2.10 19.2.2.10a 19.2.2.11 19.2.2.11.1 19.2.2.11.2 19.2.2.11.3 19.2.2.12 19.2.2.12.1 19.2.2.12.2 19.2.2.13 19.2.2.14 19.2.2.15 19.2.2.16 19.2.2.16.1 19.2.2.16.2 19.2.2.17 19.2.2.18 19.2.2.18.1 19.2.2.18.2 19.2.2.18.3 19.2.2.18.4 19.2.2.19 19.2.2.19.1

Warning Message Transmission function ....................................................................................... 107 Overload Function ......................................................................................................................... 107 RAN Information Management Function ....................................................................................... 107 S1 CDMA2000 Tunnelling function .............................................................................................. 107 Configuration Transfer Function .................................................................................................... 107 LPPa Signalling Transport function ............................................................................................... 107 Trace Function .............................................................................................................................. 108 S1 Interface Signalling Procedures ...................................................................................................... 108 Paging procedure........................................................................................................................... 109 S1 UE Context Release procedure.................................................................................................. 110 S1 UE Context Release (EPC triggered) ................................................................................... 110 S1 UE Context Release Request (eNB triggered) ...................................................................... 110 Initial Context Setup procedure...................................................................................................... 111 UE Context Modification procedure .............................................................................................. 111 E-RAB signalling procedures ........................................................................................................ 112 E-RAB Setup procedure ........................................................................................................... 112 E-RAB Modification procedure ................................................................................................ 113 E-RAB Release procedure ........................................................................................................ 114 E-RAB Release Indication procedure ....................................................................................... 115 Handover signalling procedures ..................................................................................................... 115 Handover Preparation procedure .............................................................................................. 115 Handover Resource Allocation procedure ................................................................................. 116 Handover Notification procedure.............................................................................................. 116 Handover Cancellation ............................................................................................................. 117 Path Switch procedure.............................................................................................................. 117 Message sequence diagrams ..................................................................................................... 118 eNB Status Transfer procedure ................................................................................................. 125 MME Status Transfer procedure ............................................................................................... 126 NAS transport procedures .............................................................................................................. 126 S1 interface Management procedures ............................................................................................. 128 Reset procedure ....................................................................................................................... 128 eNB initiated Reset procedure .................................................................................................. 128 MME initiated Reset procedure ................................................................................................ 128 Error Indication functions and procedures................................................................................ 129 eNB initiated error indication ................................................................................................... 129 MME initiated error indication ................................................................................................. 129 S1 Setup procedure........................................................................................................................ 130 eNB Configuration Update procedure ............................................................................................ 130 eNB Configuration Transfer procedure .......................................................................................... 131 MME Configuration Update procedure .......................................................................................... 131 MME Configuration Transfer procedure ........................................................................................ 132 Location Reporting procedures ...................................................................................................... 132 Location Reporting Control procedure ...................................................................................... 133 Location Report procedure ....................................................................................................... 133 Location Report Failure Indication procedure ........................................................................... 133 Overload procedure ....................................................................................................................... 134 Overload Start procedure......................................................................................................... 134 Overload Stop procedure .......................................................................................................... 134 Write-Replace Warning procedure ................................................................................................. 134 eNB Direct Information Transfer procedure ................................................................................... 135 MME Direct Information Transfer procedure ................................................................................. 135 S1 CDMA2000 Tunnelling procedures .......................................................................................... 136 Downlink S1 CDMA2000 Tunnelling procedure ...................................................................... 136 Uplink S1 CDMA2000 Tunnelling procedure ........................................................................... 136 Kill procedure ............................................................................................................................... 137 LPPa Transport procedures ............................................................................................................ 137 Downlink UE Associated LPPa Transport procedure ................................................................ 138 Uplink UE Associated LPPa Transport procedure ..................................................................... 138 Downlink Non UE Associated LPPa Transport procedure ......................................................... 138 Uplink Non UE Associated LPPa Transport procedure ............................................................. 139 Trace procedures ........................................................................................................................... 139 Trace Start procedure ............................................................................................................... 139

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19.2.2.19.2 19.2.2.19.3 19.2.2.19.4

Trace Failure Indication procedure ........................................................................................... 140 Deactivate Trace procedure ...................................................................................................... 140 Cell Traffic Trace procedure .................................................................................................... 140

20

X2 Interface .................................................................................................................................... 141

20.1 User Plane ............................................................................................................................................... 141 20.2 Control Plane ........................................................................................................................................... 141 20.2.1 X2-CP Functions ................................................................................................................................ 142 20.2.2 X2-CP Procedures .............................................................................................................................. 142 20.2.2.1 Handover Preparation procedure .................................................................................................... 143 20.2.2.2 Handover Cancel procedure ........................................................................................................... 144 20.2.2.3 UE Context Release procedure ...................................................................................................... 145 20.2.2.4 SN Status Transfer procedure ........................................................................................................ 145 20.2.2.5 Error Indication procedure ............................................................................................................. 145 20.2.2.6 Load Indication procedure ............................................................................................................. 146 20.2.2.7 X2 Setup procedure ....................................................................................................................... 146 20.2.2.8 eNB Configuration Update procedure ............................................................................................ 147 20.2.2.9 Reset procedure ............................................................................................................................. 147 20.2.2.10 Resource Status Reporting Initiation procedure .............................................................................. 147 20.2.2.11 Resource Status Reporting procedure ............................................................................................. 148 20.2.2.12 Radio Link Failure Indication procedure ........................................................................................ 148 20.2.2.13 Handover Report procedure ........................................................................................................... 149 20.2.2.14 Mobility Settings Change procedure .............................................................................................. 149 20.2.2.15 Cell Activation procedure .............................................................................................................. 150 20.2.3 Void ................................................................................................................................................... 150

21
21.1 21.2 21.3

System and Terminal complexity .................................................................................................... 150
Overall System complexity....................................................................................................................... 150 Physical layer complexity......................................................................................................................... 150 UE complexity ......................................................................................................................................... 150

22

Support for self-configuration and self-optimisation ........................................................................ 150
Definitions ............................................................................................................................................... 150 UE Support for self-configuration and self-optimisation............................................................................ 152 Self-configuration .................................................................................................................................... 152 Dynamic configuration of the S1-MME interface ................................................................................ 152 Prerequisites.................................................................................................................................. 152 SCTP initialization ........................................................................................................................ 152 Application layer initialization ....................................................................................................... 153 Dynamic Configuration of the X2 interface ......................................................................................... 153 Prerequisites.................................................................................................................................. 153 SCTP initialization ........................................................................................................................ 153 Application layer initialization ....................................................................................................... 153 Automatic Neighbour Relation Function ............................................................................................. 153 Intra-LTE/frequency Automatic Neighbour Relation Function ............................................................. 155 Inter-RAT/Inter-frequency Automatic Neighbour Relation Function..................................................... 156 Framework for PCI Selection .............................................................................................................. 157 TNL address discovery ....................................................................................................................... 157 TNL address discovery of candidate eNB via S1 interface .............................................................. 157 Self-optimisation ...................................................................................................................................... 157 Support for Mobility Load Balancing .................................................................................................. 157 General ......................................................................................................................................... 157 Load reporting............................................................................................................................... 158 Load balancing action based on handovers ..................................................................................... 159 Adapting handover and/or reselection configuration ....................................................................... 159 Support for Mobility Robustness Optimisation .................................................................................... 159 Support for RACH Optimisation ......................................................................................................... 160 Support for Energy Saving .................................................................................................................. 161 General ......................................................................................................................................... 161 Solution description....................................................................................................................... 161 O&M requirements........................................................................................................................ 161 Void ........................................................................................................................................................ 162 Void ........................................................................................................................................................ 162

22.1 22.2 22.3 22.3.1 22.3.1.1 22.3.1.2 22.3.1.3 22.3.2 22.3.2.1 22.3.2.2 22.3.2.3 22.3.2a 22.3.3 22.3.4 22.3.5 22.3.6 22.3.6.1 22.4 22.4.1 22.4.1.1 22.4.1.2 22.4.1.3 22.4.1.4 22.4.2 22.4.3 22.4.4 22.4.4.1 22.4.4.2 22.4.4.3 22.5 22.6

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23.1 23.1.1 23.2 23.2.1 23.2.2 23.3 23.3.1 23.3.2

Others ............................................................................................................................................. 162
Support for real time IMS services............................................................................................................ 162 IMS Emergency Call .......................................................................................................................... 162 Subscriber and equipment trace ................................................................................................................ 162 Signalling activation ........................................................................................................................... 162 Management activation ....................................................................................................................... 163 E-UTRAN Support for Warning Systems ................................................................................................. 163 Earthquake and Tsunami Warning System .......................................................................................... 163 Commercial Mobile Alert System ............................................................................................................. 163

Annex A (informative): A.1 A.2

NAS Overview .......................................................................................... 164

Services and Functions .................................................................................................................... 164 NAS protocol states & state transitions............................................................................................ 164 MAC and RRC Control ........................................................................... 165

Annex B (informative): B.1 B.2

Difference between MAC and RRC control..................................................................................... 165 Void ............................................................................................................................................... 165 Void .......................................................................................................... 166 Void .......................................................................................................... 166 Void .......................................................................................................... 166 Void .......................................................................................................... 166 Guideline for E-UTRAN UE capabilities ................................................ 167 Void .......................................................................................................... 168 SPID ranges ad mapping of SPID values to cell reselection and interRAT/inter frequency handover priorities ............................................... 168

Annex C (informative): Annex D (informative): Annex E (informative): Annex F (informative): Annex G (informative): Annex H (informative): Annex I (informative):
I.1 I.2

SPID ranges ............................................................................................................................................. 168 Reference SPID values ............................................................................................................................. 168

Annex J (informative):

Change history ......................................................................................... 170

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Foreword
This Technical Specification has been produced by the 3rd Generation Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document.

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1

Scope

The present document provides an overview and overall description of the E-UTRAN radio interface protocol architecture. Details of the radio interface protocols are specified in companion specifications of the 36 series.

2

References
References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. [1] [2] [3] [4] [5] [6] [7] [8] [9] [11] [12] [13] [14] [15] [16] [17] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications" 3GPP TR 25.913: "Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN)" 3GPP TS 36.201: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer; General description". 3GPP TS 36.211:"Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation " 3GPP TS 36.212: "Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding" 3GPP TS 36.213: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures" 3GPP TS 36.214: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer; Measurements" IETF RFC 4960 (09/2007): "Stream Control Transmission Protocol" 3GPP TS 36.302: "Evolved Universal Terrestrial Radio Access (E-UTRA); Services provided by the physical layer" 3GPP TS 36.304: "Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) procedures in idle mode" 3GPP TS 36.306: "Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio access capabilities" 3GPP TS 36.321: "Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Acces Control (MAC) protocol specification" 3GPP TS 36.322: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Link Control (RLC) protocol specification" 3GPP TS 36.323: "Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification" 3GPP TS 36.331: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC) protocol specification". 3GPP TS 23.401: "Technical Specification Group Services and System Aspects; GPRS enhancements for EUTRAN access".

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

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[18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38]

3GPP TR 24.801: "3GPP System Architecture Evolution (SAE); CT WG1 aspects". 3GPP TS 23.402: "3GPP System Architecture Evolution: Architecture Enhancements for non-3GPP accesses". 3GPP TR 24.301: "Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3". 3GPP TS 36.133: "Evolved Universal Terrestrial Radio Access (E-UTRA); "Requirements for support of radio resource management". 3GPP TS 33.401: "3GPP System Architecture Evolution: Security Architecture". 3GPP TS 23.272: "Circuit Switched Fallback in Evolved Packet System; Stage 2". 3GPP TS 33.401: "3GPP System Architecture Evolution: Security Architecture". 3GPP TS 36.413: "Evolved Universal Terrestrial Radio Access Network (E-UTRAN); S1 Application Protocol (S1AP)". 3GPP TS 23.003: "Numbering, addressing and identification". 3GPP TR 25.922: "Radio Resource Management Strategies". 3GPP TS 23.216: "Single Radio voice Call continuity (SRVCC); Stage 2". 3GPP TS 32.421: "Subscriber and equipment trace: Trace concepts and requirements". 3GPP TS 32.422: "Subscriber and equipment trace; Trace control and configuration management". 3GPP TS 32.423: "Subscriber and equipment trace: Trace data definition and management". 3GPP TS 25.346: "Universal Mobile Telecommunications System (UMTS); Introduction of the Multimedia Broadcast/Multicast Service (MBMS) in the Radio Access Network (RAN); Stage 2". 3GPP TS 22.220: "Service Requirements for Home NodeBs and Home eNodeBs". 3GPP TS 22.268: "Public Warning System (PWS) Requirements". IETF RFC 3168 (09/2001): "The Addition of Explicit Congestion Notification (ECN) to IP". 3GPP TS 25.446: "MBMS synchronisation protocol (SYNC)". 3GPP TS 22.168: "Earthquake and Tsunami Warning System (ETWS) requirements; Stage 1". 3GPP TR 25.306: " UE Radio Access capabilities".

3
3.1

Definitions, symbols and abbreviations
Definitions

For the purposes of the present document, the following terms and definitions apply. Carrier frequency: center frequency of the cell. E-RAB: An E-RAB uniquely identifies the concatenation of an S1 Bearer and the corresponding Data Radio Bearer. When an E-RAB exists, there is a one-to-one mapping between this E-RAB and an EPS bearer of the Non Access Stratum as defined in [17]. CSG Cell: A cell broadcasting a CSG indicator set to true and a specific CSG identity. Hybrid cell: A cell broadcasting a CSG indicator set to false and a specific CSG identity. This cell is accessible as a CSG cell by UEs which are members of the CSG and as a normal cell by all other UEs. MBMS-dedicated cell: cell dedicated to MBMS transmission. MBMS-dedicated cell is not supported in this release.

