Content for TR 23.700-76 Word version: 18.0.0

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0 Introduction p. 5

The ad hoc group call allows authorised users to combine a set of MCX users based on implementation-specific criteria into a group call. The main characteristics of this ad hoc group call are:

The ad hoc group does not exist until it is spontaneously created during the call.
The ad hoc group ceases to exist when the call terminates.
The ad hoc group does not support 'persistent state' communication, e.g. emergency state.

MCX users that are combined in an ad hoc group call can be served by the same or different MCX systems. The ad hoc group call uses a common security level, priority level, floor control method, and set of operational characteristics for the participants during the call. As with any group call, the priority level can change dynamically.

The ad hoc group is used for a single call and it does not persist when the call is terminated. Authorized users can recreate the ad hoc group for subsequent calls, or request creation of a permanent MCX group from the participants in the ad hoc group call.

This technical report identifies the key issues and corresponding solutions with recommendations for the normative work.

1 Scope p. 6

The present document studies solutions to satisfy the requirements identified to support Ad hoc group communication for MCX services. It identifies enhancements to be included in the technical specifications for MCPTT, MCVideo, MCData and in the common functional architecture to support Ad hoc group communications. Requirements for this study are taken from TS 22.280.

2 References p. 6

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]

TR 21.905: "Vocabulary for 3GPP Specifications".

[2]

TS 22.179: "Mission Critical Push to Talk (MCPTT); Stage 1".

[3]

TS 22.280: "Mission Critical Services Common Requirements (MCCoRe)".

3 Definitions of terms, symbols and abbreviations p. 6

3.1 Terms p. 6

For the purposes of the present document, the terms given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

Ad hoc Group Communication:

The combining of a multiplicity of MCX Users into a group for the duration of a communication and when the communication is terminated the group no longer exists.

For the purposes of the present document, the following terms given in TS 22.280 apply

MCX UE

MCX User

Mission Critical

Mission Critical Service

Functional alias

3.2 Symbols p. 6

For the purposes of the present document, the following symbols apply:

3.3 Abbreviations p. 7

For the purposes of the present document, the abbreviations given in TR 21.905 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.