ETSI TS 144 068 V14.0.0 (2017-04)

Digital cellular telecommunications system (Phase 2+) (GSM); Group Call Control (GCC) protocol (3GPP TS 44.068 version 14.0.0 Release 14)

RTS/TSGC-0144068ve00

General Information

• Status: Published
• Publication Date: 09-Apr-2017
• Technical Committee: 3GPP CT 1 - MM/CC/SM [lu] (formely CN1)
• Current Stage: 12 - Completion
• Completion Date: 10-Apr-2017

Standards Content (Sample)

ETSI TS 144 068 V14.0.0 (2017-04)






TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Group Call Control (GCC) protocol
(3GPP TS 44.068 version 14.0.0 Release 14)

R
GLOBAL SYSTEM FOR
MOBILE COMMUNICATIONS

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3GPP TS 44.068 version 14.0.0 Release 14 1 ETSI TS 144 068 V14.0.0 (2017-04)



Reference
RTS/TSGC-0144068ve00
Keywords
GSM
ETSI
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ETSI

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3GPP TS 44.068 version 14.0.0 Release 14 2 ETSI TS 144 068 V14.0.0 (2017-04)
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

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3GPP TS 44.068 version 14.0.0 Release 14 3 ETSI TS 144 068 V14.0.0 (2017-04)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 Applicability . 7
5 Main concepts . 7
6 Elementary procedures for Group Call Control . 8
6.1 Overview . 8
6.1.1 General . 8
6.1.2 Group call control states . 10
6.1.2.1 Group call control states at the MS side of the interface . 10
6.1.2.1.1 Attributes and parameters of GCC in the MS . 10
6.1.2.1.2 NULL (U0) . 10
6.1.2.1.3 MM CONNECTION PENDING (U0.p) . 10
6.1.2.1.4 GROUP CALL INITIATED (U1) . 10
6.1.2.1.5 GROUP CALL ACTIVE (U2) . 11
6.1.2.1.6 GROUP CALL PRESENT (U3) . 11
6.1.2.1.7 GROUP CALL CONNECTION REQUESTED (U4) . 11
6.1.2.1.8 TERMINATION REQUESTED (U5) . 11
6.1.2.1.9 Sub-states of the Group call active state . 11
6.1.2.1.10 GCC Timers in the MS . 12
6.1.2.1.11 Consistency of parameters and states . 12
6.1.2.2 Group call control states at the network side of the interface . 13
6.1.2.2.1 NULL (State N0) . 13
6.1.2.2.2 GROUP CALL INITIATED (N1) . 13
6.1.2.2.3 GROUP CALL ACTIVE (N2) . 13
6.1.2.2.4 GROUP CALL ESTABLISHMENT PROCEEDING (N3) . 13
6.1.2.2.5 TERMINATION REQUESTED (N4) . 13
6.2 Procedures for establishment of a group call . 13
6.2.1 Activation of a group call by the network . 13
6.2.2 Mobile originated establishment . 13
6.2.2.1 Termination during mobile originated establishment . 14
6.2.2.2 Abnormal cases . 15
6.2.3 Mobile terminating group call establishment in the MS . 15
6.3 Procedures during the active state of a group call . 15
6.3.1 Mobile station procedures in the active state . 15
6.3.1.1 Sub-state transitions in the MS . 15
6.3.2 Network procedures in the active state . 16
6.4 Procedures for release, abortion, and termination of a group call . 16
6.4.1 Termination procedure . 16
6.4.2 Abort and release procedures . 17
6.5 Miscellaneous procedures . 17
6.5.1 Status procedures . 17
6.5.1.1 Get status procedure . 17
6.5.1.2 Set parameter procedure . 17
7 Handling of unknown, unforeseen, and erroneous protocol data . 17
7.1 General . 17
ETSI

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3GPP TS 44.068 version 14.0.0 Release 14 4 ETSI TS 144 068 V14.0.0 (2017-04)
7.2 Message too short . 18
7.3 Unknown or unforeseen transaction identifier . 18
7.4 Unknown or unforeseen message type . 18
7.5 Non-semantical mandatory information element errors . 18
7.6 Unknown and unforeseen information elements in the non-imperative message part . 19
7.6.1 Information elements unknown in the message . 19
7.6.2 Out of sequence information elements. 19
7.6.3 Repeated Information elements . 19
7.7 Non-imperative message part errors . 19
7.7.1 Syntactically incorrect optional Information elements . 19
7.8 Messages with semantically incorrect contents . 19
8 Message functional definitions and contents . 20
8.1 CONNECT . 21
8.1.1 SMS indications . 21
8.2 GET STATUS . 21
8.2.1 mobile identity . 22
8.3 IMMEDIATE SETUP . 22
8.3.1 Mobile identity . 22
8.3a IMMEDIATE SETUP 2 . 23
8.3a.1 TMSI . 23
8.3a.2 Compressed otdi . 23
8.4. SET PARAMET ER . 23
8.5 SETUP . 24
8.5.1 Originator-to-dispatcher information . 24
8.5.2 Talker priority requested . 24
8.6 STATUS . 24
8.6.1 Call state . 25
8.6.2 State attributes . 25
8.7 TERMINATION . 25
8.8 TERMINATION REJECT . 25
8.9 TERMINATION REQUEST . 26
8.9.1 Talker priority . 26
9 Contents of information elements value parts . 26
9.1 Protocol Discriminator . 26
9.2 Transaction identifier . 26
9.3 Message Type . 27
9.4 Other information elements . 27
9.4.1 Call Reference . 27
9.4.2 Call state . 28
9.4.3 Cause . 29
9.4.4 Originator indication . 30
9.4.5 Not used . 31
9.4.6 Spare Half Octet . 31
9.4.7 State attributes . 31
9.4.8 Compressed otdi . 31
9.4.9 Talker priority . 32
9.4.10 SMS indications . 32
Annex A (informative): Example of the coding of the user-user information after
decompression of the originator-to-dispatcher information . 34
Annex B (informative): Change History . 35
History . 36