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Frequency layer: set of cells with the same carrier frequency. Handover: procedure that changes the serving cell of a UE in RRC_CONNECTED. MBMS/Unicast-mixed: cell supporting both unicast and MBMS transmissions. Membership Verification: The process that checks whether a UE is a member or non-member of a hybrid cell Access Control: The process that checks whether a UE is allowed to access and to be granted services in a closed cell CSG ID Validation: The process that checks whether the CSG ID received via handover messages is the same as the one broadcast by the target E-UTRAN

3.2

Abbreviations

For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 [1]. 1xCSFB ACK ACLR AM AMBR ANR ARQ AS BCCH BCH BSR C/I CAZAC CBC CMAS CMC CP C-plane C-RNTI CQI CRC CSA CSG DCCH DL DFTS DRB DRX DTCH DTX DwPTS ECGI ECM EMM E-CID eNB EPC EPS E-RAB ETWS E-UTRA E-UTRAN FDD Circuit Switched Fallback to 1xRTT Acknowledgement Adjacent Channel Leakage Ratio Acknowledged Mode Aggregate Maximum Bit Rate Automatic Neighbour Relation Automatic Repeat Request Access Stratum Broadcast Control Channel Broadcast Channel Buffer Status Report Carrier-to-Interference Power Ratio Constant Amplitude Zero Auto-Correlation Cell Broadcast Center Commercial Mobile Alert Service Connection Mobility Control Cyclic Prefix Control Plane Cell RNTI Channel Quality Indicator Cyclic Redundancy Check Common Subframe Allocation Closed Subscriber Group Dedicated Control Channel Downlink DFT Spread OFDM Data Radio Bearer Discontinuous Reception Dedicated Traffic Channel Discontinuous Transmission Downlink Pilot Time Slot E-UTRAN Cell Global Identifier EPS Connection Management EPS Mobility Management Enhanced Cell-ID (positioning method) E-UTRAN NodeB Evolved Packet Core Evolved Packet System E-UTRAN Radio Access Bearer Earthquake and Tsunami Warning System Evolved UTRA Evolved UTRAN Frequency Division Duplex

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FDM GERAN GNSS GSM GBR GP HARQ HO HRPD HSDPA ICIC IP LB LCG LCR LPPa LTE MAC MBMS MBR MBSFN MCCH MCE MCH MCS MIB MIMO MME MSA MSI MSP MTCH NACK NAS NCC NH NNSF NR NRT OFDM OFDMA OTDOA P-GW P-RNTI PA PAPR PBCH PBR PCCH PCFICH PCH PCI PDCCH PDSCH PDCP PDU PHICH PHY PLMN PMCH PRACH PRB

Frequency Division Multiplexing GSM EDGE Radio Access Network Global Navigation Satellite System Global System for Mobile communication Guaranteed Bit Rate Guard Period Hybrid ARQ Handover High Rate Packet Data High Speed Downlink Packet Access Inter-Cell Interference Coordination Internet Protocol Load Balancing Logical Channel Group Low Chip Rate LTE Positioning Protocol Annex Long Term Evolution Medium Access Control Multimedia Broadcast Multicast Service Maximum Bit Rate Multimedia Broadcast multicast service Single Frequency Network Multicast Control Channel Multi-cell/multicast Coordination Entity Multicast Channel Modulation and Coding Scheme Master Information Block Multiple Input Multiple Output Mobility Management Entity MCH Subframe Allocation MCH Scheduling Information MCH Scheduling Period Multicast Traffic Channel Negative Acknowledgement Non-Access Stratum Next Hop Chaining Counter Next Hop key NAS Node Selection Function Neighbour cell Relation Neighbour Relation Table Orthogonal Frequency Division Multiplexing Orthogonal Frequency Division Multiple Access Observed Time Difference Of Arrival (positioning method) PDN Gateway Paging RNTI Power Amplifier Peak-to-Average Power Ratio Physical Broadcast CHannel Prioritised Bit Rate Paging Control Channel Physical Control Format Indicator CHannel Paging Channel Physical Cell Identifier Physical Downlink Control CHannel Physical Downlink Shared CHannel Packet Data Convergence Protocol Protocol Data Unit Physical Hybrid ARQ Indicator CHannel Physical layer Public Land Mobile Network Physical Multicast CHannel Physical Random Access CHannel Physical Resource Block

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PSC PUCCH PUSCH PWS QAM QCI QoS RA-RNTI RAC RACH RAT RB RBC RF RIM RLC RNC RNL RNTI ROHC RRC RRM RU S-GW S1-MME SI SIB SI-RNTI S1-U SAE SAP SC-FDMA SCH SDF SDMA SDU SeGW SFN SPID SR SRB SU TA TB TCP TDD TFT TM TNL TTI UE UL UM UMTS U-plane UTRA UTRAN UpPTS VRB X2-C X2-U

Packet Scheduling Physical Uplink Control CHannel Physical Uplink Shared CHannel Public Warning System Quadrature Amplitude Modulation QoS Class Identifier Quality of Service Random Access RNTI Radio Admission Control Random Access Channel Radio Access Technology Radio Bearer Radio Bearer Control Radio Frequency RAN Information Management Radio Link Control Radio Network Controller Radio Network Layer Radio Network Temporary Identifier Robust Header Compression Radio Resource Control Radio Resource Management Resource Unit Serving Gateway S1 for the control plane System Information System Information Block System Information RNTI S1 for the user plane System Architecture Evolution Service Access Point Single Carrier – Frequency Division Multiple Access Synchronization Channel Service Data Flow Spatial Division Multiple Access Service Data Unit Security Gateway System Frame Number Subscriber Profile ID for RAT/Frequency Priority Scheduling Request Signalling Radio Bearer Scheduling Unit Tracking Area Transport Block Transmission Control Protocol Time Division Duplex Traffic Flow Template Transparent Mode Transport Network Layer Transmission Time Interval User Equipment Uplink Unacknowledged Mode Universal Mobile Telecommunication System User plane Universal Terrestrial Radio Access Universal Terrestrial Radio Access Network Uplink Pilot Time Slot Virtual Resource Block X2-Control plane X2-User plane

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4

Overall architecture

The E-UTRAN consists of eNBs, providing the E-UTRA user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE. The eNBs are interconnected with each other by means of the X2 interface. The eNBs are also connected by means of the S1 interface to the EPC (Evolved Packet Core), more specifically to the MME (Mobility Management Entity) by means of the S1-MME and to the Serving Gateway (S-GW) by means of the S1-U. The S1 interface supports a many-to-many relation between MMEs / Serving Gateways and eNBs. The E-UTRAN architecture is illustrated in Figure 4 below.

MME / S-GW

MME / S-GW

X2

E-UTRAN eNB
X2

eNB
X2

eNB

Figure 4-1: Overall Architecture

4.1
-

Functional Split
Functions for Radio Resource Management: Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Dynamic allocation of resources to UEs in both uplink and downlink (scheduling); IP header compression and encryption of user data stream; Selection of an MME at UE attachment when no routing to an MME can be determined from the information provided by the UE; Routing of User Plane data towards Serving Gateway; Scheduling and transmission of paging messages (originated from the MME); Scheduling and transmission of broadcast information (originated from the MME or O&M); Measurement and measurement reporting configuration for mobility and scheduling; Scheduling and transmission of PWS (which includes ETWS and CMAS) messages (originated from the MME); CSG handling.

The eNB hosts the following functions:

The MME hosts the following functions (see 3GPP TS 23.401 [17]): NAS signalling; NAS signalling security;

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AS Security control; Inter CN node signalling for mobility between 3GPP access networks; Idle mode UE Reachability (including control and execution of paging retransmission); Tracking Area list management (for UE in idle and active mode); PDN GW and Serving GW selection; MME selection for handovers with MME change; SGSN selection for handovers to 2G or 3G 3GPP access networks; Roaming; Authentication; Bearer management functions including dedicated bearer establishment; Support for PWS (which includes ETWS and CMAS) message transmission; Optionally performing paging optimisation.

NOTE 1: For macro eNBs, the MME should not filter the PAGING message based on the CSG IDs. The Serving Gateway (S-GW) hosts the following functions (see 3GPP TS 23.401 [17]): The local Mobility Anchor point for inter-eNB handover; Mobility anchoring for inter-3GPP mobility; E-UTRAN idle mode downlink packet buffering and initiation of network triggered service request procedure; Lawful Interception; Packet routeing and forwarding; Transport level packet marking in the uplink and the downlink; Accounting on user and QCI granularity for inter-operator charging; UL and DL charging per UE, PDN, and QCI.

The PDN Gateway (P-GW) hosts the following functions (see 3GPP TS 23.401 [17]): Per-user based packet filtering (by e.g. deep packet inspection); Lawful Interception; UE IP address allocation; Transport level packet marking in the downlink; UL and DL service level charging, gating and rate enforcement; DL rate enforcement based on APN-AMBR;

This is summarized on the figure below where yellow boxes depict the logical nodes, white boxes depict the functional entities of the control plane and blue boxes depict the radio protocol layers. NOTE 2: it is assumed that no other logical E-UTRAN node than the eNB is needed for RRM purposes. Moreover, due to the different usage of inter-cell RRM functionalities, each inter-cell RRM functionality should be considered separately in order to assess whether it should be handled in a centralised manner or in a distributed manner. NOTE 3: MBMS related functions in E-UTRAN are described separately in subclause 15.

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Figure 4.1-1: Functional Split between E-UTRAN and EPC

4.2
4.2.1 4.2.2

Interfaces
S1 Interface X2 Interface

4.3
4.3.1

Radio Protocol architecture
User plane

In this subclause, the radio protocol architecture of E-UTRAN is given for the user plane and the control plane.

The figure below shows the protocol stack for the user-plane, where PDCP, RLC and MAC sublayers (terminated in eNB on the network side) perform the functions listed for the user plane in subclause 6, e.g. header compression, ciphering, scheduling, ARQ and HARQ;

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UE PDCP RLC MAC PHY

eNB PDCP RLC MAC PHY

Figure 4.3.1-1: User-plane protocol stack

4.3.2
-

Control plane

The figure below shows the protocol stack for the control-plane, where: PDCP sublayer (terminated in eNB on the network side) performs the functions listed for the control plane in subclause 6, e.g. ciphering and integrity protection; RLC and MAC sublayers (terminated in eNB on the network side) perform the same functions as for the user plane; RRC (terminated in eNB on the network side) performs the functions listed in subclause 7, e.g.: Broadcast; Paging; RRC connection management; RB control; Mobility functions; UE measurement reporting and control.

NAS control protocol (terminated in MME on the network side) performs among other things: EPS bearer management; Authentication; ECM-IDLE mobility handling; Paging origination in ECM-IDLE; Security control. the NAS control protocol is not covered by the scope of this TS and is only mentioned for information.

NOTE:

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Figure 4.3.2-1: Control-plane protocol stack

4.4

Synchronization

Diverse methods and techniques are preferred depending on synchronization requirements. As no single method can cover all E-UTRAN applications a logical port at eNB may be used for reception of timing and/or frequency and/or phase inputs pending to the synchronization method chosen.

4.5 IP fragmentation
Fragmentation function in IP layer on S1 and X2 shall be supported. Configuration of S1-U (X2-U) link MTU in the eNB according to the MTU of the network domain the node belongs to shall be considered as a choice at network deployment. The network may employ various methods to handle IP fragmentation, but the specific methods to use are implementation dependant.

4.6
4.6.1

Support of HeNBs
Architecture

Figure 4.6.1-1 shows a logical architecture for the HeNB that has a set of S1 interfaces to connect the HeNB to the EPC. The configuration and authentication entities as shown here should be common to HeNBs and HNBs.

Figure 4.6.1-1: E-UTRAN HeNB Logical Architecture The E-UTRAN architecture may deploy a Home eNB Gateway (HeNB GW) to allow the S1 interface between the HeNB and the EPC to scale to support a large number of HeNBs. The HeNB GW serves as a concentrator for the C-

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Plane, specifically the S1-MME interface. The S1-U interface from the HeNB may be terminated at the HeNB GW, or a direct logical U-Plane connection between HeNB and S-GW may be used (as shown in Figure 4.6.1-1). This version of the specification does not support X2 connectivity of HeNBs. The S1 interface is defined as the interface: Between the HeNB GW and the Core Network, Between the HeNB and the HeNB GW, Between the HeNB and the Core Network, Between the eNB and the Core Network.

The HeNB GW appears to the MME as an eNB. The HeNB GW appears to the HeNB as an MME. The S1 interface between the HeNB and the EPC is the same whether the HeNB is connected to the EPC via a HeNB GW or not. The HeNB GW shall connect to the EPC in a way that inbound and outbound mobility to cells served by the HeNB GW shall not necessarily require inter MME handovers. One HeNB serves only one cell. The functions supported by the HeNB shall be the same as those supported by an eNB (with the possible exception of NNSF) and the procedures run between a HeNB and the EPC shall be the same as those between an eNB and the EPC.

S1

S1

Figure 4.6.1-2: Overall E-UTRAN Architecture with deployed HeNB GW.

4.6.2

Functional Split

The HeNB hosts the same functions as an eNB as described in section 4.1, with the following additional specifications in case of connection to the HeNB GW: Discovery of a suitable Serving HeNB GW A HeNB shall only connect to a single HeNB GW at one time, namely no S1 Flex function shall be used at the HeNB. The HeNB will not simultaneously connect to another HeNB GW, or another MME.

The TAC and PLMN ID used by the HeNB shall also be supported by the HeNB GW.

X2

S1

S1

S1

S1

S1

X2

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Selection of an MME at UE attachment is hosted by the HeNB GW instead of the HeNB; HeNBs may be deployed without network planning. A HeNB may be moved from one geographical area to another and therefore it may need to connect to different HeNB GWs depending on its location.

The HeNB GW hosts the following functions: Relaying UE-associated S1 application part messages between the MME serving the UE and the HeNB serving the UE; Terminating non-UE associated S1 application part procedures towards the HeNB and towards the MME. Note that when a HeNB GW is deployed, non-UE associated procedures shall be run between HeNBs and the HeNB GW and between the HeNB GW and the MME. Optionally terminating S1-U interface with the HeNB and with the S-GW. Supporting TAC and PLMN ID used by the HeNB. X2 interfaces shall not be established between the HeNB GW and other nodes.

-

A list of CSG IDs may be included in the PAGING message. If included, the HeNB GW may use the list of CSG IDs for paging optimization. In addition to functions specified in section 4.1, the MME hosts the following functions: Access control for UEs that are members of Closed Subscriber Groups (CSG): In case of handovers to CSG cells, access control is based on the target CSG ID provided to the MME by the serving E-UTRAN.

Membership Verification for UEs handing over to hybrid cells: In case of handovers to hybrid cells Membership Verification is triggered by the presence of the Cell Access Mode and it is based on the target CSG ID provided to the MME by the serving E-UTRAN.

-

CSG membership status signalling to the target E-UTRAN in case of attachment/handover to hybrid cells and in case of the change of membership status when a UE is served by a CSG cell or a hybrid cell. Supervising the eNB action after the change in the membership status of a UE. Routing of handover messages towards HeNB GWs based on the TAI contained in the handover message. The MME or HeNB GW should not include the list of CSG IDs for paging when sending the paging message directly to an untrusted HeNB or eNB.

