ETSI TS 143 051 V13.0.0 (2016-01)

ETSI TS 1143 051 V13.0.0 (201616-01)

TECHNICAL SPECIFICATIONION
Digital cellular telecocommunications system (Phahase 2+);
OvOverall description;
Stage 2
(3GPP TS 43.0.051 version 13.0.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS
3GPP TS 43.051 version 13.0.0 Release 13 1 ETSI TS 143 051 V13.0.0 (2016-01)

Reference
RTS/TSGG-0143051vd00
Keywords
GSM
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the
print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
http://portal.etsi.org/tb/status/status.asp
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2016.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 2 ETSI TS 143 051 V13.0.0 (2016-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 3 ETSI TS 143 051 V13.0.0 (2016-01)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 7
1 Scope . 8
2 References . 8
2.1 Normative references . 8
2.2 Informative references . 9
3 Symbols and abbreviations . 10
3.1 Symbols . 10
3.2 Abbreviations . 10
4 GERAN Architecture . 11
4.1 GERAN Reference Architecture . 11
4.2 UMTS Architecture applied to GERAN . 12
4.3 Protocol architecture in PS domain . 13
4.3.1 General . 13
4.3.2 User plane . 14
4.3.3 Control plane . 14
4.4 Protocol architecture in CS domain . 15
4.4.1 General . 15
4.4.2 User plane . 15
4.4.3 Control plane . 15
4.5 Iur-g interface . 16
4.5.1 General principles . 16
4.5.2 Protocol architecture . 17
4.5.3 RNSAP protocol . 17
4.6 Support for MSC/SGSN in pool . 18
4.7 CS services for GERAN Iu-mode . 18
4.8 User Equipment Specific Behaviour Information (UESBI) in GERAN Iu mode . 19
5 Radio Interface Protocol Architecture . 19
5.1 Protocol Structure when connecting through Iu . 19
5.2 Multiplexing Principles . 21
5.2.1 Multiplexing of different types of radio access bearers for one MS . 21
5.2.2 Multiplexing of user plane data from different core network interfaces . 21
5.3 Iu vs A/Gb mode selection . 22
5.3.1 Introduction. 22
5.3.2 PLMN, cell and mode (re-)selection in GERAN . 22
6 User and Control Plane Protocols . 23
6.1 Identifiers in GERAN . 23
6.1.1 IMSI, TMSI and P-TMSI . 23
6.1.2 G-RNTI . 23
6.1.3 NSAPI, RAB ID and RB ID . 23
6.1.4 RB Id, RRB Id, and TFI . 24
6.1.5 USF . 24
6.1.6 SAI . 24
6.1.7 BSC-id . 24
6.1.8 LAI for 3G core network . 24
6.1.9 RAI for the 3G core network . 25
6.1.10 GRA Identity . 25
6.1.11 GERAN internal Cell Identity . 25
6.2 Relay . 25
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 4 ETSI TS 143 051 V13.0.0 (2016-01)
6.3 Radio Resource Control (RRC) . 25
6.3.1 RRC Functions . 25
6.3.2 RRC Connection Levels . 26
6.3.3 RRC Connection Modes . 27
6.3.4 RRC Connection Mobility . 27
6.3.4.1 RRC Connection mobility in RRC-Idle mode . 27
6.3.4.2 RRC Connection mobility in RRC-Connected mode . 27
6.3.5 RRC protocol and messages . 28
6.3.6 Support of Radio Bearers in GERAN . 28
6.4 Packet Data Convergence Protocol (PDCP) . 28
6.4.1 Services provided to upper layers . 28
6.4.2 Services expected from RLC layer . 29
6.4.3 PDCP Functions . 29
6.4.3.1 Transparent Mode . 29
6.4.3.2 Non-Transparent Mode . 29
6.5 Radio Link Control (RLC) . 30
6.5.1 Services provided to upper layer . 30
6.5.2 RLC Functions . 30
6.5.2.1 Transparent Mode . 30
6.5.2.2 Non-Transparent Mode . 30
6.5.2.2.1 Acknowledged Mode . 30
6.5.2.2.2 Unacknowledged Mode . 31
6.6 Medium Access Control (MAC) . 31
6.6.1 Services provided to upper layers . 31
6.6.2 MAC Functions . 31
6.6.2.1 Additional functions for RLC transparent mode . 32
6.6.2.2 Additional functions for RLC non-transparent mode . 32
6.6.3 Model of MAC . 32
6.6.4 MAC operation . 33
6.6.4.1 General . 33
6.6.4.2 TBF establishment . 34
6.6.4.2.0 General . 34
6.6.4.2.1 Uplink resource request from MAC-Idle state . 35
6.6.4.2.1.1 Mobile Originated Transmission . 35
6.6.4.2.1.2 Mobile Terminated Transmission . 35
6.6.4.3 TBF multiplexing and scheduling . 36
6.6.4.3.1 Multiplexing of RLC instances on TBFs . 36
6.6.4.3.2 Scheduling of TBFs on physical-layer resources . 36
