ETSI TS 102 744-1-2 V1.1.1 (2015-10)

Satellite Earth Stations and Systems (SES); Family SL Satellite Radio Interface (Release 1); Part 1: General Specifications; Sub-part 2: System Operation Overview

DTS/SES-00299-1-2

General Information

• Status: Published
• Publication Date: 25-Oct-2015
• Technical Committee: SES SCN - Satellite Communications and Navigation
• Current Stage: 12 - Completion
• Due Date: 25-Sep-2015
• Completion Date: 26-Oct-2015

Standards Content (Sample)

TECHNICAL SPECIFICATION
Satellite Earth Stations and Systems (SES);
Family SL Satellite Radio Interface (Release 1);
Part 1: General Specifications;
Sub-part 2: System Operation Overview

2 ETSI TS 102 744-1-2 V1.1.1 (2015-10)

Reference
DTS/SES-00299-1-2
Keywords
3GPP, GPRS, GSM, GSO, interface, MSS, radio,
satellite, TDM, TDMA, UMTS
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

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 2015.
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
3 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
Contents
Intellectual Property Rights . 6
Foreword . 6
Modal verbs terminology . 6
Introduction . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 7
3 Abbreviations . 8
4 Stratum introduction . 9
5 Mobility Management (MM) . 9
5.1 General principles. 9
5.2 RRC States (Idle and Connected Mode). 10
5.3 UE and Network Operation Modes . 11
5.4 Mobility Management Service States . 12
5.4.0 General . 12
5.4.1 PS Domain Service State Machine . 12
5.4.1.0 General . 12
5.4.1.1 PMM-DETACHED State . 12
5.4.1.2 PMM-IDLE State . 12
5.4.1.3 PMM-CONNECTED State . 13
5.4.1.4 State Transitions and Functions . 13
5.4.1.5 Periodic Routing Area Update Timer . 14
5.4.1.6 Mobile Reachable Timer . 14
5.4.2 CS Domain Service State Machine . 14
5.4.2.0 General . 14
5.4.2.1 CMM-DETACHED State . 14
5.4.2.2 CMM-IDLE State . 15
5.4.2.3 CMM-CONNECTED State . 15
5.5 Connection Maintenance . 15
5.6 Mobility Management Procedures . 16
6 Numbering, Addressing and Identification . 16
6.0 General . 16
6.1 Non-Access Stratum . 16
6.1.0 General . 16
6.1.1 PLMN Identifier (PLMN ID). 16
6.1.2 International Mobile Subscriber Identity (IMSI) . 16
6.1.3 Temporary Mobile Subscriber Identity (TMSI) and Packet Temporary Mobile Subscriber Identity
(P-TMSI) . 16
6.1.4 International Mobile Station Equipment Identity/Software Version (IMEI/IMEISV) . 16
6.1.5 Location Area Identification (LAI) . 17
6.1.6 Routing Area Identification (RAI) . 17
6.1.7 Mobile Station International PSTN/ISDN Number (MSISDN) . 18
6.1.8 Mobile Station Roaming Number (MSRN) . 18
6.1.9 Mobile Station International Data Number . 18
6.1.10 IPv4 Address . 18
6.1.11 IPv6 Address . 18
6.1.12 Access Point Name . 18
6.2 Access Stratum (Usl Stratum) . 18
6.2.1 UE Identification . 18
6.2.1.0 General . 18
6.2.1.1 RRC-IDLE Mode . 18
6.2.1.2 RRC-CONNECTED Mode . 18
ETSI
4 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
6.2.2 Radio Resource to Network Layer UE Identity Association . 19
6.2.3 Logical Radio Interface Connection Identifiers . 19
6.2.4 Other Identifiers . 19
6.2.4.1 Spot Beam ID . 19
6.3 Access Stratum (Iu Stratum) . 19
6.3.0 General . 19
6.3.1 PLMN Identifier (PLMN ID). 19
6.3.2 CN Domain Identifier . 19
6.3.3 CN Domain Indicator. 19
6.3.4 RNC Identifier . 20
6.3.5 RNC Addresses . 20
6.3.6 Service Area Identifier (SAI) . 20
6.3.7 Permanent NAS UE Identity . 21