NOTE:

4.6.3
4.6.3.1

Interfaces
Protocol Stack for S1 User Plane

The S1-U data plane is defined between the HeNB, HeNB GW and the S-GW. The figures below shows the S1-U protocol stack with and without the HeNB GW.

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Figure 4.6.3.1-1: User plane for S1-U interface for HeNB without HeNB GW

Figure 4.6.3.1-2: User plane for S1-U interface for HeNB with HeNB GW The HeNB GW may optionally terminate the user plane towards the HeNB and towards the S-GW, and provide a relay function for relaying User Plane data between the HeNB and the S-GW.

4.6.3.2

Protocol Stacks for S1 Control Plane

The two figures below show the S1-MME protocol stacks with and without the HeNB GW. When the HeNB GW is not present (Fig. 4.6.3.2-1), all the S1 procedures are terminated at the HeNB and the MME. When present (Fig. 4.6.3.2-2), the HeNB GW shall terminate the non-UE-dedicated procedures – both with the HeNB, and with the MME. The HeNB GW shall provide a relay function for relaying Control Plane data between the HeNB and the MME. The scope of any protocol function associated to a non-UE-dedicated procedure shall be between HeNB and HeNB GW and/or between HeNB GW and MME. Any protocol function associated to an UE-dedicated-procedure shall reside within the HeNB and the MME only.

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Figure 4.6.3.2-1: Control plane for S1-MME Interface for HeNB to MME without the HeNB GW

Figure 4.6.3.2-2: Control plane for S1-MME Interface for HeNB to MME with the HeNB GW

4.6.4 Void

5
-

Physical Layer for E-UTRA
Type 1, applicable to FDD, Type 2, applicable to TDD.

Downlink and uplink transmissions are organized into radio frames with 10 ms duration. Two radio frame structures are supported:

Frame structure Type 1 is illustrated in Figure 5.1-1. Each 10 ms radio frame is divided into ten equally sized subframes. Each sub-frame consists of two equally sized slots. For FDD, 10 subframes are available for downlink transmission and 10 subframes are available for uplink transmissions in each 10 ms interval. Uplink and downlink transmissions are separated in the frequency domain.

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Figure 5.1-1: Frame structure type 1 Frame structure Type 2 is illustrated in Figure 5.1-2. Each 10 ms radio frame consists of two half-frames of 5 ms each. Each half-frame consists of eight slots of length 0.5 ms and three special fields: DwPTS, GP and UpPTS. The length of DwPTS and UpPTS is configurable subject to the total length of DwPTS, GP and UpPTS being equal to 1ms. Both 5ms and 10ms switch-point periodicity are supported. Subframe 1 in all configurations and subframe 6 in configuration with 5ms switch-point periodicity consist of DwPTS, GP and UpPTS. Subframe 6 in configuration with 10ms switch-point periodicity consists of DwPTS only. All other subframes consist of two equally sized slots. For TDD, GP is reserved for downlink to uplink transition. Other Subframes/Fields are assigned for either downlink or uplink transmission. Uplink and downlink transmissions are separated in the time domain.

Figure 5.1-2: Frame structure type 2 (for 5ms switch-point periodicity) Table 5.1-1: Uplink-downlink allocations.
Configuration 0 1 2 3 4 5 6 Switch-point periodicity 5 ms 5 ms 5 ms 10 ms 10 ms 10 ms 5 ms 0 D D D D D D D 1 S S S S S S S 2 U U U U U U U Subframe number 3 4 5 6 7 U U D S U U D D S U D D D S U U U D D D U D D D D D D D D D U U D S U 8 U U D D D D U 9 U D D D D D D

The physical channels of E-UTRA are: Physical broadcast channel (PBCH) The coded BCH transport block is mapped to four subframes within a 40 ms interval; 40 ms timing is blindly detected, i.e. there is no explicit signalling indicating 40 ms timing; Each subframe is assumed to be self-decodable, i.e. the BCH can be decoded from a single reception, assuming sufficiently good channel conditions.

Physical control format indicator channel (PCFICH) Informs the UE about the number of OFDM symbols used for the PDCCHs;

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Transmitted in every downlink or special subframe.

Physical downlink control channel (PDCCH) Informs the UE about the resource allocation of PCH and DL-SCH, and Hybrid ARQ information related to DL-SCH; Carries the uplink scheduling grant.

Physical Hybrid ARQ Indicator Channel (PHICH) Carries Hybrid ARQ ACK/NAKs in response to uplink transmissions.

Physical downlink shared channel (PDSCH) Carries the DL-SCH and PCH.

Physical multicast channel (PMCH) Carries the MCH.

Physical uplink control channel (PUCCH) Carries Hybrid ARQ ACK/NAKs in response to downlink transmission; Carries Scheduling Request (SR); Carries CQI reports.

Physical uplink shared channel (PUSCH) Carries the UL-SCH.

Physical random access channel (PRACH) Carries the random access preamble.

5.1
5.1.1

Downlink Transmission Scheme
Basic transmission scheme based on OFDM

The downlink transmission scheme is based on conventional OFDM using a cyclic prefix. The OFDM sub-carrier spacing is f = 15 kHz. 12 consecutive sub-carriers during one slot correspond to one downlink resource block. In the frequency domain, the number of resource blocks, NRB, can range from NRB-min = 6 to NRB-max = 110. In addition there is also a reduced sub-carrier spacing flow = 7.5 kHz, only for MBMS-dedicated cell. In the case of 15 kHz sub-carrier spacing there are two cyclic-prefix lengths, corresponding to seven and six OFDM symbols per slot respectively. Normal cyclic prefix: TCP = 160 Ts (OFDM symbol #0) , TCP = 144 Ts (OFDM symbol #1 to #6) Extended cyclic prefix: TCP-e = 512 Ts (OFDM symbol #0 to OFDM symbol #5) where Ts = 1/ (2048 f)

In case of 7.5 kHz sub-carrier spacing, there is only a single cyclic prefix length TCP-low = 1024 Ts, corresponding to 3 OFDM symbols per slot. In case of FDD, operation with half duplex from UE point of view is supported.

5.1.2

Physical-layer processing

The downlink physical-layer processing of transport channels consists of the following steps:

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CRC insertion: 24 bit CRC is the baseline for PDSCH; Channel coding: Turbo coding based on QPP inner interleaving with trellis termination; Physical-layer hybrid-ARQ processing; Channel interleaving; Scrambling: transport-channel specific scrambling on DL-SCH, BCH, and PCH. Common MCH scrambling for all cells involved in a specific MBSFN transmission; Modulation: QPSK, 16QAM, and 64QAM; Layer mapping and pre-coding; Mapping to assigned resources and antenna ports.

5.1.3
-

Physical downlink control channel
4 and consists of:

The downlink control signalling (PDCCH) is located in the first n OFDM symbols where n

Transport format and resource allocation related to DL-SCH and PCH, and hybrid ARQ information related to DL-SCH; Transport format, resource allocation, and hybrid-ARQ information related to UL-SCH;

Transmission of control signalling from these groups is mutually independent. Multiple physical downlink control channels are supported and a UE monitors a set of control channels. Control channels are formed by aggregation of control channel elements, each control channel element consisting of a set of resource elements. Different code rates for the control channels are realized by aggregating different numbers of control channel elements. QPSK modulation is used for all control channels. Each separate control channel has its own set of x-RNTI. There is an implicit relation between the uplink resources used for dynamically scheduled data transmission, or the DL control channel used for assignment, and the downlink ACK/NAK resource used for feedback

5.1.4

Downlink Reference signal

The downlink reference signals consist of known reference symbols inserted in the first and third last OFDM symbol of each slot. There is one reference signal transmitted per downlink antenna port. The number of downlink antenna ports equals 1, 2, or 4. The two-dimensional reference signal sequence is generated as the symbol-by-symbol product of a two-dimensional orthogonal sequence and a two-dimensional pseudo-random sequence. There are 3 different twodimensional orthogonal sequences and 170 different two-dimensional pseudo-random sequences. Each cell identity corresponds to a unique combination of one orthogonal sequence and one pseudo-random sequence, thus allowing for 504 unique cell identities 168 cell identity groups with 3 cell identities in each group). Frequency hopping can be applied to the downlink reference signals. The frequency hopping pattern has a period of one frame (10 ms). Each frequency hopping pattern corresponds to one cell identity group. The downlink MBSFN reference signals consist of known reference symbols inserted every other sub-carrier in the 3rd, 7th and 11th OFDM symbol of sub-frame in case of 15kHz sub-carrier spacing and extended cyclic prefix

5.1.5

Downlink multi-antenna transmission

Multi-antenna transmission with 2 and 4 transmit antennas is supported. The maximum number of codeword is two irrespective to the number of antennas with fixed mapping between code words to layers. Spatial division multiplexing (SDM) of multiple modulation symbol streams to a single UE using the same timefrequency (-code) resource, also referred to as Single-User MIMO (SU-MIMO) is supported. When a MIMO channel is

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solely assigned to a single UE, it is known as SU-MIMO. Spatial division multiplexing of modulation symbol streams to different UEs using the same time-frequency resource, also referred to as MU-MIMO, is also supported. There is semi-static switching between SU-MIMO and MU-MIMO per UE. In addition, the following techniques are supported: Code-book-based pre-coding with a single pre-coding feedback per full system bandwidth when the system bandwidth (or subset of resource blocks) is smaller or equal to12RB and per 5 adjacent resource blocks or the full system bandwidth (or subset of resource blocks) when the system bandwidth is larger than 12RB. Rank adaptation with single rank feedback referring to full system bandwidth. Node B can override rank report.

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5.1.6

MBSFN transmission

MBSFN is supported for the MCH transport channel. Multiplexing of transport channels using MBSFN and nonMBSFN transmission is done on a per-sub-frame basis. Additional reference symbols, transmitted using MBSFN are transmitted within MBSFN subframes.

5.1.7
5.1.7.1

Physical layer procedure
Link adaptation

Link adaptation (AMC: adaptive modulation and coding) with various modulation schemes and channel coding rates is applied to the shared data channel. The same coding and modulation is applied to all groups of resource blocks belonging to the same L2 PDU scheduled to one user within one TTI and within a single stream.

5.1.7.2

Power Control

Downlink power control can be used.

5.1.7.3

Cell search

Cell search is the procedure by which a UE acquires time and frequency synchronization with a cell and detects the Cell ID of that cell. E-UTRA cell search supports a scalable overall transmission bandwidth corresponding to 72 sub-carriers and upwards. E-UTRA cell search is based on following signals transmitted in the downlink: the primary and secondary synchronization signals, the downlink reference signals. The primary and secondary synchronization signals are transmitted over the centre 72 sub-carriers in the first and sixth subframe of each frame. Neighbour-cell search is based on the same downlink signals as initial cell search.

5.1.8
-

Physical layer measurements definition

The physical layer measurements to support mobility are classified as: within E-UTRAN (intra-frequency, inter-frequency); between E-UTRAN and GERAN/UTRAN (inter-RAT); between E-UTRAN and non-3GPP RAT (Inter 3GPP access system mobility).

For measurements within E-UTRAN at least two basic UE measurement quantities shall be supported: Reference symbol received power (RSRP); E-UTRA carrier received signal strength indicator (RSSI).

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5.2
5.2.1

Uplink Transmission Scheme
Basic transmission scheme

For both FDD and TDD, the uplink transmission scheme is based on single-carrier FDMA, more specifically DFTSOFDM.

Figure 5.2.1-1: Transmitter scheme of SC-FDMA The uplink sub-carrier spacing f = 15 kHz. The sub-carriers are grouped into sets of 12 consecutive sub-carriers, corresponding to the uplink resource blocks. 12 consecutive sub-carriers during one slot correspond to one uplink resource block. In the frequency domain, the number of resource blocks, NRB, can range from NRB-min = 6 to NRB-max = 110. There are two cyclic-prefix lengths defined: Normal cyclic prefix and extended cyclic prefix corresponding to seven and six SC-FDMA symbol per slot respectively. Normal cyclic prefix: TCP = 160 Ts (SC-FDMA symbol #0) , TCP = 144 Ts (SC-FDMA symbol #1 to #6) Extended cyclic prefix: TCP-e = 512 Ts (SC-FDMA symbol #0 to SC-FDMA symbol #5)

5.2.2
-

Physical-layer processing

The uplink physical layer processing of transport channels consists of the following steps: CRC insertion: 24 bit CRC is the baseline for PUSCH; Channel coding: turbo coding based on QPP inner interleaving with trellis termination; Physical-layer hybrid-ARQ processing; Scrambling: UE-specific scrambling; Modulation: QPSK, 16QAM, and 64QAM (64 QAM optional in UE); Mapping to assigned resources and antennas ports.

5.2.3

Physical uplink control channel

The PUCCH shall be mapped to a control channel resource in the uplink. A control channel resource is defined by a code and two resource blocks, consecutive in time, with hopping at the slot boundary. Depending on presence or absence of uplink timing synchronization, the uplink physical control signalling can differ. In the case of time synchronization being present, the outband control signalling consists of: CQI; ACK/NAK; Scheduling Request (SR).

The CQI informs the scheduler about the current channel conditions as seen by the UE. If MIMO transmission is used, the CQI includes necessary MIMO-related feedback. The HARQ feedback in response to downlink data transmission consists of a single ACK/NAK bit per HARQ process.

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PUCCH resources for SR and CQI reporting are assigned and can be revoked through RRC signalling. An SR is not necessarily assigned to UEs acquiring synchronization through the RACH (i.e. synchronised UEs may or may not have a dedicated SR channel). PUCCH resources for SR and CQI are lost when the UE is no longer synchronized.

5.2.4

Uplink Reference signal

Uplink reference signals [for channel estimation for coherent demodulation] are transmitted in the 4-th block of the slot [assumed normal CP]. The uplink reference signals sequence length equals the size (number of sub-carriers) of the assigned resource. The uplink reference signals are based on prime-length Zadoff-chu sequences that are cyclically extended to the desired length. Multiple reference signals can be created: Based on different Zadoff-Chu sequence from the same set of Zadoff-Chu sequences; Different shifts of the same sequence.

5.2.5

Random access preamble

The physical layer random access burst consists of a cyclic prefix, a preamble, and a guard time during which nothing is transmitted. The random access preambles are generated from Zadoff-Chu sequences with zero correlation zone, ZC-ZCZ, generated from one or several root Zadoff-Chu sequences.

5.2.6

Uplink multi-antenna transmission

The baseline antenna configuration for uplink MIMO is MU-MIMO. To allow for MU-MIMO reception at the Node B, allocation of the same time and frequency resource to several UEs, each of which transmitting on a single antenna, is supported. Closed loop type adaptive antenna selection transmit diversity shall be supported for FDD (optional in UE).