6.6.4.4 TBF release . 36
6.6.4.5 TBF reallocation . 37
6.7 RLC/MAC PDU Formats for different protocol modes . 37
6.7.1 Acknowledged RLC mode . 37
6.7.2 Unacknowledged RLC mode . 37
6.7.3 Transparent RLC mode . 37
6.8 Physical Layer (Phy) . 37
6.8.1 Definitions . 37
6.8.2 Services provided to upper layer . 38
6.8.2.1 Specific services of the physical layer in the MS . 38
6.8.3 Logical Channels . 38
6.8.3.1 Traffic channels . 38
6.8.3.2 Control channels . 39
6.8.3.2.1 Broadcast channels . 39
6.8.3.2.2 Common control type channels . 39
6.8.3.2.3 Dedicated control channels . 39
6.8.3.2.4 Cell Broadcast Channel (CBCH) . 39
6.8.4 Basic Physical Subchannels . 39
6.8.4.1 DBPSCH - Dedicated Basic Physical SubCHannel . 40
6.8.4.2 SBPSCH - Shared Basic Physical SubCHannel . 40
6.8.5 Mapping of logical channels onto basic physical subchannels . 40
6.8.5.1 DBPSCH full rate . 40
6.8.5.2 DBPSCH half rate . 40
6.8.5.3 SBPSCH full rate . 41
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 5 ETSI TS 143 051 V13.0.0 (2016-01)
6.8.5.4 SBPSCH half rate . 41
6.8.6 Physical Layer Functions . 42
6.8.7 Channel Coding . 42
6.6.8 Enhanced Power control procedure . 44
6.8.8.1 MS implementation . 45
6.8.8.1.1 MS power control . 45
6.8.8.1.2 MS link quality measurement reports . 45
6.8.8.2 BSS implementation. 45
6.9 Flexible Layer One (FLO) . 45
6.9.1 General . 45
6.9.2 Definitions . 45
6.9.3 Principles . 45
6.9.3.1 General . 45
6.9.3.2 Coding / multiplexing . 46
7 Ciphering . 47
7.1 Location of ciphering in the GERAN protocol architecture . 47
7.2 Inputs to the ciphering algorithm . 47
7.2.1 Ciphering Key . 47
7.2.2 Bearer . 48
7.2.3 Direction . 48
7.2.4 Length . 48
7.2.5 Parameter Settings . 48
8 Integrity protection . 49
8.1 Integrity protection on RRC messages . 49
8.2 Integrity protection on RLC/MAC control messages . 49
8.3 Calculation of message authentication code . 49
9 Mobility Management and Session Management (MM and SM) . 49
10 Sequence Diagrams Examples for Handover . 49
Annex A (informative): Radio Access Bearer Realization . 50
A.1 Conversational Radio Access Bearer . 50
A.2 Streaming, Interactive, Background Radio Access Bearers . 53
A.2.1 Streaming . 53
A.2.2 Interactive . 55
A.2.3 Background . 56
Annex B (informative): RLC/MAC Header format Convention . 57
B.1 GPRS RLC/MAC data block header . 57
B.1.1 Downlink RLC/MAC data block header . 57
B.1.2 Uplink RLC/MAC data block header . 57
B.2 EGPRS RLC/MAC data block header . 57
B.2.1 Downlink RLC/MAC data block header . 57
B.2.2 Uplink RLC/MAC data block header . 58
B.3 ECSD RLC/MAC data block header . 59
B.3.1 Uplink and downlink RLC/MAC data block header . 59
Annex C (informative): RRC States, MAC States and RRC Connection Mobility . 61
C.1 Void . 61
C.2 MAC states . 61
C.2.1 MAC-Dedicated state . 61
C.2.1.1 Transition from MAC-Dedicated state to MAC-Idle state . 61
C.2.1.2 Transition from MAC-Dedicated state to MAC-Shared state . 61
C.2.1.3 Transition from MAC-Dedicated state to MAC-DTM state . 62
C.2.2 MAC-Shared state . 62
C.2.2.1 Transition from MAC-Shared state to MAC-DTM state . 62
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 6 ETSI TS 143 051 V13.0.0 (2016-01)
C.2.2.2 Transition from MAC-Shared state to MAC-Idle state . 62
C.2.2.3 Transition from MAC-Shared state to MAC-Dedicated state . 62
C.2.3 MAC-Idle state . 62
C.2.3.1 Transition from MAC-Idle state to MAC-Dedicated state. 62
C.2.3.2 Transition from MAC-IDLE state to MAC-SHARED state . 62
C.2.4 MAC-DTM state . 62
C.2.4.1 Transition from MAC-DTM state to MAC-Dedicated state . 62
C.2.4.2 Transition from MAC-DTM state to MAC-Shared state . 62
C.3 Mapping between RRC States and MAC States . 63
Annex D (informative): Change history . 64
History . 66

ETSI
3GPP TS 43.051 version 13.0.0 Release 13 7 ETSI TS 143 051 V13.0.0 (2016-01)
Foreword
rd
This Technical Specification has been produced by the 3 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.
