ETSI TR 103 565-1 V1.2.1 (2018-12)

ETSI TR 103 565-1 V1.2.1 (2018-12)






TECHNICAL REPORT
TETRA and Critical Communications Evolution (TCCE);
Interworking between TETRA and 3GPP
mission critical services
Part 1: General considerations for interworking

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2 ETSI TR 103 565-1 V1.2.1 (2018-12)



Reference
RTR/TCCE-04196
Keywords
mission critical communication, radio, TETRA,
V+D
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3 ETSI TR 103 565-1 V1.2.1 (2018-12)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definition of terms and abbreviations . 7
3.1 Terms . 7
3.2 Abbreviations . 8
4 Service overview . 8
4.1 Services . 8
4.2 Interworking realization . 9
5 Considerations . 10
5.1 General . 10
5.2 Addressing . 10
5.2.1 TETRA and MCPTT addressing . 10
5.2.2 Interconnection and migration . 11
5.2.3 Identification of calling or talking party . 11
5.3 Speech group calls . 12
5.3.1 Group affiliation (group attachment) . 12
5.3.2 Controlling systems . 12
5.3.3 Group linking . 12
5.3.3.1 Overview . 12
5.3.3.2 Interworking function as proxy group member . 13
5.3.3.3 Interworking function as proxy TETRA SwMI/MCPTT server . 13
5.3.4 Single group across both systems . 14
5.3.5 Group patching . 15
5.3.6 Group regrouping . 15
5.3.7 Group call types . 16
5.3.8 Call queuing . 16
5.4 Individual calls . 17
5.5 Floor control . 17
5.6 Emergency calls and alerts . 17
5.7 Priorities . 17
5.8 Supplementary services . 18
5.8.1 General . 18
5.8.2 Call forwarding . 18
5.8.3 Late entry . 18
5.8.3.1 Late entry for clients within each system . 18
5.8.3.2 Late entry between systems. 18
5.8.4 DGNA . 19
5.8.4.1 User regrouping . 19
5.8.4.2 Group regrouping . 19
5.9 Short Data Service . 19
5.9.1 General . 19
5.9.2 Format conversion in the IWF of TETRA SDSs to MCData SDSs . 19
5.9.3 Format conversion in the IWF of MCData SDSs to TETRA SDSs . 20
5.9.4 Message references . 20
5.9.5 Delivery reports . 20
5.9.6 SDS length management by the IWF . 20
5.10 Status and alerts . 21
ETSI

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4 ETSI TR 103 565-1 V1.2.1 (2018-12)
5.10.1 Status coding . 21
5.10.2 Emergency alert . 22
5.10.3 Callback request . 22
5.11 Speech coding . 22
5.12 Media encapsulation . 23
5.13 Security aspects . 23
5.13.1 Service authorization . 23
5.13.2 User authentication . 23
5.13.3 Interface authentication . 23
5.13.4 Media encryption and key management . 23
Annex A: Implications for MCPTT from interworking service . 25
A.1 General . 25
A.2 Interworking implications for MCPTT . 25
A.2.1 MCPTT group call models . 25
A.2.2 Talking party identity restriction . 25
A.2.3 Resource queuing . 25
A.2.4 SDS message rejection . 25
A.2.5 Codec configuration . 25
A.2.6 Private call keys . 26
A.2.7 Delivery of TETRA keys . 26
A.2.8 Late entry. 26
History . 27