5.2.7
5.2.7.1

Physical channel procedure
Link adaptation

Uplink link adaptation is used in order to guarantee the required minimum transmission performance of each UE such as the user data rate, packet error rate, and latency, while maximizing the system throughput. Three types of link adaptation are performed according to the channel conditions, the UE capability such as the maximum transmission power and maximum transmission bandwidth etc., and the required QoS such as the data rate, latency, and packet error rate etc. Three link adaptation methods are as follows. Adaptive transmission bandwidth; Transmission power control; Adaptive modulation and channel coding rate.

5.2.7.2

Uplink Power control

Intra-cell power control: the power spectral density of the uplink transmissions can be influenced by the eNB.

5.2.7.3

Uplink timing control

The timing advance is derived from the UL received timing and sent by the eNB to the UE which the UE uses to advance/delay its timings of transmissions to the eNB so as to compensate for propagation delay and thus time align the transmissions from different UEs with the receiver window of the eNB.

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The timing advance command is on a per need basis with a granularity in the step size of 0.52 s (16 Ts).

5.3

Transport Channels

The physical layer offers information transfer services to MAC and higher layers. The physical layer transport services are described by how and with what characteristics data are transferred over the radio interface. An adequate term for this is “Transport Channel”. NOTE: This should be clearly separated from the classification of what is transported, which relates to the concept of logical channels at MAC sublayer.

Downlink transport channel types are: 1. Broadcast Channel (BCH) characterised by: fixed, pre-defined transport format; requirement to be broadcast in the entire coverage area of the cell.

2. Downlink Shared Channel (DL-SCH) characterised by: support for HARQ; support for dynamic link adaptation by varying the modulation, coding and transmit power; possibility to be broadcast in the entire cell; possibility to use beamforming; support for both dynamic and semi-static resource allocation; support for UE discontinuous reception (DRX) to enable UE power saving; the possibility to use slow power control depends on the physical layer.

NOTE:

3. Paging Channel (PCH) characterised by: support for UE discontinuous reception (DRX) to enable UE power saving (DRX cycle is indicated by the network to the UE); requirement to be broadcast in the entire coverage area of the cell; mapped to physical resources which can be used dynamically also for traffic/other control channels.

4. Multicast Channel (MCH) characterised by: requirement to be broadcast in the entire coverage area of the cell; support for MBSFN combining of MBMS transmission on multiple cells; support for semi-static resource allocation e.g. with a time frame of a long cyclic prefix.

Uplink transport channel types are: 1. Uplink Shared Channel (UL-SCH) characterised by: possibility to use beamforming; (likely no impact on specifications) support for dynamic link adaptation by varying the transmit power and potentially modulation and coding; support for HARQ; support for both dynamic and semi-static resource allocation. the possibility to use uplink synchronisation and timing advance depend on the physical layer.

NOTE:

2. Random Access Channel(s) (RACH) characterised by:

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limited control information; collision risk; the possibility to use open loop power control depends on the physical layer solution.

NOTE:

5.3.1

Mapping between transport channels and physical channels

The figures below depict the mapping between transport and physical channels:

Figure 5.3.1-1: Mapping between downlink transport channels and downlink physical channels

Figure 5.3.1-2: Mapping between uplink transport channels and uplink physical channels

5.4
5.4.1

E-UTRA physical layer model
Void

The E-UTRAN physical layer model is captured in TS 36.302 [9].

5.4.2

Void

6

Layer 2

Layer 2 is split into the following sublayers: Medium Access Control (MAC), Radio Link Control (RLC) and Packet Data Convergence Protocol (PDCP). This subclause gives a high level description of the Layer 2 sub-layers in terms of services and functions. The two figures below depict the PDCP/RLC/MAC architecture for downlink and uplink, where:

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Service Access Points (SAP) for peer-to-peer communication are marked with circles at the interface between sublayers. The SAP between the physical layer and the MAC sublayer provides the transport channels. The SAPs between the MAC sublayer and the RLC sublayer provide the logical channels. The multiplexing of several logical channels (i.e. radio bearers) on the same transport channel (i.e. transport block) is performed by the MAC sublayer; In both uplink and downlink, only one transport block is generated per TTI in the non-MIMO case.

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Figure 6-1: Layer 2 Structure for DL

Radio Bearers ROHC PDCP Security Security ROHC

RLC

Segm. ARQ etc

...

Segm. ARQ etc

CCCH Logical Channels

Scheduling / Priority Handling

MAC

Multiplexing

HARQ Transport Channels

Figure 6-2: Layer 2 Structure for UL

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NOTE:

The eNB may not be able to guarantee that a L2 buffer overflow will never occur. If such overflow occurs, UE may discard packets in the L2 buffer.

6.1
6.1.1
-

MAC Sublayer
Services and Functions

This subclause provides an overview on services and functions provided by the MAC sublayer.

The main services and functions of the MAC sublayer include: Mapping between logical channels and transport channels; Multiplexing/demultiplexing of MAC SDUs belonging to one or different logical channels into/from transport blocks (TB) delivered to/from the physical layer on transport channels; scheduling information reporting; Error correction through HARQ; Priority handling between logical channels of one UE; Priority handling between UEs by means of dynamic scheduling; MBMS service identification; Transport format selection; Padding.

6.1.2

Logical Channels

Different kinds of data transfer services as offered by MAC. Each logical channel type is defined by what type of information is transferred. A general classification of logical channels is into two groups: Control Channels (for the transfer of control plane information); Traffic Channels (for the transfer of user plane information).

There is one MAC entity per cell. MAC generally consists of several function blocks (transmission scheduling functions, per UE functions, MBMS functions, MAC control functions, transport block generation…). Transparent Mode is only applied to BCCH and PCCH.

6.1.2.1

Control Channels

Control channels are used for transfer of control plane information only. The control channels offered by MAC are: Broadcast Control Channel (BCCH) A downlink channel for broadcasting system control information. Paging Control Channel (PCCH) A downlink channel that transfers paging information and system information change notifications. This channel is used for paging when the network does not know the location cell of the UE. Common Control Channel (CCCH) Channel for transmitting control information between UEs and network. This channel is used for UEs having no RRC connection with the network.

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Multicast Control Channel (MCCH) A point-to-multipoint downlink channel used for transmitting MBMS control information from the network to the UE, for one or several MTCHs. This channel is only used by UEs that receive MBMS.

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Dedicated Control Channel (DCCH) A point-to-point bi-directional channel that transmits dedicated control information between a UE and the network. Used by UEs having an RRC connection.

6.1.2.2

Traffic Channels

Traffic channels are used for the transfer of user plane information only. The traffic channels offered by MAC are: Dedicated Traffic Channel (DTCH) A Dedicated Traffic Channel (DTCH) is a point-to-point channel, dedicated to one UE, for the transfer of user information. A DTCH can exist in both uplink and downlink. Multicast Traffic Channel (MTCH) A point-to-multipoint downlink channel for transmitting traffic data from the network to the UE. This channel is only used by UEs that receive MBMS.

6.1.3
6.1.3.1

Mapping between logical channels and transport channels
Mapping in Uplink

The figure below depicts the mapping between uplink logical channels and uplink transport channels:
CCCH DCCH DTCH

Uplink Logical channels

RACH

UL-SCH

Uplink Transport channels

Figure 6.1.3.1-1: Mapping between uplink logical channels and uplink transport channels In Uplink, the following connections between logical channels and transport channels exist: CCCH can be mapped to UL-SCH; DCCH can be mapped to UL- SCH; DTCH can be mapped to UL-SCH.

6.1.3.2

Mapping in Downlink

The figure below depicts the mapping between downlink logical channels and downlink transport channels:

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Figure 6.1.3.2-1: Mapping between downlink logical channels and downlink transport channels In Downlink, the following connections between logical channels and transport channels exist: BCCH can be mapped to BCH; BCCH can be mapped to DL-SCH; PCCH can be mapped to PCH; CCCH can be mapped to DL-SCH; DCCH can be mapped to DL-SCH; DTCH can be mapped to DL-SCH; MTCH can be mapped to MCH; MCCH can be mapped to MCH.

6.2

RLC Sublayer

This subclause provides an overview on services, functions and PDU structure provided by the RLC sublayer. Note that: The reliability of RLC is configurable: some radio bearers may tolerate rare losses (e.g. TCP traffic); Radio Bearers are not characterized by a fixed sized data unit (e.g. a fixed sized RLC PDU).

6.2.1
-

Services and Functions

The main services and functions of the RLC sublayer include: Transfer of upper layer PDUs; Error Correction through ARQ (only for AM data transfer); Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer); Re-segmentation of RLC data PDUs (only for AM data transfer); Reordering of RLC data PDUs (only for UM and AM data transfer); Duplicate detection (only for UM and AM data transfer); Protocol error detection (only for AM data transfer); RLC SDU discard (only for UM and AM data transfer); RLC re-establishment.

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6.2.2
-

PDU Structure

Figure 6.2.2-1 below depicts the RLC PDU structure where: The PDU sequence number carried by the RLC header is independent of the SDU sequence number (i.e. PDCP sequence number); A red dotted line indicates the occurrence of segmentation; Because segmentation only occurs when needed and concatenation is done in sequence, the content of an RLC PDU can generally be described by the following relations: {0; 1} last segment of SDUi + [0; n] complete SDUs + {0; 1} first segment of SDUi+n+1 ; or 1 segment of SDUi .

Figure 6.2.2-1: RLC PDU Structure

6.3
6.3.1
-

PDCP Sublayer
Services and Functions

This subclause provides an overview on services, functions and PDU structure provided by the PDCP sublayer.

The main services and functions of the PDCP sublayer for the user plane include: Header compression and decompression: ROHC only; Transfer of user data; In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM; Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM; Retransmission of PDCP SDUs at handover for RLC AM; Ciphering and deciphering; Timer-based SDU discard in uplink. When compared to UTRAN, the lossless DL RLC PDU size change is not required.

NOTE:

The main services and functions of the PDCP for the control plane include: Ciphering and Integrity Protection; Transfer of control plane data.

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6.3.2
-

PDU Structure

Figure 6.3.2-1 below depicts the PDCP PDU structure for user plane data, where: PDCP PDU and PDCP header are octet-aligned; PDCP header can be either 1 or 2 bytes long.

Figure 6.3.2-1: PDCP PDU Structure The structures for control PDCP PDUs and for control plane PDCP data PDUs are specified in [15].

6.4

Void

7
7.1
-

RRC
Services and Functions
Broadcast of System Information related to the non-access stratum (NAS); Broadcast of System Information related to the access stratum (AS); Paging; Establishment, maintenance and release of an RRC connection between the UE and E-UTRAN including: Allocation of temporary identifiers between UE and E-UTRAN; Configuration of signalling radio bearer(s) for RRC connection: Low priority SRB and high priority SRB.

This subclause provides an overview on services and functions provided by the RRC sublayer.

The main services and functions of the RRC sublayer include:

Security functions including key management; Establishment, configuration, maintenance and release of point to point Radio Bearers; Mobility functions including: UE measurement reporting and control of the reporting for inter-cell and inter-RAT mobility; Handover; UE cell selection and reselection and control of cell selection and reselection; Context transfer at handover.

-

Notification for MBMS services; Establishment, configuration, maintenance and release of Radio Bearers for MBMS services;

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QoS management functions; UE measurement reporting and control of the reporting; NAS direct message transfer to/from NAS from/to UE.

7.2
-

RRC protocol states & state transitions
RRC_IDLE: PLMN selection; DRX configured by NAS; Broadcast of system information; Paging; Cell re-selection mobility; The UE shall have been allocated an id which uniquely identifies the UE in a tracking area; No RRC context stored in the eNB.

RRC uses the following states:

-

RRC_CONNECTED: UE has an E-UTRAN-RRC connection; UE has context in E-UTRAN; E-UTRAN knows the cell which the UE belongs to; Network can transmit and/or receive data to/from UE; Network controlled mobility (handover and inter-RAT cell change order to GERAN with NACC); Neighbour cell measurements; At PDCP/RLC/MAC level: UE can transmit and/or receive data to/from network; UE monitors control signalling channel for shared data channel to see if any transmission over the shared data channel has been allocated to the UE; UE also reports channel quality information and feedback information to eNB; DRX period can be configured according to UE activity level for UE power saving and efficient resource utilization. This is under control of the eNB.

7.3

Transport of NAS messages

The AS provides reliable in-sequence delivery of NAS messages in a cell. During handover, message loss or duplication of NAS messages can occur. In E-UTRAN, NAS messages are either concatenated with RRC messages or carried in RRC without concatenation. Upon arrival of concurrent NAS messages for the same UE requiring both concatenation with RRC for the high priority queue and also without concatenation for the lower priority queue, the messages are first queued as necessary to maintain in-sequence delivery. In DL, when an EPS bearer establishment or release procedure is triggered, the NAS message should normally be concatenated with the associated RRC message. When the EPS bearer is modified and when the modification also depends on a modification of the radio bearer, the NAS message and associated RRC message should normally be

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concatenated. Concatenation of DL NAS with RRC message is not allowed otherwise. In uplink concatenation of NAS messages with RRC message is used only for transferring the initial NAS message during connection setup. Initial Direct Transfer is not used in E-UTRAN and no NAS message is concatenated with RRC connection request. Multiple NAS messages can be sent in a single downlink RRC message during EPS bearer establishment or modification. In this case, the order of the NAS messages in the RRC message shall be kept the same as that in the corresponding S1-AP message in order to ensure the in-sequence delivery of NAS messages. NOTE: NAS messages are integrity protected and ciphered by PDCP, in addition to the integrity protection and ciphering performed by NAS.

7.4

System Information

System information is divided into the MasterInformationBlock (MIB) and a number of SystemInformationBlocks (SIBs): MasterInformationBlock defines the most essential physical layer information of the cell required to receive further system information; SystemInformationBlockType1 contains information relevant when evaluating if a UE is allowed to access a cell and defines the scheduling of other system information blocks; SystemInformationBlockType2 contains common and shared channel information; SystemInformationBlockType3 contains cell re-selection information, mainly related to the serving cell; SystemInformationBlockType4 contains information about the serving frequency and intra-frequency neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters); SystemInformationBlockType5 contains information about other E-UTRA frequencies and inter-frequency neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters); SystemInformationBlockType6 contains information about UTRA frequencies and UTRA neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters); SystemInformationBlockType7 contains information about GERAN frequencies relevant for cell re-selection (including cell re-selection parameters for each frequency); SystemInformationBlockType8 contains information about CDMA2000 frequencies and CDMA2000 neighbouring cells relevant for cell re-selection (including cell re-selection parameters common for a frequency as well as cell specific re-selection parameters); SystemInformationBlockType9 contains a home eNB identifier (HNBID); SystemInformationBlockType10 contains an ETWS primary notification; SystemInformationBlockType11 contains an ETWS secondary notification; SystemInformationBlockType12 contains a CMAS warning notification; SystemInformationBlockType13 contains MBMS-related information.

