Content for  TS 23.280  Word version:  17.5.0

10.7  Use of MBMS transmission  Word‑p. 127

10.7.1  General

This subclause defines information flows and procedures for MBMS usage that applies to MC services. MBMS bearers can be used by any MC service for any MC service group. A single MBMS bearer can be used for one or more MC services within a single group or by multiple group communications in parallel.

The following subclauses specify the procedures and information flows for the usage of MBMS transmission that are utilised by the following MC services:

• MCPTT (as specified in TS 23.379);
• MCVideo (as specified in TS 23.281); and
• MCData (as specified in TS 23.282).

MC service specific pre-requisites and resultant behaviour by functional entities in performing these procedures are specified in the respective MC service TSs as listed above.

10.7.2  Information flows for MBMS transmission

10.7.2.1  MBMS bearer announcement

Table 10.7.2.1-1 describes the information flow MBMS bearer announcement from the MC service server to the MC service client.

Table 10.7.2.1-1: MBMS bearer announcement

Information element	Status	Description
TMGI	M	TMGI information
Alternative TMGI	O	A list of additional alternative TMGI may be included and used in roaming scenarios.
QCI	O	QCI information used by the ProSe UE-Network Relay to determine the ProSe Per-Packet Priority value to be applied for the multicast packets relayed to Remote UE over PC5
List of service area identifier	M	A list of service area identifier for the applicable MBMS broadcast area.
Frequency	O	Identification of frequency if multi carrier support is provided
SDP information	M	SDP with media and floor control information applicable to groups that can use this bearer (e.g. codec, protocol id, FEC information)
Monitoring state	O	The monitoring state is used to control if the client is actively monitoring the MBMS bearer quality or not.
Announcement acknowledgment	O	Indicate if the MBMS server requires an acknowledgement of the MBMS bearer announcement.
Unicast status	O	An indication that the listening status of the unicast bearer is requested.
ROHC information	O	Indicate the usage of ROHC and provide the parameters of the ROHC channel to signal to the ROHC decoder.

10.7.2.2  MBMS listening status report  Word‑p. 128

Table 10.7.2.2-1 describes the information flow for the MBMS listening status report from MC service client to MC service server. The information is used for the decision on the switching from MBMS bearer to unicast bearer or vice versa.

Table 10.7.2.2-1: MBMS listening status report

Information element	Status	Description
MC service ID	M	The identity of the MC service user who wants to report the MBMS listening status.
TMGI(s)	M	TMGI(s) information.
MBMS listening status(s)	M	The MBMS listening status per TMGI.
MBMS reception quality level	O	The reception quality level per TMGI (see NOTE)
Unicast listening status	O	The unicast listening status.

10.7.2.3  MBMS suspension reporting instruction

Table 10.7.2.3-1 describes the information flow for the MBMS suspension reporting instruction from MC service server to MC service client in a unicast bearer for MBMS suspension reporting.

Table 10.7.2.3-1: MBMS suspension reporting instruction (unicast)

Information element	Status	Description
MC service ID	M	The MC service identity
Suspension reporting	M	Enables or disable the suspension reporting for a specific MC service client

Table 10.7.2.3-2 describes the information flow for the MBMS suspension reporting instruction from MC service server to MC service client in a multicast bearer for MBMS suspension reporting.

Table 10.7.2.3-2: MBMS suspension reporting instruction (multicast)

Information element	Status	Description
Suspension reporting client subset	M	Contains a uniquely defined subset of MC service clients that shall report MBMS suspension

10.7.2.4  Discover bearer request  Word‑p. 129

Table 10.7.2.4-1 describes the information flow discover bearer request from the MC service server to another MC service server (MBMS bearer control role).

Table 10.7.2.4-1: Discover bearer request

Information element	Status	Description
List of service area identifiers	M	A list of service area identifier for the applicable MBMS broadcast area.
Bandwidth	M	Maximum bandwidth required
QCI	O	Desired QCI

10.7.2.5  Discover bearer response

Table 10.7.2.5-1 describes the information flow discover bearer response from an MC service server (MBMS bearer control role) to the MC service server.

Table 10.7.2.5-1: Discover bearer response

Information element	Status	Description
TMGIs	M	List of TMGIs and related information
List of service area identifiers	M	A list of service area identifiers for the applicable MBMS broadcast areas, corresponding to the listed TMGIs, over which the request was successful.
Frequency	O	Identification of the frequency if multi-carrier support is provided
QCI	O	QCI information used by the ProSe UE-Network relay to determine the ProSe per-packet priority value to be applied for the multicast packets relayed to a remote UE over PC5.

10.7.2.6  Media distribution request

Table 10.7.2.6-1 describes the information flow media distribution request from the MC service server to an MC service server (MBMS bearer control role) that has a desired bearer.

Table 10.7.2.6-1: Media distribution request

Information element	Status	Description
TMGI	M	TMGI information
Bandwidth	M	Maximum bandwidth required
Separate floor control	M	Whether or not a separate bearer is required for floor control
SDP information	M	SDP with media and floor control information applicable to groups that can use this bearer (e.g. codec, protocol id)
QCI	O	Desired QCI
MC Group ID	O	The MC group id for when the request is sent for a specific group call.

10.7.2.7  Media distribution request response  Word‑p. 130

Table 10.7.2.7-1 describes the information flow media distribution response from an MC service server (MBMS bearer control role) that has a desired bearer to the MC service server.

Table 10.7.2.7-1: Media distribution response

Information element	Status	Description
TMGI	M	TMGI information
Bandwidth	M	Maximum bandwidth required
SDP information	M	SDP with media and floor control information applicable to groups that can use this bearer (e.g. codec, protocol id)
QCI	O	Actual QCI
Media stream identifier	O	This element identifies the media stream of the SDP used for the group call (e.g. MBMS subchannel).
Media distribution indicator	O	Indicates to the MC service server whether the media in the ongoing group communication should be sent or not

10.7.2.8  Identify multicast participants request

Void

10.7.2.9  Remove call from bearer request

Void

10.7.2.10  Media distribution release |R15|

Table 10.7.2.10-1 describes the information flow media distribution release from the MC service server to an MC service server (MBMS bearer control role) that has the used bearer.

Table 10.7.2.10-1: Media distribution request

Information element	Status	Description
TMGI	M	TMGI information
Bandwidth	M	The bandwidth released by the MC service server that used the bearer
MC Group ID	O	The MC group id for when the request is sent for a specific group call.

10.7.2.11  Media broadcasting notification |R15|

Void.

10.7.2.12  Group status notification |R16|

Table 10.7.2.12-1 describes the information flow for the group status notification from MC service server to MC service client.

Table 10.7.2.12-1: Group status notification

Information element	Status	Description
MC service group ID	M	The MC service group ID of the group
Status of the group	M	Indicate the group has on-going call or not