ETSI

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5 ETSI TR 103 565-1 V1.2.1 (2018-12)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee TETRA and Critical Communications
Evolution (TCCE).
The present document is part 1 of a multi-part deliverable covering interworking between TETRA and 3GPP mission
critical services, as identified below:
Part 1: "General considerations for interworking";
Part 2: "Security of interworking between TETRA and Broadband applications".
Modal verbs terminology
In the present document "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
3GPP is standardizing a set of mission critical services as applications working over 3GPP LTE systems. These services
include speech PTT systems (MCPTT), data (MCData) and video (MCVideo) systems. Users have a need to interwork
between TETRA and 3GPP MC systems for a number of reasons which can include:
• Communication between different user groups who receive service from the different types of system.
• Use of both systems by the same set of users to allow selection of optimum radio coverage and services in any
situation.
• Migration from an existing TETRA system to a 3GPP MC system over a period of time, which may be long.
It is envisaged that an interworking function will be standardized as part of this work within ETSI TCCE to allow
communication between TETRA and 3GPP MC systems. The present document provides considerations for realizing
this interface.
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6 ETSI TR 103 565-1 V1.2.1 (2018-12)
1 Scope
The present document contains scenarios and considerations for an interworking function between TETRA and 3GPP
MC services.
2 References
2.1 Normative references
Normative references are not applicable in the present document.
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
referenced 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 EN 300 392-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 2: Air
Interface (AI)".
NOTE: The latest version of either ETSI EN 300 392-2 or ETSI TS 100 392-2 applies.
[i.2] ETSI TR 102 022-2: "User Requirements Specification; Mission Critical Broadband
Communications; Part 2: Critical Communications Application".
[i.3] ETSI EN 300 392-1: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 1:
General network design".
[i.4] Recommendation ITU-T E.218: "Management of the allocation of terrestrial trunk radio Mobile
Country Codes".
[i.5] IETF RFC 3986: "Uniform Resource Identifier (URI): Generic Syntax".
[i.6] ETSI EN 300 392-3 (all sub-parts): " Terrestrial Trunked Radio (TETRA); Voice plus Data
(V+D); Part 3: Interworking at the Inter-System Interface (ISI)".
NOTE: The referenced document has multiple parts; all parts are relevant.
[i.7] ETSI TS 123 280: "LTE; Common functional architecture to support mission critical services;
Stage 2 (3GPP TS 23.280)".
[i.8] ETSI TS 123 379: "LTE; Functional architecture and information flows to support Mission
Critical Push To Talk (MCPTT); Stage 2 (3GPP TS 23.379)".
[i.9] ETSI TS 123 281: "LTE; Functional architecture and information flows to support Mission
Critical Video (MCVideo); Stage 2 (3GPP TS 23.281)".
[i.10] ETSI TS 123 282: "LTE; Functional architecture and information flows to support Mission
Critical Data (MCData); Stage 2 (3GPP TS 23.282)".
[i.11] TETRA + Critical Communications Association: "TETRA Interoperability Profile (TIP);
Part 1: Core".
NOTE: Available at https://tandcca.com/interoperability/specifications-for-interoperability/.
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7 ETSI TR 103 565-1 V1.2.1 (2018-12)
[i.12] ETSI TS 126 201: "Digital cellular telecommunications system (Phase 2+) (GSM); Universal
Mobile Telecommunications System (UMTS); LTE; Speech codec speech processing functions;
Adaptive Multi-Rate - Wideband (AMR-WB) speech codec; Frame structure (3GPP TS 26.201)".
[i.13] IETF RFC 4867: "RTP Payload Format and File Storage Format for the Adaptive Multi-Rate
(AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs".
[i.14] ETSI TS 100 392-3-8: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 3: Interworking at the Inter-System Interface (ISI); Sub-part 8: Generic Speech Format
Implementation".
[i.15] ETSI EN 302 109: "Terrestrial Trunked Radio (TETRA); Security; Synchronization mechanism
for end-to-end encryption".
[i.16] 3GPP TR 23.781: "Study on migration and interconnection for mission critical services".
[i.17] 3GPP TR 23.782: "Study on mission critical communication interworking between LTE and
non-LTE systems".
[i.18] ETSI TS 124 379: "LTE; Mission Critical Push To Talk (MCPTT) call control; Protocol
specification (3GPP TS 24.379)".
3 Definition of terms and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in ETSI EN 300 392-2 [i.1] and the following apply:
controlling system: system responsible for call control, policy enforcement, floor control management and media
distribution in a call
NOTE: A system may take either a controlling or a participating role in different circumstances.
group affiliation: mechanism by which a user's interest in one or more groups is determined
NOTE: Terminology used in 3GPP mission critical services; equivalent to TETRA group attachment.
group attachment: mechanism by which a user's interest in one or more groups is determined
NOTE: Terminology used in TETRA; equivalent to 3GPP group affiliation.
interconnection: means of communication between two systems whereby users obtaining service from one system can
communicate with users who are obtaining service from one or more other systems where the systems use similar
technologies
interworking: means of communication between two systems whereby users obtaining service from one system can
communicate with users who are obtaining service from one or more other systems where the systems use different
technologies
MCData: mission critical data service standardized in 3GPP
MCPTT: mission critical push to talk speech service standardized in 3GPP
MCVideo: mission critical video service standardized in 3GPP
migration: means for a user with a subscription to a first system to obtain service directly from a second system whilst
making use of the subscription to the first system
participating system: system responsible for call control, floor control management and media distribution on behalf
of its served users under the control of the controlling system
NOTE: A system may take either a controlling or a participating role in different circumstances.
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8 ETSI TR 103 565-1 V1.2.1 (2018-12)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
rd
3GPP 3 Generation Partnership Project
ACELP Algebraic Code-Excited Linear Prediction
AMR-WB Adaptive Multi Rate - Wide Band
ASSI Alias Short Subscriber Identity
BS Base Station
codec coder-decoder
DGNA Dynamic Group Number Assignment
DTX Discontinuous Transmission
FFS For Further Study
GSSI Group Short Subscriber Identity
GTSI Group TETRA Subscriber Identity
ID IDentity
IP Internet Protocol
ISI Inter System Interface
ISSI Individual Short Subscriber Identity
ITSI Individual TETRA Subscriber Identity
IWF Inter Working Function
MC Mission Critical
MCC Mobile Country Code
MCPTT Mission Critical Push To Talk
MNC Mobile Network Code
MNI Mobile Network Identity
MS Mobile Station
PTT Push To Talk
QoS Quality of Service
RFC Request For Comment
RTP Real Time Protocol
SDS Short Data Service
SDS-TL Short Data Service - Transport Layer
SIP Session Initiation Protocol
SSI Short Subscriber Identity
SwMI Switching and Management Infrastructure
TCCA TETRA and Critical Communications Association
TETRA TErrestrial Trunked RAdio
TIP TETRA Interoperability Profile
TX Transmitter
URI Uniform Resource Identifier
4 Service overview
4.1 Services
User requirements are specified in ETSI TR 102 022-2 [i.2].
The following services are required to be carried across an interworking function between TETRA and 3GPP MC
services:
a) Individual call - duplex and semi duplex.
b) Group call.
c) Variants of these, such as emergency calls and broadcast calls.
d) Short Data Service.
e) Packet data service (see note).
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9 ETSI TR 103 565-1 V1.2.1 (2018-12)
Users will also require the following supplementary services to be supported:
a) Late entry on either system.
b) Talking party identity, carried between systems.
c) Calling party identity, carried between systems.
d) Restriction of calling and talking party identities carried between systems.
e) Group management on both systems.
f) Further supplementary services as required.
Additional service characteristics to be supported are:
a) Prioritization schemes allowing priority requests to be resolved between systems.
b) Pre-emption.
NOTE: Packet data service interworking is FFS, but may simply make use of IP routing techniques outside the
scope of this study.
Security services such as authentication, air interface encryption and end to end encryption need to be maintained
appropriately.
Note that the TETRA standard supports a wider range of functionality than the set that is required for interworking with
mission critical applications over broadband. Also, some aspects of services within the TETRA standard are not
commonly utilized within TETRA implementations, and are not specified for interoperability in the TCCA core TIP
[i.11] and accompanying specifications. Aspects of TETRA standard functionality that are not specified for
interoperability in [i.11] or not required for interworking in ETSI TR 102 022-2 [i.2] will not be discussed within the
present document. Additional functionality specified in the interoperability documentation following publication of the
present document may be reflected in future revisions of the present document.
4.2 Interworking realization
The concept of the interworking function can be as shown in figure 4.2-1.