-

-

-

-

The MIB is mapped on the BCCH and carried on BCH while all other SI messages are mapped on the BCCH and dynamically carried on DL-SCH where they can be identified through the SI-RNTI (System Information RNTI). Both the MIB and SystemInformationBlockType1 use a fixed schedule with a periodicity of 40 and 80 ms respectively while the scheduling of other SI messages is flexible and indicated by SystemInformationBlockType1. The eNB may schedule DL-SCH transmissions concerning logical channels other than BCCH in the same subframe as used for BCCH. The minimum UE capability restricts the BCCH mapped to DL-SCH e.g. regarding the maximum rate. The Paging message is used to inform UEs in RRC_IDLE and UEs in RRC_CONNECTED about a system information change.

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System information may also be provided to the UE by means of dedicated signalling e.g. upon handover.

7.5

Void

8
8.1
-

E-UTRAN identities
E-UTRAN related UE identities
C-RNTI: unique identification used for identifying RRC Connection and scheduling; Semi-Persistent Scheduling C-RNTI: unique identification used for semi-persistent scheduling; Temporary C-RNTI: identification used for the random access procedure; TPC-PUSCH-RNTI: identification used for the power control of PUSCH; TPC-PUCCH-RNTI: identification used for the power control of PUCCH; Random value for contention resolution: during some transient states, the UE is temporarily identified with a random value used for contention resolution purposes.

The following E-UTRAN related UE identities are used at cell level:

8.2
-

Network entity related Identities
Globally Unique MME Identity (GUMMEI): used to identify MME globally. The GUMMEI is constructed from the PLMN identity the MME belongs to, the group identity of the MME group the MME belongs to and the MME code (MMEC) of the MME within the MME group. a UE in ECM-IDLE establishing an RRC connection has to provide the GUMMEI of its current MME to the eNB in order for the eNB to fetch the UE context from the MME. Within the S-TMSI, one field contains the code of the MME (MMEC) that allocated the S-TMSI. The code of MME is needed to ensure that the S-TMSI remains unique in a tracking area shared by multiple MMEs.

The following identities are used in E-UTRAN for identifying a specific network entity [25]:

NOTE:

-

E-UTRAN Cell Global Identifier (ECGI): used to identify cells globally. The ECGI is constructed from the PLMN identity the cell belongs to and the Cell Identity (CI) of the cell. The included PLMN is the one given by the first PLMN entry in SIB1, according to [16]. eNB Identifier (eNB ID): used to identify eNBs within a PLMN. The eNB ID is contained within the CI of its cells. Global eNB ID: used to identify eNBs globally. The Global eNB ID is constructed from the PLMN identity the eNB belongs to and the eNB ID. The MCC and MNC are the same as included in the E-UTRAN Cell Global Identifier (ECGI). Tracking Area identity (TAI): used to identify tracking areas. The TAI is constructed from the PLMN identity the tracking area belongs to and the TAC (Tracking Area Code) of the Tracking Area. CSG identity (CSG ID): used to identify a CSG within a PLMN. EPS Bearer ID / E-RAB ID: The value of the E-RAB ID used at S1 and X2 interfaces to identify an E-RAB allocated to the UE is the same as the EPS Bearer ID value used at the Uu interface to identify the associated EPS Bearer (and also used at the NAS layer as defined in [25]).

-

-

The following identities are broadcast in every E-UTRAN cell (SIB1): CI, TAC, CSG ID (if any) and one or more PLMN identities.

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ARQ and HARQ

E-UTRAN provides ARQ and HARQ functionalities. The ARQ functionality provides error correction by retransmissions in acknowledged mode at Layer 2. The HARQ functionality ensures delivery between peer entities at Layer 1.

9.1
-

HARQ principles
N-process Stop-And-Wait; HARQ transmits and retransmits transport blocks; In the downlink: Asynchronous adaptive HARQ; Uplink ACK/NAKs in response to downlink (re)transmissions are sent on PUCCH or PUSCH; PDCCH signals the HARQ process number and if it is a transmission or retransmission; Retransmissions are always scheduled through PDCCH.

The HARQ within the MAC sublayer has the following characteristics:

-

In the uplink: Synchronous HARQ; Maximum number of retransmissions configured per UE (as opposed to per radio bearer); Downlink ACK/NAKs in response to uplink (re)transmissions are sent on PHICH; HARQ operation in uplink is governed by the following principles (summarized in Table 9.1-1): 1) Regardless of the content of the HARQ feedback (ACK or NACK), when a PDCCH for the UE is correctly received, the UE follows what the PDCCH asks the UE to do i.e. perform a transmission or a retransmission (referred to as adaptive retransmission); 2) When no PDCCH addressed to the C-RNTI of the UE is detected, the HARQ feedback dictates how the UE performs retransmissions: NACK: the UE performs a non-adaptive retransmission i.e. a retransmission on the same uplink resource as previously used by the same process; ACK: the UE does not perform any UL (re)transmission and keeps the data in the HARQ buffer. A PDCCH is then required to perform a retransmission i.e. a non-adaptive retransmission cannot follow.

-

Measurement gaps are of higher priority than HARQ retransmissions: whenever an HARQ retransmission collides with a measurement gap, the HARQ retransmission does not take place. Table 9.1-1: UL HARQ Operation
HARQ feedback seen by the UE ACK or NACK ACK or NACK ACK NACK PDCCH seen by the UE New Transmission Retransmission None None UE behaviour New transmission according to PDCCH Retransmission according to PDCCH (adaptive retransmission) No (re)transmission, keep data in HARQ buffer and a PDDCH is required to resume retransmissions Non-adaptive retransmission

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9.2
-

ARQ principles
ARQ retransmits RLC PDUs or RLC PDU segments based on RLC status reports; Polling for RLC status report is used when needed by RLC; RLC receiver can also trigger RLC status report after detecting a missing RLC PDU or RLC PDU segment.

The ARQ within the RLC sublayer has the following characteristics:

9.3

Void

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Mobility

Load balancing is achieved in E-UTRAN with redirection mechanisms (upon RRC establishment, in RRC_CONNECTED and upon RRC release) and through the usage of inter-frequency and inter-RAT absolute priorities and inter-frequency Qoffset parameters. Measurements to be performed by a UE for mobility are classified in at least three measurement types: Intra-frequency E-UTRAN measurements; Inter-frequency E-UTRAN measurements; Inter-RAT measurements for UTRAN and GERAN; Inter-RAT measurements of CDMA2000 HRPD or 1xRTT frequencies.

For each measurement type one or several measurement objects can be defined (a measurement object defines e.g. the carrier frequency to be monitored). For each measurement object one or several reporting configurations can be defined (a reporting configuration defines the reporting criteria). Three reporting criteria are used: event triggered reporting, periodic reporting and event triggered periodic reporting. The association between a measurement object and a reporting configuration is created by a measurement identity (a measurement identity links together one measurement object and one reporting configuration of same RAT). By using several measurement identities (one for each measurement object, reporting configuration pair) it is possible: To associate several reporting configurations to one measurement object and; To associate one reporting configuration to several measurement objects.

The measurements identity is as well used when reporting results of the measurements. Measurement quantities are considered separately for each RAT. Measurement commands are used by E-UTRAN to order the UE to start measurements, modify measurements or stop measurements.

10.1

Intra E-UTRAN

In E-UTRAN RRC_CONNECTED state, network-controlled UE-assisted handovers are performed and various DRX cycles are supported. In E-UTRAN RRC_IDLE state, cell reselections are performed and DRX is supported.

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10.1.1.1

Mobility Management in ECM-IDLE
Cell selection

The principles of PLMN selection in E-UTRA are based on the 3GPP PLMN selection principles. Cell selection is required on transition from EMM_DETACHED to EMM-REGISTERED and from ECM-IDLE or ECMCONNECTED. Cell selection: The UE NAS identifies a selected PLMN and equivalent PLMNs; The UE searches the E-UTRA frequency bands and for each carrier frequency identifies the strongest cell. It reads cell system information broadcast to identify its PLMN(s): The UE may search each carrier in turn (“initial cell selection”) or make use of stored information to shorten the search (“stored information cell selection”).

The UE seeks to identify a suitable cell; if it is not able to identify a suitable cell it seeks to identify an acceptable cell. When a suitable cell is found or if only an acceptable cell is found it camps on that cell and commence the cell reselection procedure: A suitable cell is one for which the measured cell attributes satisfy the cell selection criteria; the cell PLMN is the selected PLMN, registered or an equivalent PLMN; the cell is not barred or reserved and the cell is not part of a tracking area which is in the list of “forbidden tracking areas for roaming”; An acceptable cell is one for which the measured cell attributes satisfy the cell selection criteria and the cell is not barred;

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Transition to RRC_IDLE: On transition from RRC_CONNECTED to RRC_IDLE, a UE should camp on the last cell for which it was in RRC_CONNECTED or a cell/any cell of set of cells or frequency be assigned by RRC in the state transition message. Recovery from out of coverage: The UE should attempt to find a suitable cell in the manner described for stored information or initial cell selection above. If no suitable cell is found on any frequency or RAT the UE should attempt to find an acceptable cell.

10.1.1.2

Cell reselection

UE in RRC_IDLE performs cell reselection. The principles of the procedure are the following: The UE makes measurements of attributes of the serving and neighbour cells to enable the reselection process: There is no need to indicate neighbouring cell in the serving cell system information to enable the UE to search and measure a cell i.e. E-UTRAN relies on the UE to detect the neighbouring cells; For the search and measurement of inter-frequency neighbouring cells, only the carrier frequencies need to be indicated; Measurements may be omitted if the serving cell attribute fulfils particular search or measurement criteria.

Cell reselection identifies the cell that the UE should camp on. It is based on cell reselection criteria which involves measurements of the serving and neighbour cells: Intra-frequency reselection is based on ranking of cells; Inter-frequency reselection is based on absolute priorities where UE tries to camp on highest priority frequency available. Absolute priorities for reselection are provided only by the RPLMN and valid only within the RPLMN; priorities are given by the system information and valid for all UEs in a cell, specific priorities per UE can be signalled in the RRC Connection Release message. A validity time can be associated with UE specific priorities.

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For inter-frequency neighbouring cells, it is possible to indicate layer-specific cell reselection parameters (e.g., layer specific offset). These parameters are common to all neighbouring cells on a frequency; An NCL can be provided by the serving cell to handle specific cases for intra- and inter-frequency neighbouring cells. This NCL contains cell specific cell reselection parameters (e.g., cell specific offset) for specific neighbouring cells; Black lists can be provided to prevent the UE from reselecting to specific intra- and inter-frequency neighbouring cells; Cell reselection can be speed dependent (speed detection based on UTRAN solution); Cell reselection parameters are applicable for all UEs in a cell, but it is possible to configure specific reselection parameters per UE group or per UE.

-

Cell access restrictions apply as for UTRAN, which consist of access class (AC) barring and cell reservation (e.g. for cells "reserved for operator use") applicable for mobiles in RRC_IDLE mode.

10.1.1.3 10.1.1.4 10.1.1.5

Void Void Void

10.1.2

Mobility Management in ECM-CONNECTED

The Intra-E-UTRAN-Access Mobility Support for UEs in ECM-CONNECTED handles all necessary steps for relocation/handover procedures, like processes that precede the final HO decision on the source network side (control and evaluation of UE and eNB measurements taking into account certain UE specific area restrictions), preparation of resources on the target network side, commanding the UE to the new radio resources and finally releasing resources on the (old) source network side. It contains mechanisms to transfer context data between evolved nodes, and to update node relations on C-plane and U-plane. In E-UTRAN RRC_CONNECTED state, network-controlled UE-assisted handovers are performed and various DRX cycles are supported: The UE makes measurements of attributes of the serving and neighbour cells to enable the process: There is no need to indicate neighbouring cell to enable the UE to search and measure a cell i.e. E-UTRAN relies on the UE to detect the neighbouring cells; For the search and measurement of inter-frequency neighbouring cells, at least the carrier frequencies need to be indicated; Network signals reporting criteria for event-triggered and periodical reporting; An NCL can be provided by the serving cell by RRC dedicated signalling to handle specific cases for intra- and inter-frequency neighbouring cells. This NCL contains cell specific measurement parameters (e.g. cell specific offset) for specific neighbouring cells; Black lists can be provided to prevent the UE from measuring specific neighbouring cells.

-

Depending on whether the UE needs transmission/reception gaps to perform the relevant measurements, measurements are classified as gap assisted or non-gap assisted. A non-gap assisted measurement is a measurement on a cell that does not require transmission/reception gaps to allow the measurement to be performed. A gap assisted measurement is a measurement on a cell that does require transmission/reception gaps to allow the measurement to be performed. Gap patterns (as opposed to individual gaps) are configured and activated by RRC.

10.1.2.1

Handover

The intra E-UTRAN HO in RRC_CONNECTED state is UE assisted NW controlled HO, with HO preparation signalling in E-UTRAN:

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Part of the HO command comes from the target eNB and is transparently forwarded to the UE by the source eNB; To prepare the HO, the source eNB passes all necessary information to the target eNB (e.g. E-RAB attributes and RRC context); Both the source eNB and UE keep some context (e.g. C-RNTI) to enable the return of the UE in case of HO failure; UE accesses the target cell via RACH following a contention-free procedure using a dedicated RACH preamble or following a contention-based procedure if dedicated RACH preambles are not available: the UE uses the dedicated preamble until the handover procedure is finished (successfully or unsuccessfully);

-

If the RACH procedure towards the target cell is not successful within a certain time, the UE initiates radio link failure recovery using the best cell; No ROHC context is transferred at handover.