6.3.8 Temporary NAS UE Identity . 21
6.3.9 Radio Access Bearer Identity (RAB ID). 21
6.3.10 Iu Signalling Connection Identifier . 22
6.3.11 Paging Area Identity . 22
7 System Information . 22
7.1 General Principles . 22
7.2 System Information in Idle and Connected Modes . 22
7.3 System Information Elements . 23
7.3.0 General . 23
7.3.1 Access Stratum System Information . 23
7.3.1.0 General . 23
7.3.1.1 Primary Bearer . 23
7.3.1.2 PLMN ID . 24
7.3.1.3 Access Control . 24
7.3.1.4 Spot Beam Map . 24
7.3.1.5 Common Signalling Retry . 24
7.3.1.6 GPS Policy Info . 24
7.3.2 Non-Access Stratum System Information . 24
8 UE Idle Mode Behaviour . 25
8.1 NAS/AS Functional Divisions . 25
8.2 Idle Mode Procedures . 25
8.2.1 Non-Access Stratum . 25
8.2.2 Access Stratum (Usl Stratum) . 25
8.2.2.0 General . 25
8.2.2.1 PLMN Discovery . 26
8.2.2.2 PSAB Discovery . 26
8.2.2.2.1 Method. 26
8.2.2.2.2 Spot Beam Selection Methods . 26
9 Sleep Mode . 26
Annex A (informative): System operation . 28
A.1 Introduction . 28
A.1.1 Network Architecture . 28
A.1.2 Adaptation Layer . 28
A.2 Example Call Flows . 28
A.2.1 User Equipment Start up Sequence . 28
A.2.2 Selection of Primary Shared Access Bearer . 29
A.2.2.0 General . 29
A.2.2.1 Spot Beam Hierarchy . 29
A.2.2.2 Regional Beam Selection . 30
A.2.2.3 Narrow Beam Access. 30
A.2.3 PSAB Selection Process . 30
A.2.4 Registration on the Satellite Network . 31
A.2.5 Attach Procedure and Combined Procedures . 32
A.2.5.0 General . 32
A.2.5.1 IMSI Attach Procedure . 33
ETSI
5 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
A.2.5.2 GPRS Attach Procedure . 35
A.2.6 Mobile Originated Circuit Switched Call Set Up . 36
A.2.7 Emergency Calls . 37
A.2.8 Mobile Terminated Circuit Switched Call Set Up . 40
A.2.9 Circuit Switched Call Clearing . 42
A.2.10 Activation of Packet Switched Session, "PDP Context" . 43
A.2.11 Deactivation of Packet Switched Session . 45
A.2.12 Preservation of PDP context during release of RAB/PS signalling connection . 46
A.2.12.0 General . 46
A.2.12.1 Temporary Release of a Packet Switched Radio Access Bearer due to Inactivity. 46
A.2.12.1.0 General . 46
A.2.12.1.1 Uplink PDU causing restoration of packet switched RAB following Earlier release . 46
A.2.12.1.2 Downlink PDU causing restoration of Packet Switched RAB following earlier RAB release . 47
A.2.12.2 Temporary Release of a Packet Switched Signalling Connection due to Inactivity . 48
A.2.12.2.0 General . 48
A.2.12.2.1 Uplink PDU arrival causing restoration of PS Signalling connection and RABs following Earlier
release . 48
A.2.12.2.2 Downlink PDU arrival causing restoration of Iu PS Signalling connection and RABs following
Earlier release . 50
A.2.13 PS and CS detach . 52
A.2.13.1 CS Detach, Mobile Originated . 52
A.2.13.2 Mobile Initiated Detach via the PS Domain (GPRS Detach, IMSI Detach or combined GPRS/IMSI
Detach) . 52
A.2.14 Handover . 54
A.2.14.0 General . 54
A.2.14.1 Radio Access Bearer Set-up and Release . 54
A.2.14.2 Change in UE Location . 55
A.2.15 Deregistration . 55
A.2.16 MBMS Context Activation . 56
A.2.17 MBMS Context Deactivation . 56
History . 57

ETSI
6 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
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 (http://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 Technical Committee Satellite Earth Stations and
Systems (SES).