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 8 ETSI TS 143 051 V13.0.0 (2016-01)
1 Scope
The present document defines the stage 2 service description for a GSM/EDGE Radio Access Network (GERAN).
ITU-T Recommendation I.130 describes a three-stage method for characterisation of telecommunication services, and
CCITT Q.65 defines stage 2 of the method.
The present document illustrates how the services requested by a GSM/UMTS Core Network are realized by the
GERAN.
The main focus of the present document is on functionality related to the Iu interfaces. The aim of the present document
is not to describe functionality related to the A and Gb interfaces in details. There is no detailed description of the
interfaces towards the core network and only references are given to the appropriate specifications.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• 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.
2.1 Normative references
[1] 3GPP TS 25.410: "UTRAN Iu Interface: General Aspects and Principles".
[2] 3GPP TS 25.411: "UTRAN Iu interface Layer 1".
[3] 3GPP TS 25.412: "UTRAN Iu interface signalling transport".
[4] 3GPP TS 25.413: "UTRAN Iu interface RANAP signalling".
[5] 3GPP TS 25.414: "UTRAN Iu interface data transport & transport signalling".
[6] 3GPP TS 25.415: "UTRAN Iu interface user plane protocols".
[7] 3GPP TS 48.014: "General Packet Radio Service (GPRS); Base Station System (BSS) - Serving
GPRS Support Node (SGSN) interface; Gb interface Layer 1".
[8] 3GPP TS 48.016: "General Packet Radio Service (GPRS); Base Station System (BSS) - Serving
GPRS Support Node (SGSN) interface; Network Service".
[9] 3GPP TS 48.018: "General Packet Radio Service (GPRS); Base Station System (BSS) - Serving
GPRS Support Node (SGSN); BSS GPRS Protocol (BSSGP)".
[10] 3GPP TS 45.001: "Digital cellular telecommunications system (Phase 2+); Physical layer on the
radio path; General description".
[11] 3GPP TS 45.002: "Digital cellular telecommunications system (Phase 2+); Multiplexing and
multiple access on the radio path".
[12] 3GPP TS 43.002: "Network Architecture".
[13] 3GPP TS 48.001: "Base Station System - Mobile Services Switching Centre (BSS-MSC) Interface
General Aspects".
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 9 ETSI TS 143 051 V13.0.0 (2016-01)
[14] 3GPP TS 48.002: "Base Station System - Mobile Services Switching Centre (BSS-MSC) Interface
- Interface Principles".
[15] 3GPP TS 48.004: "Base Station System - Mobile Services Switching Centre (BSS-MSC) Interface
Layer 1 Specification".
[16] 3GPP TS 48.006: "Signalling Transport Mechanism Specification for the Base Station System -
Mobile Services Switching Centre (BSS-MSC) Interface".
[17] 3GPP TS 48.008: "Mobile Switching Centre - Base Station system (MSC-BSS) Interface Layer 3
Specification".
[18] 3GPP TS 48.063: "Inband Tandem Free Operation (TFO) of Speech Codecs; Service Description;
Stage 3".
[19] 3GPP TS 25.420: "UTRAN Iur Interface: General Aspects and principles".
[20] 3GPP TS 25.421: "UTRAN Iur Interface Layer 1".