Figure 4.2-1: Concept of the interworking function
The interworking function to be specified as a result of this study will take the TETRA Inter-System Interface, specified
in the ETSI EN 300 392-3 series of specifications [i.6] as a model of the functionality possible between TETRA
systems, and the MCPTT interworking interface, which is expected to be specified within 3GPP Release 15, as inputs.
The interface to the TETRA SwMI could make use of the TETRA ISI, or could be outside the scope of the
standardization process.
The present document is intended to lead to a Technical Specification which specifies the interaction between the
interface between a TETRA MS and a TETRA SwMI under the conditions of inter-system behaviour (shown as (1) in
figure 4.2-1), and the MC system interworking interface (shown as (2) in figure 4.2-1).
The TETRA Inter-System Interface is defined in ETSI EN 300 392-3 [i.6], and an MCPTT to MCPTT interface has
been studied in 3GPP TR 23.781 [i.16]. An MCPTT to non MCPTT interworking interface has been studied in 3GPP
TR 23.782 [i.17].
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10 ETSI TR 103 565-1 V1.2.1 (2018-12)
For the purposes of this study, the interface will be considered to be a single logical interface between each pair of one
MCPTT service and one TETRA SwMI. Any realization of multiple interfaces between a pair of systems e.g. for
resilience is FFS.
NOTE: Interface addressing is considered a lower layer function and is outside the scope of the present document.
5 Considerations
5.1 General
Considerations relating to TETRA - 3GPP MC service interworking are described in this clause.
5.2 Addressing
5.2.1 TETRA and MCPTT addressing
The TETRA standard identifies a subscriber by an Individual TETRA Subscriber Identity ITSI. This consists of a 24 bit
Mobile Network Identifier MNI (consisting of Mobile Country Code MCC and Mobile Network Code MNC), and an
Individual Short Subscriber Identity ISSI. The numbering scheme is described in ETSI EN 300 392-1 [i.3] and the
management of MCC and MNC is specified in Recommendation ITU-T E.218 [i.4].
3GPP MCPTT and MCData specify an MCPTT-ID and an MCData-ID which are a URIs; see ETSI TS 123 280 [i.7],
ETSI TS 123 379 [i.8] and ETSI TS 123 282 [i.10]. A URI is expected to be an alphanumeric string consisting of
individual user part and domain part. The MCPTT-ID and MCData-ID identify the system or systems within which the
MCPTT and MCData user subscriptions are located. There may be no limit on length, however IETF RFC 3986 [i.5]
recommends a maximum length of 255 characters. The 3GPP MC series of specifications also define an MCPTT Group
...