ETSI

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3GPP TS 44.068 version 14.0.0 Release 14 5 ETSI TS 144 068 V14.0.0 (2017-04)
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

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3GPP TS 44.068 version 14.0.0 Release 14 6 ETSI TS 144 068 V14.0.0 (2017-04)
1 Scope
The present document specifies the Group Call Control (GCC) protocol used by the Voice Group Call Service (VGCS)
on the radio interface.
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.
[1] Void
[1a] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 42.068: "Voice Group Call Service (VGCS); Stage 1".
[3] 3GPP TS 23.003: "Numbering, addressing and identification".
[4] 3GPP TS 23.067: "enhanced Multi-Level Precedence and Pre-emption service (eMLPP); Stage 2".
[5] 3GPP TS 43.068: "Voice Group Call Service (VGCS); Stage 2".
[6] 3GPP TS 44.006: "Mobile Station - Base Stations System (MS - BSS) Interface; Data Link (DL)
Layer Specification ".
[7] 3GPP TS 24.007: "Mobile radio interface signalling layer 3; General aspects".
[8] 3GPP TS 44.018: "Mobile radio interface layer 3 specification; Radio Resource Control Protocol".
[9] 3GPP TS 24.008: "Mobile radio interface Layer 3 specification; Core network protocols; Stage 3".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document the terms and definitions given in 3GPP TS 42.068 and the following apply:
attachment of the user connection: See 3GPP TS 24.008, subclause 5.2.
calling user: GCC entity in the Mobile Station (MS) initiating or having initiated a group call.
clearing the context related to the group call establishment: all running GCC timers in the relevant GCC entity are
stopped, all attributes in the relevant GCC entity are deleted.
downlink: network to mobile station direction.
group call: is used in the same sense as "voice group call".
group call channel: combined uplink/downlink to be allocated in each cell of the group call area for a particular group
call. The uplink can be used by the presently talking service subscriber only. All MSs of the listening service
subscribers in one cell shall listen to the common downlink.
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3GPP TS 44.068 version 14.0.0 Release 14 7 ETSI TS 144 068 V14.0.0 (2017-04)
group receive mode: See 3GPP TS 44.018.
originating mobile station: mobile station initiating or having initiated the group call.
NOTE 1: In certain situations, a MS assumes to be the originating MS of a group call without actually being the
originating MS of that group call.
NOTE 2: There may be one or none originating MS for a given group call.
uplink: mobile station to network direction.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [1a] and the following apply:
BSS Base Station System
eMLPP enhanced Multi-Level Precedence and Pre-emption service
GCC Group Call Control
GPRS General Packet Radio Service
MS Mobile Station
VGCS Voice Group Call Service
CM Connection Management
TI Transaction Identifier
4 Applicability
Support of the group call protocol is optional in the MS and in the network.
5 Main concepts
The present document describes the group call control (GCC) protocol, which is one of the protocols of the Connection
Management (CM) sublayer (see 3GPP TS 24.007).
There is in general more than one MS engaged in a group call. Consequently, there is in general more than one MS with
a GCC entity engaged in the same group call, and there is one GCC entity in the network engaged in that group call.
Under which conditions a GCC message is passed from lower (sub-)layers to the GCC entity is defined in the
specifications of the sub-layers.
The MS shall ignore GCC messages that it receives which were sent in unacknowledged mode and which explicitly
specify as destination a mobile identity which is not a mobile identity of the MS.
Higher layers and the MM sub-layer decide when to accept parallel GCC transactions and when/whether to accept GCC
transactions in parallel to other CM transactions.
The group call may be initiated by a mobile user or by a dispatcher. Specification of a protocol for dispatchers is out of
the scope of the present document. Hence, in the scope of the present document, there are:
- one GCC entity in the network; and
- one or more than one GCC entities in different MSs;
engaged in a group call, and one ore none of the MSs is the originator of the group call (called the originating MS in the
present document). Note that, in certain situations, a MS assumes to be the originator of a group call without being the
originator.
The originator of the GCC transaction chooses the Transaction Identifier (TI). A MS not assuming to be the originator
of the transaction will chose the transaction identifier received from the network, setting the TI flag to 1+x mod 2 where
x is the received TI flag.
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3GPP TS 44.068 version 14.0.0 Release 14 8 ETSI TS 144 068 V14.0.0 (2017-04)
The present document describes the group call control protocol only with regard to two peer entities, one in a MS, the
other one in the network. The call control entities are described as communicating finite state machines which exchange
messages across the radio interface and communicate internally with other protocol (sub)layers. In particular, the GCC
protocol uses the MM and RR sublayer specified in 3GPP TS 24.008 and 3GPP TS 44.018. This description in only
normative as far as the consequential externally observable behaviour is concerned. For simplicity, instead of using the
terms "GCC entity in the MS" and "GCC entity in the network", the present document often uses the terms "MS" and
"network" if no confusion may arise.
Certain sequences of actions of the two peer entities compose "elementary procedures" which are used as a basis for the
description in the present document. These elementary procedures are defined in clause 6.
The network should apply supervisory functions to verify that the GCC procedures are progressing and if not, take
appropriate means to resolve the problems. This, however, is out of the scope of the present document.
6 Elementary procedures for Group Call Control
6.1 Overview
6.1.1 General
The elementary procedures may be grouped into the following classes:
- group call establishment procedures;
- group call termination procedures;
- call information phase procedures;
- miscellaneous procedures.
Figure 6.1 gives an overview of the main states and transitions on the MS side.
ETSI

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