10.1.2.1.1

C-plane handling

The HO procedure is performed without EPC involvement, i.e. preparation messages are directly exchanged between the eNBs. The release of the resources at the source side during the HO completion phase is triggered by the eNB. The figure below depicts the basic handover scenario where neither MME nor Serving Gateway changes:

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UE

Source eNB

Target eNB

MME

Serving

Gateway

0. Area Restriction Provided 1. Measurement Control packet data packet data Legend L3 signalling L1/L2 signalling 3. HO decision Handover Preparation packet data 12. Path Switch Request 13. User Plane update request packet data End Marker 16.Path Switch Request Ack 17. UE Context Release 18. Release Resources 15.User Plane update response Handover Completion 14. Switch DL path Handover Execution 4. Handover Request 5. Admission Control 6. Handover Request Ack DL allocation 7. RRC Conn. Reconf. incl. mobilityControlinformation Deliver buffered and in transit packets to target eNB 8. SN Status Transfer User Data

UL allocation 2. Measurement Reports

Detach from old cell and synchronize to new cell

Data Forwarding

Buffer packets from Source eNB 9. 10. 11. Synchronisation UL allocation + TA for UE

RRC Conn. Reconf. Complete packet data

End Marker

Figure 10.1.2.1.1-1: Intra-MME/Serving Gateway HO Below is a more detailed description of the intra-MME/Serving Gateway HO procedure: 0 The UE context within the source eNB contains information regarding roaming restrictions which where provided either at connection establishment or at the last TA update. 1 The source eNB configures the UE measurement procedures according to the area restriction information. Measurements provided by the source eNB may assist the function controlling the UE's connection mobility. 2 UE is triggered to send MEASUREMENT REPORT by the rules set by i.e. system information, specification etc. 3 Source eNB makes decision based on MEASUREMENT REPORT and RRM information to hand off UE.

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4 The source eNB issues a HANDOVER REQUEST message to the target eNB passing necessary information to prepare the HO at the target side (UE X2 signalling context reference at source eNB, UE S1 EPC signalling context reference, target cell ID, KeNB*, RRC context including the C-RNTI of the UE in the source eNB, ASconfiguration, E-RAB context and physical layer ID of the source cell + MAC for possible RLF recovery). UE X2 / UE S1 signalling references enable the target eNB to address the source eNB and the EPC. The E-RAB context includes necessary RNL and TNL addressing information, and QoS profiles of the E-RABs. 5 Admission Control may be performed by the target eNB dependent on the received E-RAB QoS information to increase the likelihood of a successful HO, if the resources can be granted by target eNB. The target eNB configures the required resources according to the received E-RAB QoS information and reserves a C-RNTI and optionally a RACH preamble. The AS-configuration to be used in the target cell can either be specified independently (i.e. an "establishment") or as a delta compared to the AS-configuration used in the source cell (i.e. a "reconfiguration"). 6 Target eNB prepares HO with L1/L2 and sends the HANDOVER REQUEST ACKNOWLEDGE to the source eNB. The HANDOVER REQUEST ACKNOWLEDGE message includes a transparent container to be sent to the UE as an RRC message to perform the handover. The container includes a new C-RNTI, target eNB security algorithm identifiers for the selected security algorithms, may include a dedicated RACH preamble, and possibly some other parameters i.e. access parameters, SIBs, etc. The HANDOVER REQUEST ACKNOWLEDGE message may also include RNL/TNL information for the forwarding tunnels, if necessary. NOTE: As soon as the source eNB receives the HANDOVER REQUEST ACKNOWLEDGE, or as soon as the transmission of the handover command is initiated in the downlink, data forwarding may be initiated.

Steps 7 to 16 provide means to avoid data loss during HO and are further detailed in 10.1.2.1.2 and 10.1.2.3. 7 The target eNB generates the RRC message to perform the handover, i.e RRCConnectionReconfiguration message including the mobilityControlInformation, to be sent by the source eNB towards the UE. The source eNB performs the necessary integrity protection and ciphering of the message. The UE receives the RRCConnectionReconfiguration message with necessary parameters (i.e. new C-RNTI, target eNB security algorithm identifiers, and optionally dedicated RACH preamble, target eNB SIBs, etc.) and is commanded by the source eNB to perform the HO. The UE does not need to delay the handover execution for delivering the HARQ/ARQ responses to source eNB. 8 The source eNB sends the SN STATUS TRANSFER message to the target eNB to convey the uplink PDCP SN receiver status and the downlink PDCP SN transmitter status of E-RABs for which PDCP status preservation applies (i.e. for RLC AM). The uplink PDCP SN receiver status includes at least the PDCP SN of the first missing UL SDU and may include a bit map of the receive status of the out of sequence UL SDUs that the UE needs to retransmit in the target cell, if there are any such SDUs. The downlink PDCP SN transmitter status indicates the next PDCP SN that the target eNB shall assign to new SDUs, not having a PDCP SN yet. The source eNB may omit sending this message if none of the E-RABs of the UE shall be treated with PDCP status preservation. 9 After receiving the RRCConnectionReconfiguration message including the mobilityControlInformation , UE performs synchronisation to target eNB and accesses the target cell via RACH, following a contention-free procedure if a dedicated RACH preamble was indicated in the mobilityControlInformation, or following a contention-based procedure if no dedicated preamble was indicated. UE derives target eNB specific keys and configures the selected security algorithms to be used in the target cell. 10 The target eNB responds with UL allocation and timing advance. 11 When the UE has successfully accessed the target cell, the UE sends the RRCConnectionReconfigurationComplete message (C-RNTI) to confirm the handover, along with an uplink Buffer Status Report, whenever possible, to the target eNB to indicate that the handover procedure is completed for the UE. The target eNB verifies the C-RNTI sent in the RRCConnectionReconfigurationComplete message. The target eNB can now begin sending data to the UE. 12 The target eNB sends a PATH SWITCH message to MME to inform that the UE has changed cell. 13 The MME sends an UPDATE USER PLANE REQUEST message to the Serving Gateway. 14 The Serving Gateway switches the downlink data path to the target side. The Serving gateway sends one or more "end marker" packets on the old path to the source eNB and then can release any U-plane/TNL resources towards the source eNB.

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15 Serving Gateway sends an UPDATE USER PLANE RESPONSE message to MME. 16 The MME confirms the PATH SWITCH message with the PATH SWITCH ACKNOWLEDGE message. 17 By sending UE CONTEXT RELEASE, the target eNB informs success of HO to source eNB and triggers the release of resources by the source eNB. The target eNB sends this message after the PATH SWITCH ACKNOWLEDGE message is received from the MME. 18 Upon reception of the UE CONTEXT RELEASE message, the source eNB can release radio and C-plane related resources associated to the UE context. Any ongoing data forwarding may continue.

10.1.2.1.2

U-plane handling

The U-plane handling during the Intra-E-UTRAN-Access mobility activity for UEs in ECM-CONNECTED takes the following principles into account to avoid data loss during HO: During HO preparation U-plane tunnels can be established between the source eNB and the target eNB. There is one tunnel established for uplink data forwarding and another one for downlink data forwarding for each E-RAB for which data forwarding is applied. During HO execution, user data can be forwarded from the source eNB to the target eNB. The forwarding may take place in a service and deployment dependent and implementation specific way. Forwarding of downlink user data from the source to the target eNB should take place in order as long as packets are received at the source eNB from the EPC or the source eNB buffer has not been emptied.

-

During HO completion: The target eNB sends a PATH SWITCH message to MME to inform that the UE has gained access and MME sends a USER PLANE UPDATE REQUEST message to the Serving Gateway, the U-plane path is switched by the Serving Gateway from the source eNB to the target eNB. The source eNB should continue forwarding of U-plane data as long as packets are received at the source eNB from the Serving Gateway or the source eNB buffer has not been emptied.

-

For RLC-AM bearers: During normal HO not involving Full Configuration: For in-sequence delivery and duplication avoidance, PDCP SN is maintained on a bearer basis and the source eNB informs the target eNB about the next DL PDCP SN to allocate to a packet which does not have a PDCP sequence number yet (either from source eNB or from the Serving Gateway). For security synchronisation, HFN is also maintained and the source eNB provides to the target one reference HFN for the UL and one for the DL i.e. HFN and corresponding SN. In both the UE and the target eNB, a window-based mechanism is needed for duplication detection. The occurrence of duplicates over the air interface in the target eNB is minimised by means of PDCP SN based reporting at the target eNB by the UE. In uplink, the reporting is optionally configured on a bearer basis by the eNB and the UE should first start by transmitting those reports when granted resources in the target eNB. In downlink, the eNB is free to decide when and for which bearers a report is sent and the UE does not wait for the report to resume uplink transmission. The target eNB re-transmits and prioritizes all downlink PDCP SDUs forwarded by the source eNB (i.e. the target eNB should send data with PDCP SNs from X2 before sending data from S1), with the exception of PDCP SDUs of which the reception was acknowledged through PDCP SN based reporting by the UE. The UE re-transmits in the target eNB all uplink PDCP SDUs starting from the first PDCP SDU following the last consecutively confirmed PDCP SDU i.e. the oldest PDCP SDU that has not been acknowledged at RLC in the source, excluding the PDCP SDUs of which the reception was acknowledged through PDCP SN based reporting by the target.

-

-

-

-

During HO involving Full Configuration:

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- The following description below for RLC-UM bearers also applies for RLC-AM bearers. Data loss may happen.

For RLC-UM bearers: The PDCP SN and HFN are reset in the target eNB. No PDCP SDUs are retransmitted in the target eNB. The target eNB prioritize all downlink PDCP SDUs forwarded by the source eNB if any (i.e. the target eNB should send data with PDCP SNs from X2 before sending data from S1),. The UE PDCP entity does not attempt to retransmit any PDCP SDU in the target cell for which transmission had been completed in the source cell. Instead UE PDCP entity starts the transmission with other PDCP SDUs.

10.1.2.2

Path Switch

After the downlink path is switched at the Serving GW downlink packets on the forwarding path and on the new direct path may arrive interchanged at the target eNB. The target eNodeB should first deliver all forwarded packets to the UE before delivering any of the packets received on the new direct path. The method employed in the target eNB to enforce the correct delivery order of packets is outside the scope of the standard. In order to assist the reordering function in the target eNB, the Serving GW shall send one or more "end marker" packets on the old path immediately after switching the path for each E-RAB of the UE. The "end marker" packet shall not contain user data. The "end marker" is indicated in the GTP header. After completing the sending of the tagged packets the GW shall not send any further user data packets via the old path. Upon receiving the "end marker" packets, the source eNB shall, if forwarding is activated for that bearer, forward the packet toward the target eNB. On detection of an "end marker" the target eNB shall discard the end marker packet and initiate any necessary processing to maintain in sequence delivery of user data forwarded over X2 interface and user data received from the serving GW over S1 as a result of the path switch. On detection of the "end marker", the target eNB may also initiate the release of the data forwarding resource. However, the release of the data forwarding resource is implementation dependent and could also be based on other mechanisms (e.g. timer-based mechanism). EPC may change the uplink end-point of the tunnels with Path Switch procedure. However, the EPC should keep the old GTP tunnel end-point(s) sufficiently long time in order to minimise the probability of packet losses and avoid unintentional release of respective E-RAB(s).

10.1.2.3
10.1.2.3.1

Data forwarding
For RLC-AM DRBs

Upon handover, the source eNB may forward in order to the target eNB all downlink PDCP SDUs with their SN that have not been acknowledged by the UE. In addition, the source eNB may also forward without a PDCP SN fresh data arriving over S1 to the target eNB. NOTE: Target eNB does not have to wait for the completion of forwarding from the source eNB before it begins transmitting packets to the UE.

The source eNB discards any remaining downlink RLC PDUs. Correspondingly, the source eNB does not forward the downlink RLC context to the target eNB. NOTE: Source eNB does not need to abort on going RLC transmissions with the UE as it starts data forwarding to the target eNB.

Upon handover, the source eNB forwards to the Serving Gateway the uplink PDCP SDUs successfully received insequence until the sending of the Status Transfer message to the target eNB. Then at that point of time the source eNB

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stops delivering uplink PDCP SDUs to the S-GW and shall discard any remaining uplink RLC PDUs. Correspondingly, the source eNB does not forward the uplink RLC context to the target eNB. Then the source eNB shall either: discard the uplink PDCP SDUs received out of sequence if the source eNB has not accepted the request from the target eNB for uplink forwarding or if the target eNB has not requested uplink forwarding for the bearer during the Handover Preparation procedure, forward to the target eNB the uplink PDCP SDUs received out of sequence if the source eNB has accepted the request from the target eNB for uplink forwarding for the bearer during the Handover Preparation procedure.

-

The PDCP SN of forwarded SDUs is carried in the "PDCP PDU number" field of the GTP-U extension header. The target eNB shall use the PDCP SN if it is available in the forwarded GTP-U packet. For normal HO in-sequence delivery of upper layer PDUs during handover is based on a continuous PDCP SN and is provided by the "in-order delivery and duplicate elimination" function at the PDCP layer: in the downlink, the "in-order delivery and duplicate elimination" function at the UE PDCP layer guarantees insequence delivery of downlink PDCP SDUs; in the uplink, the "in-order delivery and duplicate elimination" function at the target eNB PDCP layer guarantees in-sequence delivery of uplink PDCP SDUs.

After a normal handover, when the UE receives a PDCP SDU from the target eNB, it can deliver it to higher layer together with all PDCP SDUs with lower SNs regardless of possible gaps. For handovers involving Full Configuration, the source eNB behaviour is unchanged from the description above. The target eNB may not send PDCP SDUs for which delivery was attempted by the source eNB. The target eNB identifies these by the presence of the PDCP SN in the forwarded GTP-U packet and discards them. After a Full Configuration handover, when the UE delivers received PDCP SDU from the source cell to the higher layer regardless of possible gaps. UE discards uplink PDCP SDUs for which transmission was attempted and retransmission of these over the target cell is not possible.

10.1.2.3.2

For RLC-UM DRBs

Upon handover, the source eNB does not forward to the target eNB downlink PDCP SDUs for which transmission had been completed in the source cell. PDCP SDUs that have not been transmitted may be forwarded. In addition, the source eNB may forward fresh downlink data arriving over S1 to the target eNB. The source eNB discards any remaining downlink RLC PDUs. Correspondingly, the source eNB does not forward the downlink RLC context to the target eNB. Upon handover, the source eNB forwards all uplink PDCP SDUs successfully received to the Serving Gateway (i.e. including the ones received out of sequence) and discards any remaining uplink RLC PDUs. Correspondingly, the source eNB does not forward the uplink RLC context to the target eNB.

10.1.2.3.3

SRB handling

With respect to SRBs, the following principles apply at HO: No forwarding or retransmissions of RRC messages in the target; The PDCP SN and HFN are reset in the target.