The present document is part 1, sub-part 2 of a multi-part deliverable. Full details of the entire series can be found in
ETSI TS 102 744-1-1 [i.11].
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.
Introduction
This multi-part deliverable (Release 1) defines a satellite radio interface that provides UMTS services to users of mobile
terminals via geostationary (GEO) satellites in the frequency range 1 518,000 MHz to 1 559,000 MHz (downlink) and
1 626,500 MHz to 1 660,500 MHz and 1 668,000 MHz to 1 675,000 MHz (uplink).
ETSI
7 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
1 Scope
The present document provides an overview of the Family SL system operation, and describes fundamental UMTS
elements such as mobility management, numbering and addressing, and idle mode behaviour as they apply to the
Family SL satellite network. In general, these elements are the same for both terrestrial UMTS and the satellite network.
Where appropriate, references to 3GPP documents are given, otherwise the text highlights the areas where the terrestrial
UMTS and Family SL elements differ.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
[1] ETSI TS 123 003: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Numbering, addressing and identification
(3GPP TS 23.003 Release 4)".
[2] ETSI TS 123 060: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); General Packet Radio Service (GPRS); Service
description; Stage 2 (3GPP TS 23.060 Release 4)".
[3] ETSI TS 123 122: "Universal Mobile Telecommunications System (UMTS); Non-Access-Stratum
functions related to Mobile Station (MS) in idle mode (3GPP TS 23.122 Release 4)".
[4] ETSI TS 125 413: "Universal Mobile Telecommunications System (UMTS); UTRAN Iu interface
Radio Access Network Application Part (RANAP) signalling (3GPP TS 25.413 Release 4)".
[5] ETSI TS 102 744-1-4: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 1: General Specifications; Sub-part 4: Applicable External
Specifications, Symbols and Abbreviations".
[6] Recommendation ITU-T E.164: "The international public telecommunication numbering plan".
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TS 122 101: "Universal Mobile Telecommunications System (UMTS); Service aspects;
Service principles (3GPP TS 22.101 Release 4)".
[i.2] ETSI TS 123 221: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Architectural requirements (3GPP TS 23.221 Release 4)".
ETSI
8 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
[i.3] ETSI TS 124 007: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Mobile radio interface signalling layer 3; General Aspects
(3GPP TS 24.007 Release 4)".
[i.4] ETSI TS 124 008: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Mobile radio interface Layer 3 specification; Core network
protocols; Stage 3 (3GPP TS 24.008 Release 4)".
[i.5] ETSI TS 125 331: "Universal Mobile Telecommunications System (UMTS); Radio Resource
Control (RRC) protocol specification (3GPP TS 25.331 Release 4)".
[i.6] ETSI TS 133 102: "Universal Mobile Telecommunications System (UMTS); 3G security; Security
architecture (3GPP TS 33.102 Release 4)".
[i.7] Recommendation ITU-T E.212: "The international identification plan for public networks and
subscriptions".
[i.8] ETSI TS 122 060: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); General Packet Radio Service (GPRS); Service
description; Stage 1 (3GPP TS 22.060 Release 4)".
[i.9] ETSI TS 122 011: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); Service accessibility (3GPP TS 22.011 Release 4)".
[i.10] ETSI TS 125 304: "Universal Mobile Telecommunications System (UMTS); User Equipment
(UE) procedures in idle mode and procedures for cell reselection in connected mode
(3GPP TS 25.304 Release 4)".
[i.11] ETSI TS 102 744-1-1: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 1: General Specifications; Sub-part 1: Services and Architectures".