[21] 3GPP TS 25.422: "UTRAN Iur Interface signalling transport".
[22] 3GPP TS 25.423: "UTRAN Iur Interface RNSAP signalling".
[23] 3GPP TS 24.022: "Radio Link Protocol (RLP) for Circuit Switched Bearer and Teleservices".
[24] 3GPP TS 44.018: "Radio Resource Control Protocol".
[25] 3GPP TS 24.008: 'Mobile radio interface layer 3 specification; Core Network Protocols - Stage 3'.
[26] 3GPP TS 44.060: 'Radio Link Control / Medium Access Control (RLC/MAC) protocol'.
[27] 3GPP TS 45.008: 'Radio subsystem Link Control'.
[28] 3GPP TS 23.003: "Numbering, Addressing and Identification".
[29] 3GPP TS 23.221: 'Architectural requirements (Release 5)'
[30] 3GPP TS 23.236: 'Intra Domain Connection of RAN Nodes to Multiple CN Nodes'
[31] 3GPP TS 23.195: 'Provision of User Equipment Specific Behaviour Information (UESBI) to
network entities'
2.2 Informative references
[32] 3GPP TS 23.060: "General Packet Radio Service (GPRS); Service Description; Stage 2".
[33] 3GPP TS 43.64: "General Packet Radio Service (GPRS); Overall description of the GPRS radio
interface; Stage 2".
[34] 3GPP TS 23.034: "High Speed Circuit Switched Data (HSCSD); Stage 2".
[35] 3GPP TS 41.004: "Digital cellular telecommunications system (Phase 2+); Abbreviations and
acronyms".
[36] ITU-T Recommendation I.130: "Method for the characterization of telecommunication services
supported by an ISDN and network capabilities of an ISDN".
[37] ITU-T Recommendation Q.65: "The unified functional methodology for the characterization of
services and network capabilities including alternative object-oriented techniques".
[38] 3GPP TS 23.153: 'Out of Band Transcoder Control'
[39] 3GPP TR 45.902: 'Flexible Layer One'
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 10 ETSI TS 143 051 V13.0.0 (2016-01)
3 Symbols and abbreviations
3.1 Symbols
For the purposes of the present document, the following symbols apply:
A Interface between a BSS and a 2G MSC
Gb Interface between a BSS and a 2G SGSN
Iu-cs Interface between a BSS and a 3G MSC
Iu-ps Interface between a BSS and a 3G SGSN
Iur-g Interface between two BSSs
NOTE: whether the Iur-g interface is also used between a BSS and an RNC is FFS.
Um Interface between MS and BSS
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply. Additional applicable abbreviations can be
found in 3GPP TS 41.004 [27]and 3GPP TS 43.064 [25].
ADCH Associated Dedicated CHannel
ARQ Automatic Repeat reQuest
AS Access Stratum
BCCH Broadcast Control CHannel
BSS Base Station Subsystem
CBCH Cell Broadcast CHannel
CC Call Control
CDCH Control-plane DCH
CN Core Network
CPBCCH COMPACT PBCCH
CS-i GPRS Coding Scheme i
DC Dedicated Control
DCH Dedicated CHannel
DLC Data Link Control
DBPSCH Dedicated Basic Physical Sub CHannel
ECSD Enhanced Circuit Switched Data
EDGE Enhanced Data rates for Global Evolution
E-FACCH Enhanced FACCH
E-IACCH Enhanced Inband Associated Control CHannel
EGPRS Enhanced GPRS
EPC Enhanced Power Control
EPCCH Enhanced Power Control CHannel
E-TCH Enhanced TCH
FACCH Fast Associated Control CHannel
FLO Flexible Layer One
FPC Fast Power Control
GC General Control
GERAN GSM/EDGE Radio Access Network
GPRS General Packet Radio Service
GRA GERAN Registration Area
G-RNTI GERAN Radio Network Temporary Identity
GSM Global System for Mobile Communications
IETF Internet Engineering Task Force
IMSI International Mobile Subscriber Identity
IP Internet Protocol
LCS LoCation Services
MAC Medium Access Control
MCS-i EGPRS Modulation and Coding Scheme i
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 11 ETSI TS 143 051 V13.0.0 (2016-01)
MM Mobility Management
MS Mobile Station
NAS Non Access Stratum
NSAPI Network layer SAPI
Nt Notification
O-FACCH Octal FACCH
O-TCH Octal TCH
PBCCH Packet BCCH
PDCH Packet Data CHannel
PDCP Packet Data Convergence Protocol
PDP Packet Data Protocol
PDTCH Packet Data TCH
PDU Packet Data Unit