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10.1.2.4 10.1.2.5 10.1.2.6 10.1.2.7

Void Void Void Timing Advance

In RRC_CONNECTED, the eNB is responsible for maintaining the timing advance. In some cases (e.g. during DRX), the timing advance is not necessarily always maintained and the MAC sublayer knows if the L1 is synchronised and which procedure to use to start transmitting in the uplink: as long as the L1 is non-synchronised, uplink transmission can only take place on PRACH.

For one UE, cases where the UL synchronisation status moves from "synchronised" to "non-synchronised" include: Expiration of a timer; Non-synchronised handover;

The value of the timer is either UE specific and managed through dedicated signalling between the UE and the eNB, or cell specific and indicated via broadcast information. In both cases, the timer is normally restarted whenever a new timing advance is given by the eNB: restarted to a UE specific value if any; or restarted to a cell specific value otherwise.

Upon DL data arrival or for positioning purpose, dedicated signature on PRACH can be allocated by the eNB to UE. When a dedicated signature on PRACH is allocated, the UE shall perform the corresponding random access procedure regardless of its L1 synchronisation status. Timing advance updates are signalled by the eNB to the UE in MAC PDUs addressed via C-RNTI.

10.1.3

Measurements

Measurements to be performed by a UE for intra/inter-frequency mobility can be controlled by E-UTRAN, using broadcast or dedicated control. In RRC_IDLE state, a UE shall follow the measurement parameters defined for cell reselection specified by the E-UTRAN broadcast. The use of dedicated measurement control for RRC_IDLE state is possible through the provision of UE specific priorities (see sub-clause 10.2.4). In RRC_CONNECTED state, a UE shall follow the measurement configurations specified by RRC directed from the E-UTRAN (e.g. as in UTRAN MEASUREMENT_CONTROL). Intra-frequency neighbour (cell) measurements and inter-frequency neighbour (cell) measurements are defined as follows: Intra-frequency neighbour (cell) measurements: Neighbour cell measurements performed by the UE are intrafrequency measurements when the current and target cell operates on the same carrier frequency. The UE shall be able to carry out such measurements without measurement gaps. Inter-frequency neighbour (cell) measurements: Neighbour cell measurements performed by the UE are interfrequency measurements when the neighbour cell operates on a different carrier frequency, compared to the current cell. The UE should not be assumed to be able to carry out such measurements without measurement gaps.

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Whether a measurement is non gap assisted or gap assisted depends on the UE's capability and current operating frequency. The UE determines whether a particular cell measurement needs to be performed in a transmission/reception gap and the scheduler needs to know whether gaps are needed: Same carrier frequency and cell bandwidths (Scenario A): an intra-frequency scenario; not measurement gap assisted.

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Same carrier frequency, bandwidth of the target cell smaller than the bandwidth of the current cell (Scenario B): an intra-frequency scenario; not measurement gap assisted. Same carrier frequency, bandwidth of the target cell larger than the bandwidth of the current cell (Scenario C): an intra-frequency scenario; not measurement gap assisted. Different carrier frequencies, bandwidth of the target cell smaller than the bandwidth of the current cell and bandwidth of the target cell within bandwidth of the current cell (Scenario D): an inter-frequency scenario; measurement gap-assisted scenario. Different carrier frequencies, bandwidth of the target cell larger than the bandwidth of the current cell and bandwidth of the current cell within bandwidth of the target cell (Scenario E): an inter-frequency scenario; measurement gap-assisted scenario. Different carrier frequencies and non-overlapping bandwidth, (Scenario F): an inter-frequency scenario; measurement gap-assisted scenario.

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Figure 10.1.3-1: Inter and Intra-frequency measurements scenarios Measurement gaps patterns are configured and activated by RRC.

10.1.3.1

Intra-frequency neighbour (cell) measurements

In a system with frequency reuse = 1, mobility within the same frequency layer (i.e. between cells with the same carrier frequency) is predominant. Good neighbour cell measurements are needed for cells that have the same carrier frequency as the serving cell in order to ensure good mobility support and easy network deployment. Search for neighbour cells with the same carrier frequency as the serving cell, and measurements of the relevant quantities for identified cells are needed. NOTE: To avoid UE activity outside the DRX cycle, the reporting criteria for neighbour cell measurements should match the used DRX cycle.

10.1.3.2

Inter-frequency neighbour (cell) measurements

Regarding mobility between different frequency layers (i.e. between cells with a different carrier frequency), UE may need to perform neighbour cell measurements during DL/UL idle periods that are provided by DRX or packet scheduling (i.e. gap assisted measurements).

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10.1.4
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Paging and C-plane establishment

Paging groups (where multiple UEs can be addressed) are used on PDCCH: Precise UE identity is found on PCH; DRX configurable via BCCH and NAS; Only one subframe allocated per paging interval per UE; The network may divide UEs to different paging occasions in time; There is no grouping within paging occasion; One paging RNTI for PCH.

10.1.5
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Random Access Procedure

The random access procedure is characterized by: Common procedure for FDD and TDD; One procedure irrespective of cell size;

The random access procedure is performed for the following six events: Initial access from RRC_IDLE; RRC Connection Re-establishment procedure; Handover; DL data arrival during RRC_CONNECTED requiring random access procedure; E.g. when UL synchronisation status is “non-synchronised”;

UL data arrival during RRC_CONNECTED requiring random access procedure; E.g. when UL synchronisation status is "non-synchronised" or there are no PUCCH resources for SR available.

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For positioning purpose during RRC_CONNECTED requiring random access procedure; E.g. when timing advance is needed for UE positioning;

Furthermore, the random access procedure takes two distinct forms: Contention based (applicable to first five events); Non-contention based (applicable to only handover, DL data arrival and positioning).

Normal DL/UL transmission can take place after the random access procedure.

10.1.5.1

Contention based random access procedure

The contention based random access procedure is outlined on Figure 10.1.5.1-1 below:

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UE

eNB

1

Random Access Preamble

Random Access Response

2

3

Scheduled Transmission

Contention Resolution

4

Figure 10.1.5.1-1: Contention based Random Access Procedure The four steps of the contention based random access procedures are: 1) Random Access Preamble on RACH in uplink: There are two possible groups defined and one is optional. If both groups are configured the size of message 3 and the pathloss are used to determine which group a preamble is selected from. The group to which a preamble belongs provides an indication of the size of the message 3 and the radio conditions at the UE. The preamble group information along with the necessary thresholds are broadcast on system information.

2) Random Access Response generated by MAC on DL-SCH: Semi-synchronous (within a flexible window of which the size is one or more TTI) with message 1; No HARQ; Addressed to RA-RNTI on PDCCH; Conveys at least RA-preamble identifier, Timing Alignment information, initial UL grant and assignment of Temporary C-RNTI (which may or may not be made permanent upon Contention Resolution); Intended for a variable number of UEs in one DL-SCH message.

3) First scheduled UL transmission on UL-SCH: Uses HARQ; Size of the transport blocks depends on the UL grant conveyed in step 2 and is at least 80 bits. For initial access: Conveys the RRC Connection Request generated by the RRC layer and transmitted via CCCH; Conveys at least NAS UE identifier but no NAS message; RLC TM: no segmentation;

For RRC Connection Re-establishment procedure: Conveys the RRC Connection Re-establishment Request generated by the RRC layer and transmitted via CCCH; RLC TM: no segmentation; Does not contain any NAS message.

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After handover, in the target cell: Conveys the ciphered and integrity protected RRC Handover Confirm generated by the RRC layer and transmitted via DCCH; Conveys the C-RNTI of the UE (which was allocated via the Handover Command); Includes an uplink Buffer Status Report when possible.

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For other events: Conveys at least the C-RNTI of the UE.

4) Contention Resolution on DL: Early contention resolution shall be used i.e. eNB does not wait for NAS reply before resolving contention Not synchronised with message 3; HARQ is supported; Addressed to: The Temporary C-RNTI on PDCCH for initial access and after radio link failure; The C-RNTI on PDCCH for UE in RRC_CONNECTED;

HARQ feedback is transmitted only by the UE which detects its own UE identity, as provided in message 3, echoed in the Contention Resolution message; For initial access and RRC Connection Re-establishment procedure, no segmentation is used (RLC-TM).

The Temporary C-RNTI is promoted to C-RNTI for a UE which detects RA success and does not already have a CRNTI; it is dropped by others. A UE which detects RA success and already has a C-RNTI, resumes using its C-RNTI.

10.1.5.2

Non-contention based random access procedure

The non-contention based random access procedure is outlined on Figure 10.1.5.2-1 below:
UE eNB

0

RA Preamble assignment

Random Access Preamble

1

2

Random Access Response

Figure 10.1.5.2-1: Non-contention based Random Access Procedure The three steps of the non-contention based random access procedures are: 0) Random Access Preamble assignment via dedicated signalling in DL: eNB assigns to UE a non-contention Random Access Preamble (a Random Access Preamble not within the set sent in broadcast signalling). Signalled via:

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HO command generated by target eNB and sent via source eNB for handover; PDCCH in case of DL data arrival or positioning.

1) Random Access Preamble on RACH in uplink: UE transmits the assigned non-contention Random Access Preamble.

2) Random Access Response on DL-SCH: Semi-synchronous (within a flexible window of which the size is two or more TTIs) with message 1; No HARQ; Addressed to RA-RNTI on PDCCH; Conveys at least: Timing Alignment information and initial UL grant for handover; Timing Alignment information for DL data arrival; RA-preamble identifier. Intended for one or multiple UEs in one DL-SCH message.

10.1.5.3

Interaction model between L1 and L2/3 for Random Access Procedure

Random access procedure described above is modelled in Figure 10.1.5.3-1 below from L1 and L2/3 interaction point of view. L2/L3 receives indication from L1 whether ACK is received or DTX is detected after indication of Random Access Preamble transmission to L1. L2/3 indicates L1 to transmit first scheduled UL transmission (RRC Connection Request in case of initial access) if necessary or Random Access Preamble based on the indication from L1.

Figure 10.1.5.3-1: Interaction model between L1 and L2/3 for Random Access Procedure

10.1.6
-

Radio Link Failure

Two phases governs the behaviour associated to radio link failure as shown on Figure 10.1.6-1: First phase: started upon radio problem detection; leads to radio link failure detection; no UE-based mobility; based on timer or other (e.g. counting) criteria (T1).

Second Phase: started upon radio link failure detection or handover failure; leads to RRC_IDLE;

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UE-based mobility; Timer based (T2).

Figure 10.1.6-1: Radio Link Failure Table 10.1.6-1 below describes how mobility is handled with respect to radio link failure: Table 10.1.6-1: Mobility and Radio Link Failure
Cases First Phase Second Phase T2 expired

UE returns to the same cell Continue as if no radio Activity is resumed by means Go via RRC_IDLE problems occurred of explicit signalling between UE and eNB UE selects a different cell N/A Activity is resumed by means Go via RRC_IDLE from the same eNB of explicit signalling between UE and eNB UE selects a cell of a N/A Activity is resumed by means Go via RRC_IDLE prepared eNB (NOTE) of explicit signalling between UE and eNB UE selects a cell of a N/A Go via RRC_IDLE Go via RRC_IDLE different eNB that is not prepared (NOTE) NOTE: a prepared eNB is an eNB which has admitted the UE during an earlier executed HO preparation phase.

In the Second Phase, in order to resume activity and avoid going via RRC_IDLE when the UE returns to the same cell or when the UE selects a different cell from the same eNB, or when the UE selects a cell from a different eNB, the following procedure applies: The UE stays in RRC_CONNECTED; The UE accesses the cell through the random access procedure; The UE identifier used in the random access procedure for contention resolution (i.e. C-RNTI of the UE in the cell where the RLF occurred + physical layer identity of that cell + MAC based on the keys of that cell) is used by the selected eNB to authenticate the UE and check whether it has a context stored for that UE: If the eNB finds a context that matches the identity of the UE, it indicates to the UE that its connection can be resumed; If the context is not found, RRC connection is released and UE initiates procedure to establish new RRC connection. In this case UE is required to go via RRC_IDLE.

10.1.7

Radio Access Network Sharing

E-UTRAN shall support radio access network sharing based on support for multi-to-multi relationship between EUTRAN nodes and EPC nodes (S1-flex). If the E-UTRAN is shared by multiple operators, the system information broadcasted in each shared cell contains the PLMN-id of each operator (up to 6) and a single tracking area code (TAC) valid within all the PLMNs sharing the radio access network resources.

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The UE shall be able to read up to 6 PLMN-ids, to select one of the PLMN-ids at initial attachment and to indicate this PLMN-id to the E-UTRAN in subsequent instances of the Random Access procedures (e.g. as defined in subclause 10.1.5). The E-UTRAN shall select an appropriate MME for the PLMN indicated by the UE. Once attached to an MME, the UE shall be able to indicate the allocated MME in subsequent instances of the Random Access procedures. The indication of the allocated MMEC is contained in the temporary UE identity. Handling of area restrictions for UE in ECM-CONNECTED shall follow the principles specified in sub-clause 10.4.

10.1.8

Handling of Roaming and Area Restrictions for UEs in ECMCONNECTED

Handling of roaming/area restrictions and handling of subscription specific preferences in ECM-CONNECTED is performed in the eNB based on information provided by the EPC over the S1 interface.

10.2

Inter RAT

Service-based redirection between GERAN / UTRAN and E-UTRAN is supported in both directions. This should not require inter-RAT reporting in RRC CONNECTION REQUEST.

10.2.1
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Cell reselection

A UE in RRC_IDLE performs cell reselection. The principles of this procedure are as follows: The UE makes measurements of attributes of the serving and neighbour cells to enable the reselection process: For a UE to search and measure neighbouring GERAN cells, the ARFCNs of the BCCH carriers need to be indicated in the serving cell system information (i.e., an NCL). The NCL does not contain BSICs or cell specific offsets and Qrxlevmin is given per frequency band. For a UE to search and measure neighbouring UTRAN cells, the serving cell can indicate an NCL containing a list of carrier frequencies and scrambling codes. Measurements may be omitted if the serving cell attribute fulfils particular search or measurement criteria.