[i.12] ETSI TS 102 744-3-1: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 1: Bearer
Control Layer Interface".
[i.13] ETSI TS 102 744-3-2: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 2: Bearer
Control Layer Operation".
[i.14] ETSI TS 102 744-3-5: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 5: Adaptation
Layer Interface".
[i.15] ETSI TS 102 744-3-6: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 6: Adaptation
Layer Operation".
[i.16] ETSI TS 102 744-3-7: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 7: NAS Layer
Interface Extensions for MBMS Services".
[i.17] ETSI TS 102 744-3-8: "Satellite Earth Stations and Systems (SES); Family SL Satellite Radio
Interface (Release 1); Part 3: Control Plane and User Plane Specifications; Sub-part 8: NAS Layer
and User Plane Operation for MBMS Services".
[i.18] Recommendation ITU-T E.213: "Telephone and ISDN numbering plan for land mobile stations in
public land mobile networks (PLMN)".
3 Abbreviations
For the purposes of the present document, the abbreviations given in ETSI TS 102 744-1-4 [5], clause 3 apply.
ETSI
9 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
4 Stratum introduction
For reference purposes, the functional aspects of the Family SL satellite network are shown in Figure 4.1. The
Non-Access Stratum (NAS) groups together all protocols between the UE and the CN. The Access Stratum is divided
into an Usl Stratum, which groups all protocols between the UE and RNS and an Iu Stratum, which groups all protocols
between the RNS and CN. By definition the Usl and Iu Strata cross the Usl and Iu interfaces respectively.
U I
SL U
CMCM CMCM
MMMM MMMM
Non-Access Stratum
RELAY
ALAL ALAL RARANAPNAP RARANAPNAP
BCnBCn BCBCnn
SCSCCPCP SCCSCCPP
BCBCtt BCtBCt ovoverer ovoverer
ATATMM ATATMM
L1L1 L1L1
U Stratum I Stratum
SL U
Access Stratum
UE RNS CN
Figure 4.1: Stratum Divisions
5 Mobility Management (MM)
5.1 General principles
UMTS Layer 3 in the Control Plane contains two primary sublayers: Mobility Management (MM) and Connection
Management (CM); see ETSI TS 124 007 [i.3], Figure 5.6. The CM sublayer controls access to circuit switched, packet
switched, messaging, and other supplementary services. The MM sublayer is primarily responsible for tracking the
location of the mobile subscribers within the satellite network and authorizing access to the network. MM provides
services to entities in the CM sublayer (i.e. CM messages are transported by MM).
The MM sublayer contains two protocol entities: GPRS Mobility Management (GMM) for the PS domain and Mobility
Management (MM) for the CS domain. There is one instance of GMM and one instance of MM in both the UE and the
network (SGSN and MSC respectively).
As shown in Figure 5.1, the MM sublayer is entirely contained within the Non-Access Stratum. GMM and MM
procedures and the contents of messages (PDUs) are fully transparent to the Access Stratum. Since the CM sublayer
uses services from the MM sublayer, Call Control (CC), Session Management (SM), GPRS Short Message Service
(GSMS) and Supplementary Service (SS) messages and procedures are also transparent to the Access Stratum.
ETSI
10 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
U I
SL U
SMSMSM CCCCCC SSSSSS SMSSMSSMS SMSMSM CCCCCC SSSSSS SMSSMSSMS
UMTS LAYER 3 – CONNECTION MANAGEMENT SUBLAYER (CM)
GMGMMM MMMM GMGMMM MMMM
UMTS LAYER 3 – MOBILITY MANAGEMENT SUBLAYER (MM)
Non-Access Stratum
U Stratum I Stratum
SL U
Access Stratum
UE RNS CN
Figure 5.1: UMTS Layer 3 in Non-Access Stratum
5.2 RRC States (Idle and Connected Mode)
In terrestrial UMTS, the terms "idle mode" and "connected mode" refers to states of the Radio Resource Control (RRC)
protocol layer (see ETSI TS 125 331 [i.5]). The RRC protocol [i.5] is not directly implemented in the satellite network;
however, the Adaptation Layer (specifically the REGM entity, see ETSI TS 102 744-3-5 [i.14]) is responsible for
maintaining the equivalent RRC state machine.