PLMN Public Land Mobile Network
PTCCH Packet Timing advance Control CHannel
P-TMSI Packet TMSI
PUESBINE Provision of UE Specific Behaviour Information to Network Entities
QoS Quality of Service
RAB Radio Access Bearer
RANAP Radio Access Network Application Part
RB Radio Bearer
RLC Radio Link Control
RNSAP Radio Network Subsystem Application Part
ROHC Robust Header Compression
RRC Radio Resource Control
RTP Real Time Protocol
SACCH Slow Associated Control CHannel
SACCH/TP SACCH for enhanced power control
SAP Service Access Point
SAPI Service Access Point Identifier
SDCCH Stand-alone Dedicated Control CHannel
SDU Service Data Unit
SBPSCH Shared Basic Physical Sub CHannel
TB Transport Block
TBF Temporary Block Flow
TCH Traffic Channel
TCP Transmission Control Protocol
TFC Transport Format Combination
TFCI Transport Format Combination Indicator
TFCS Transport Format Combination Set
TLLI Temporary Logical Link Identifier
TMSI Temporary Mobile Subscriber Identity
TrCH Transport Channel
TTI Transmission Time Interval
UDCH User-plane DCH
UDP User Datagram Protocol
UESBI UE Specific Behaviour Information
UMTS Universal Mobile Telecommunication System
USF Uplink State Flag
UTRAN UMTS Terrestrial Radio Access Network
4 GERAN Architecture
4.1 GERAN Reference Architecture
The reference architecture of GERAN is illustrated in Figure 1.
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 12 ETSI TS 143 051 V13.0.0 (2016-01)
GERAN connects with 3 interfaces A, Gb and Iu interfaces to the core network. Any combination comprising one, two
or three of these 3 interfaces is possible. Two Base Station Subsystems (BSS) may be connected to each other with an
Iur-g interface. A BSS and an RNC may also be connected via an Iur-g interface.
The mobile station shall operate using only the following modes:
a) A/Gb mode, e.g. for pre-Release 5 terminals, for Release 5 terminals when connected to a GERAN with no I
u
interface towards the Core Network;
b) Iu mode (i.e. I and I ), e.g. for Release 5 terminals when connected to a GERAN with I interfaces towards
u-CS u-PS u
the Core Network.
Both modes must be supported by the standard and no other modes (e.g. A / I or I / G ) shall be allowed.
u-PS u-CS b
GERAN
BSS
Iur-g
Um
A
MS
BTS
Gb
MS BSC
BTS
Iu
BSS
Iur-g
UTRAN
GSM/UMTS
RNC
Core Network
Figure 1: GERAN reference architecture
The functional split within a BSS is implementation-dependent.
4.2 UMTS Architecture applied to GERAN
This clause describes the GERAN architecture when it connects to the core network through an Iu interface. Figure 2
shows the assumed UMTS architecture as outlined in 3GPP TS 23.110. GERAN is showed instead of UTRAN. The
figure below shows the UMTS architecture in terms of its entities Mobile Station, GERAN and Core Network. The
respective reference points Um (Radio Interface) and Iu (CN-RAN reference) are shown. The figure illustrates
furthermore the high-level functional grouping into the Access Stratum and the Non-Access Stratum.
The Access Stratum offers services through the following Service Access Points (SAP) to the Non-Access Stratum:
- General Control (GC) SAPs;
- Notification (Nt) SAPs; and
- Dedicated Control (DC) SAPs.
The SAPs are marked with circles in Figure 2.
ETSI
3GPP TS 43.051 version 13.0.0 Release 13 13 ETSI TS 143 051 V13.0.0 (2016-01)
Non-Access Stratum
Nt
GC
DC DC
GC Nt
Access Stratum
GERAN
Core Network
MS
Radio
Iu
(Um)
Figure 2: UMTS Architecture applied to GERAN
This model can be further refined to distinguish the end AS entities, which provide the services to higher layers, from
the local entities, which provide services over respectively the Um and the Iu reference point. Figure 3 presents the
refined model.
Nt
DC GC
GC Nt DC
Relay
DC
GC Nt
DC
DC
GC Nt GC Nt DC
GC Nt
Um Stratum Iu Stratum
GERAN
MS Core Network
Radio
Iu
(Um)
Figure 3: Assumed GERAN Model
4.3 Proto
...