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Cell reselection identifies the cell that the UE should camp on. It is based on cell reselection criteria which involves measurements of the serving and neighbour cells: Inter-RAT reselection is based on absolute priorities where UE tries to camp on highest priority RAT available. Absolute priorities for inter-RAT reselection are provided only by the RPLMN and valid only within the RPLMN; priorities are given by the system information and valid for all UEs in a cell, specific priorities per UE can be signalled in the RRC Connection Release message. A validity time can be associated with UE specific priorities. It should be possible to prevent the UE from reselecting to specific detected neighbouring cells; The UE is allowed to "leave" the source E-UTRAN cell to read the target GERAN cell broadcast, in order to determine its "suitability", prior to completing the cell reselection; Cell reselection can be speed dependent (speed detection based on UTRAN solution);

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Cell access restrictions apply as for UTRAN, which consist of access class (AC) barring and cell reservation (e.g. for cells "reserved for operator use") applicable for mobiles in RRC_IDLE mode. When performing cell reselection while the UE is camped on another RAT, the principles of this procedure are as follows: The UE measures attributes of the E-UTRA neighbouring cells: Only the carrier frequencies need to be indicated to enable the UE to search and measure E-UTRA neighbouring cells;

Cell reselection identifies the cell that the UE should camp on. It is based on cell reselection criteria which involves measurements of the serving and neighbour cells:

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For E-UTRA neighbouring cells, there is no need to indicate cell-specific cell reselection parameters i.e. these parameters are common to all neighbouring cells on an E-UTRA frequency;

Cell reselection parameters are applicable to all UEs in a cell, but it is possible to configure specific reselection parameters per UE group or per UE. It should be possible to prevent the UE from reselecting to specific detected neighbouring cells.

10.2.2

Handover

Inter RAT HO is designed so that changes to GERAN and UTRAN are minimised. This can be done by following the principles specified for GERAN to/from UTRAN intersystem HO. In particular the following principles are applied to E-UTRAN Inter RAT HO design: 1. Inter RAT HO is network controlled through source access system. The source access system decides about starting the preparation and provides the necessary information to the target system in the format required by the target system. That is, the source system adapts to the target system. The actual handover execution is decided in the source system. 2. Inter RAT HO is backwards handover, i.e. radio resources are prepared in the target 3GPP access system before the UE is commanded by the source 3GPP access system to change to the target 3GPP access system. 3. To enable backwards handover, and while RAN level interfaces are not available, a control interface exists in CN level. In Inter RAT HO involving E-UTRAN access, this interface is between 2G/3G SGSN and corresponding MME/Serving Gateway. 4. The target access system will be responsible for giving exact guidance for the UE on how to make the radio access there (this includes radio resource configuration, target cell system information etc.). This information is given during the handover preparation and should be transported completely transparently through the source access system to the UE. 5. Mechanisms for avoiding or mitigating the loss of user data (i.e. forwarding) can be used until the 3GPP Anchor determines that it can send DL U-plane data directly to the target system. 6. The handover procedure should not require any UE to CN signalling in order for data to start to flow in the target system. This requires that the security context, UE capability context and QoS context is transferred (or translated) within the network between source and target system. 7. Similar handover procedure should apply for handovers of both real time and non-real time services. 8. Similar handover procedure should apply for both Inter RAT Handover and intra-LTE Handover with EPC node change. 9. Network controlled mobility is supported even if no prior UE measurements have been performed on the target cell and/or frequency i.e. “blind HO” is supported.

10.2.2a Inter-RAT cell change order to GERAN with NACC
For interworking towards GERAN, inter-RAT cell change order with NACC is supported even if no prior UE measurements have been performed on the system i.e. “blind NACC” is supported.

10.2.2b Inter-RAT handovers from E-UTRAN
10.2.2b.1
10.2.2b.1.1

Data forwarding
For RLC-AM bearers

Upon handover, the eNB may forward all downlink PDCP SDUs that have not been acknowledged by the UE, or all downlink PDCP SDUs that have not been transmitted to the UE, to the target node. In addition, the eNB may forward fresh data arriving over S1 to the target node. NOTE: Any assigned PDCP SNs are not forwarded because of PDCP reset.

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NOTE:

Target node does not have to wait for the completion of forwarding from the eNB before it begins transmitting packets to the UE.

The eNB discards any remaining downlink RLC PDUs. Upon handover, all successfully received PDCP SDUs are delivered to the upper layers in the UE. NOTE: eNB does not need to abort ongoing RLC transmissions with the UE as it starts data forwarding to the target node.

Upon handover, the eNB may forward uplink PDCP SDUs successfully received to the Serving Gateway and shall discard any remaining uplink RLC PDUs. Correspondingly, the eNB does not forward the downlink and uplink RLC context. For the uplink, the UE transmits over the target RAT from the first PDCP SDU for which transmission has not been attempted in the source cell. In-sequence delivery of upper layer PDUs during handover is not guaranteed.

10.2.2b.1.2

For RLC-UM bearers

Upon handover, the eNB does not forward to the target node downlink PDCP SDUs for which transmission had been completed in the source cell. PDCP SDUs that have not been transmitted may be forwarded. In addition, the eNB may forward fresh data arriving over S1 to the target node. The eNB discards any remaining downlink RLC PDUs. Upon handover, all successfully received PDCP SDUs are delivered to the upper layers in the UE. Upon handover, the eNB may forward all uplink PDCP SDUs successfully received to the Serving Gateway and discards any remaining uplink RLC PDUs. For the uplink, the UE transmits over the target RAT from the first PDCP SDU for which transmission has not been attempted in the source cell. Correspondingly, the eNB does not forward the downlink and uplink RLC context.

10.2.3
10.2.3.1

Measurements
Inter-RAT handovers from E-UTRAN

Measurements to be performed by a UE for inter-RAT mobility can be controlled by E-UTRAN, using broadcast or dedicated control. In RRC_CONNECTED state, a UE shall follow the measurement parameters specified by RRC directed from the E-UTRAN (e.g. as in UTRAN MEASUREMENT_CONTROL). UE performs inter-RAT neighbour cell measurements during DL/UL idle periods that are provided by the network through suitable DRX/DTX period or packet scheduling if necessary.

10.2.3.2

Inter-RAT handovers to E-UTRAN

From UTRAN, UE performs E-UTRAN measurements by using idle periods created by compressed mode (CELL_DCH) or DRX (other states except CELL_FACH). From GERAN, E-UTRAN measurements are performed in the same way as WCDMA measurements for handover to UTRAN: E-UTRAN measurements are performed in GSM idle frames in a time multiplexed manner. However, it should be discussed with GERAN how to ensure that inter-RAT measurements do not take too much measurement time, while the requested 3GPP inter-RAT measurements can be performed well enough. Design constraints of 3GPP inter-RAT measurements should be considered when L1 details of E-UTRAN concept are defined.

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10.2.3.3

Inter-RAT cell reselection from E-UTRAN

In RRC_IDLE state, a UE shall follow the measurement parameters specified by the E-UTRAN broadcast (as in UTRAN SIB). The use of dedicated measurement control is possible through the provision of UE specific priorities (see sub-clause 10.2.4).

10.2.3.4

Limiting measurement load at UE

Introduction of E-UTRA implies co-existence of various UE capabilities. Each UE may support different combinations of RATs, e.g., E-UTRA, UTRA, GSM, and non-3GPP RATs, and different combinations of frequency bands, e.g., 800 MHz, 1.7 GHz, 2 GHZ, etc. Despite such heterogeneous environment, the measurement load at UE should be minimised. To limit the measurement load and the associated control load: E-UTRAN can configure the RATs to be measured by UE; The number of measurement criteria (event and periodic reporting criteria) should be limited (as in TS 25.133 subclause 8.3.2 [7]); E-UTRAN should be aware of the UE capabilities for efficient measurement control, to prevent unnecessary waking up of the measurement entity; Blind HO (i.e., HO without measurement reports from UE) is possible.

10.2.4

Network Aspects

Inter-frequency/inter-RAT UE based mobility relies on a “priority based scheme”, where the network configures a list of RATs/frequencies to be taken as basis for UE’s inter-frequency/inter-RAT cell reselection decisions in priority order. E-UTRAN cells can enable inter-frequency/inter-RAT cell reselection by broadcasting a common priority valid for all UEs in a given cell in addition to other inter-frequency/inter-RAT information. NOTE: The same principles apply in UTRAN.

These common priorities can be overwritten by E-UTRAN through dedicated signalling to individual UEs at RRC_CONNECTED to RRC_IDLE transition. NOTE: In order to have consistent inter-RAT operation, the same principles apply to inter-RAT reselection to EUTRAN. For UTRAN this includes also the transitions within RRC_CONNECTED state from CELL_DCH to CELL_PCH and URA_PCH.

Setting dedicated priorities by E-UTRAN can be based on subscription related information provided by the MME. NOTE: The same principle have been taken as a working assumption in UTRAN (awaiting for SA2 decision on feasibility of providing subscription related information by the CN).

10.2.5

CS fallback

CS fallback can be performed via different options. The following table summarize the various CS fallback options per RAT, necessary UE capabilities and FGI index which should be set to ‘1’. The meaning of FGI index is specified in [16, Annex B]

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Table 10.2.5-1: CS fallback options
UE Capability FGI Index (NOTE 1) Mandatory for UEs supporting CS fallback to UMTS RRC Connection Release with Rel-9 (NOTE 1) Redirection with Sys Info e-RedirectionUTRA PS handover with DRB(s) Rel-8 (NOTE 1) FGI8, FGI22 Mandatory for UEs supporting CS fallback to UMTS CS fallback to RRC Connection Release with Rel-8 (NOTE 2) GSM Redirection without Sys Info Mandatory for UEs supporting CS fallback to GSM RRC Connection Release with Rel-9 (NOTE 2) Redirection with Sys Info Mandatory for UEs supporting CS fallback to GSM Cell change order without Rel-8 (NOTE 2) FGI10 NACC Mandatory for UEs supporting CS fallback to GSM Cell change order with NACC Rel-8 (NOTE 2) FGI10 Mandatory for UEs supporting CS fallback to GSM PS handover Rel-8 (NOTE 2) interRAT-PS-HOToGERAN NOTE 1: All CS fallback to UMTS capable UE shall indicate that it supports UTRA FDD or TDD and supported band list in the UE capability. NOTE 2: All CS fallback to GSM capable UE shall indicate that it supports GERAN and supported band list in the UE capability. NOTE 3: The measurement may be performed before any of the above CS fallback solution is triggered to select the target cell or frequency layer more accurately based on eNB decision. eNB may trigger any of above CS fallback solutions blindly. Target RAT CS fallback to UMTS Solutions RRC Connection Release with Redirection without Sys Info Release Rel-8

10.3
10.3.1

Mobility between E-UTRAN and Non-3GPP radio technologies
UE Capability Configuration

A UE shall be able to communicate with the E-UTRAN about its radio access capability, such as the system (including the release and frequency band) it supports and it’s receive and transmit capabilities (single/dual radio, dual receiver). UE shall transfer its capability about other radio technologies over E-UTRAN using the same procedure used to carry its E-UTRAN radio capability.

10.3.2

Mobility between E-UTRAN and cdma2000 network

This section describes the E-UTRAN mechanisms to support idle and active mode mobility between E-UTRAN and cdma2000 HRPD or 1xRTT. The overall system is described in [17].

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10.3.2.1

Tunnelling of cdma2000 Messages over E-UTRAN between UE and cdma2000 Access Nodes

In order to efficiently support handover procedures when on E-UTRAN with a cdma2000 target system, cdma2000 messages are sent transparently to the target system over the E-UTRAN, with the eNB and MME acting as relay points. To support the MME in its selection of the correct target system node to which it should route an Uplink tunnelled message and to provide the target system with information that is needed to resolve technology-specific measurement information (RouteUpdate and pilot strength measurements) that are delivered to the cdma2000 system each eNB cell is associated with a cdma2000 HRPD SectorID and/or with a cdma2000 1xRTT SectorID (generically referred to as cdma2000 reference cellid). This cdma2000 reference cellid is provided by the eNB to the MME using the cdma2000 message transfer capability over S1-AP and forwarded to the target system via the S101 interface and corresponding interface to the cdma2000 1xRTT system. Tunnelling is achieved over the E-UTRAN radio interface by encapsulating tunnelled cdma2000 messages in the UL Information Transfer (for pre-registration signalling) or UL Handover Preparation transfer (for handover signalling) and DL Information Transfer RRC messages (e.g., similar to UMTS Uplink/Downlink Direct Transfer). The reason for using different UL transfer messages is so that the UL Handover Preparation transfer messages can use a higher priority signalling radio bearer. For the UL/DL Information Transfer messages a specific IE in these RRC messages is used to identify the type of information contained in the message (e.g., NAS, TunneledMsg). Additionally if the message is carrying a tunnelled message, an additional IE is included to carry cdma2000 specific RRC Tunnelling Procedure Information (e.g. RAT type). AS level security will be applied for these UL Information Transfer / UL Handover Preparation Transfer and DL Information Transfer RRC messages as normal but there is no NAS level security for these tunnelled cdma2000 messages.

Figure 10.3.2.1-1: Downlink Direct Transfer

Figure 10.3.2.1-2: Uplink Direct Transfer Tunnelling to the MME is achieved over the S1-MME interface by encapsulating the tunnelled cdma2000 message in a new S1 CDMA tunneling messages. These S1 messages carry in addition to the tunneled message some additional cdma2000 specific IEs (e.g. cdma2000 Reference Cell Id, RAT type, cdma2000 message type).

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10.3.2.2
10.3.2.2.1
10.3.2.2.1.1

Mobility between E-UTRAN and HRPD
Mobility from E-UTRAN to HRPD
HRPD System Information Transmission in E-UTRAN

The HRPD system information block (SIB) shall be sent on the E-UTRAN BCCH. The UE shall monitor the EUTRAN BCCH during the RRC_IDLE and RRC_CONNECTED modes to retrieve the HRPD system information for the preparation of cell reselection or handover from the E-UTRAN to HRPD system. HRPD system information may also be provided to the UE by means of dedicated signalling. The HRPD system information contains HRPD neighbouring cell information, cdma timing information, as well as information controlling the HRPD pre-registration.

10.3.2.2.1.2

Measuring HRPD from E-UTRAN

Measurement events and parameters for HRPD measurements are to be aligned with those defined in section 10.2.3. 10.3.2.2.1.2.1 Idle Mode Measurement Control

UE shall be able to make measurements on the HRPD cells in RRC_IDLE mode to perform cell re-selection. The intra-3GPP inter-RAT idle mode measurement control is re-used to control the idle mode measurements on HRPD. The UE performs measurement on HRPD when the signal quality from E-UTRAN serving cell falls below a given threshold. 10.3.2.2.1.2.2 Active Mode Measurement Control

In RRC_CONNECTED mode, the UE shall perform radio measurements on the HRPD network when directed by the E-UTRAN network. The network provides the required HRPD neighbour cell list information and measurement controls to the UE through dedicated RRC signalling. When needed the eNB is responsible for configuring and activating the HRPD measurements on the UE via the dedicated RRC signalling message. Periodic and event-triggered measurements are supported. For single-radio terminals, measurement gaps are needed to allow the UE to switch into t

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