In the satellite network context, the RRC state (or mode) refers to the presence or absence of a UE-Specific Signalling
connection between the UE and the RNC. This connection is established at the (successful) conclusion of the
Registration procedure and released at the conclusion of the Deregistration procedure.
There are two main RRC states illustrated in Figure 5.2 and defined as follows:
• RRC-IDLE: no UE-Specific Signalling connection is established between UE and RNC.
• RRC-CONNECTED: a UE-Specific Signalling connection is established between the UE and the RNC which
is serving the UE (the "Serving RNC" or SRNC).
ETSI
11 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
RRC-IDLE
(REGM-IDLE)
UE-Specific
UE-Specific
Signalling Connection
Signalling Connection
Release
Establish
(Deregistration)
(Registration)
RRC-CONNECTED
(REGM-REGISTERED)
Figure 5.2: Equivalent RRC States in the satellite network
5.3 UE and Network Operation Modes
A UE can operate in one of three modes:
• PS/CS Mode: The UE is attached to both the PS domain and CS domain, and the UE is capable of
simultaneously operating PS services and CS services. This mode of operation is equivalent to the GSM GPRS
Class-A mode of operation.
• PS mode: The UE is attached to the PS domain only and may only operate services of the PS domain.
However, this does not prevent CS-like services to be offered over the PS domain. This mode of operation is
equivalent to the GSM GPRS Class-C mode of operation.
• CS mode: The UE is attached to the CS domain only and may only operate services of the CS domain.
However, this does not prevent PS-like service to be offered over the CS domain.
The satellite network may operate either in Mode I or Mode II, i.e. the Gs interface between the MSC/VLR and SGSN
may or may not exist for the purpose of coordinating GMM and MM functions (i.e. Attach, Location/Routing Area
Update, Paging, etc.). The network mode of operation (NMO) is indicated to the UE as part of the broadcast system
information.
Based on the mode of operation indicated by the network, the UE can then choose whether it can attach to CS domain
services, to PS domain services, or to both, according to its mode of operation [i.8]. Furthermore, based on the mode of
operation, the UE can choose whether it can initiate combined update procedures or separate update procedures,
according to its capabilities. The combined GMM/MM functions avoid the need to send both MM and GMM messages
when the PS domain can pass the necessary information to the CS domain privately within the CN.
A UE operating in CS/PS mode may have two signalling connections to the CN: a CS signalling connection to the
MSC/VLR and a PS signalling connection to the SGSN. Signalling connections have two components: an Iu connection
(RNC to CN) and an UE-Specific Signalling Connection (UE to RNC). Even though two separate Iu connections are
required for the CS and PS domains (i.e. Iu-CS and Iu-PS), a single UE-Specific Signalling Connection is used for both
the PS and CS domain (see Figure 5.3). The Adaptation Layer is responsible for the routing of signalling to and from
the correct domain.
ETSI
12 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
CS Service
PS Service
Domain
Domain
CS State PS State
MSC/VLR SGSN
2 x
Iu Signalling
Connections/
RANAP
Instances
RAN
1 x
UE=Specific
Signalling
Connecton
UE
CS State
PS State
Figure 5.3: Relationship Between Service States and Signalling Connections
5.4 Mobility Management Service States
5.4.0 General
Each domain has its own service state machine (see Figure 5.3). An UE, that is supporting both CS services and PS
services, has a CS service state machine and a PS service state machine. For every UE, there is a corresponding PS state
machine and CS state machine in the SGSN and MSC respectively. The two peers of the service state machine are
working independently to each other, although associated to the same UE. The UE-CN signalling aims to keep the peer
entities synchronized.
5.4.1 PS Domain Service State Machine
5.4.1.0 General
The PS service state machine is called Packet Mobility Management (or PMM).
5.4.1.1 PMM-DETACHED State
In the PMM-DETACHED state there is no communication between the UE and the SGSN. The UE and SGSN PMM
contexts hold no valid location or routing information for the UE. The UE MM state machine does not react on system
information related to the SGSN. The UE is not reachable by a SGSN, as the UE location is not known.
In order to establish PMM contexts in the UE and the SGSN, the UE shall perform the (GMM) GPRS Attach procedure.
When the PS signalling connection is established between the UE and the SGSN for performing the (GMM) GPRS
Attach procedure, the state changes to PMM-CONNECTED in the SGSN and in the UE. A complete PS signalling
connection is made up of two parts: an Iu connection (RNC to SGSN) and an UE-Specific Signalling Connection (UE
to RNC).
5.4.1.2 PMM-IDLE State
In the PMM-IDLE state, a complete PS signalling connection is not established between the UE and SGSN, but the UE
and SGSN have (previously) established PMM contexts. The UE location is known in the SGSN with an accuracy of a
routing area. Paging is needed in order to reach the UE, e.g. for signalling. The UE shall perform the (GMM) Routing
Area Update (RAU) procedure if the RA changes. Signalling towards the HLR is needed if the SGSN does not have a
PMM context for this UE.
ETSI
13 ETSI TS 102 744-1-2 V1.1.1 (2015-10)
The UE and SGSN shall enter the PMM-CONNECTED state whenever the complete PS signalling connection is
re-established between the UE and SGSN (required to initiate any GMM procedure).
While in the PMM-IDLE state, the SGSN or the UE may perform an implicit detach (i.e. without signalling), after
which the local PMM state only changes to PMM-DETACHED. The SGSN may perform an implicit GPRS Detach any
time after the UE Mobile Reachable Timer expires. The UE's PMM context in the SGSN is deleted, preferably after a
certain (implementation dependent) time. The HLR may be informed about the deletion. The UE may perform an
implicit GPRS Detach when, for example, the battery or USIM are removed, or the UE is switched off.
5.4.1.3 PMM-CONNECTED State
The UE location is known in the SGSN with an accuracy of a serving RNC. In the PMM-CONNECTED state, the
location of the UE is tracked by the serving RNC. The UE performs the (GMM) Routing Area Update procedure if the
RA changes (or if the RAI in the System Information broadcast changes).
When an UE and a SGSN are in the PMM-CONNECTED state, a complete PS signalling connection is established
between the UE and the SGSN and GMM procedures can be initiated. In the SGSN, PS signalling connection release or
changes the state to PMM-IDLE.
The UE shall enter the PMM-IDLE state when its PS signalling connection to the SGSN has been released or broken
(i.e. the Iu-PS connection and/or the UE-Specific Signalling connection is released or broken). The signalling
connection release is explicitly indicated by the RNC to the UE or detected by the UE.
After a signalling procedure (e.g. Routing Area Update), the SGSN may decide to release the PS signalling connection,
after which the state is changed to PMM-IDLE. Completion of the (GMM) GPRS Detach procedure (either initiated by
the UE or the SGSN) changes the state to PMM-DETACHED.
5.4.1.4 State Transitions and Functions
Figure 5.4 shows the PMM state machine in both the UE and SGSN. Note that the PMM-IDLE and PMM-
CONNECTED states are independent of the Session Management state. The activation or deactivation of PDP Contexts
by the SM entity does not affect the PMM state.
START
PMM-DETACHED
GMM: GPRS Attach
Implicit
Detach
GMM: GPRS Detach
PS Signalling
Connection Release
PMM-IDLE PMM-CONNECTED
(SM-ACTIVE or (SM-ACTIVE or
SM-INACTIVE) SM-INACTIVE)
PS Signalling
Connection Establish
Note: This
transition in SGSN
State Machine Only
Serving RNC
Relocation
Figure 5.4: PS Domain Service State Machine in UE and
...