12 Content of messages

3GPP43.069Release 17Stage 2TSVoice Broadcast Service (VBS)

This clause specifies the content of the following messages:

On the B interface (MSC-VLR):

– Allocate Group Call Number;

– Allocate Group Call Number ack;

– Allocate Group Call Number negative response;

– Release Group Call Number.

On the E interface (MSC-MSC):

– Prepare Group Call;

– Prepare Group Call ack;

– Prepare Group Call negative response;

– Send Group Call End Signal;

– Send Group Call Info;

– Send Group Call Info ack;

– Send Group Call Info negative response.

On the I interface (MSC-GCR):

– GCR Interrogation;

– GCR Interrogation ack;

– GCR Interrogation negative response;

– Call Released.

On the GCR-GCR-interface:

– Sync GCR ;

– Sync GCR ack;

– Sync GCR negative response.

In the tables which follow, information elements are shown as Mandatory (M), Conditional (C) or Optional (O). A mandatory information element shall always be present. A conditional information element shall be present if certain conditions are fulfilled; if those conditions are not fulfilled it shall be absent. An optional element may be present or absent, at the discretion of the application at the sending entity.

12.1 Messages on the B interface (MSC-VLR)

12.1.1 Allocate Group Call Number

No information element is required.

12.1.2 Allocate Group Call Number ack

The following information element is required.

Information element name

Required

Description

Group Call number

M

E.164 number required to route the call from the anchor MSC to the relay MSC

12.1.3 Allocate Group Call Number negative response

The negative response information element can takes the following value:

– No Group Call number available.

12.1.4 Release Group Call Number

The following information element is required.

Information element name

Required

Description

Group Call number

M

E.164 number required to route the call from the anchor MSC to the relay MSC

12.2 Messages on the E interface (MSC-MSC)

12.2.1 Prepare Group Call

The following information elements are required.

Information element name

Required

Description

Teleservice

M

The teleservice Voice Broadcast Call indicates that a VBS call has to be prepared

Broadcast call reference

M

see clause 9

Ciphering Algorithm, Group Key and Number

M

information on the cipher algorithm and group key to be used

Priority

C

The default priority level must be present if eMLPP applies

Codec Info

M

Information on the codecs allowed for the VBS call

Uplink Reply Indicator

O

Indicates that the uplink reply procedure is applicable for the voice broadcast call. Must be present if the GCR provides the corresponding information.

12.2.2 Prepare Group Call ack

The following information element is required.

Information element name

Required

Description

Group Call number

M

E.164 number required to route the call from the anchor MSC to the relay MSC

12.2.3 Prepare Group Call negative response

The negative response information element can takes the following value:

– No Group Call number available.

12.2.4 Send Group Call End Signal

The following information element is required.

Information element name

Required

Description

IMSI

C

The IMSI of the service subscriber who has initiated the call. Must be present if the call was initiated by a service subscriber in the relay MSC area.

12.2.5 Send Group Call Info

The following information elements are required.

Information element name

Required

Description

Teleservice

M

The teleservice Voice Broadcast Call indicates that the request is for VBS

Requested Info

M

Indicates that

Anchor MSC Address and Broadcast Call Reference

are requested

Group ID

M

see clause 9.

Cell Id

M

Identification of the cell where the group call initiating service subscriber is located.

IMSI

M

IMSI of the service subscriber for whom the request is sent.

12.2.6 Send Group Call Info ack

The following information elements are required.

Information element name

Required

Description

Anchor MSC Address

M

E.164 number required to route the call from the VMSC to the anchor MSC.

Broadcast call reference

M

see clause 9.

12.2.7 Send Group Call Info negative response

The negative response information element can take the following value:

– ongoing call;

– failure.

12.3 Messages on the I interface (MSC-GCR)

12.3.1 GCR Interrogation

The following information elements are required.

Information element name

Required

Description

Broadcast call reference

C

see clause 9. Must be present if the VBS call was initiated by a dispatcher or by a service subscriber in the relay MSC area and the receiving GCR is associated to the anchor MSC, or if the receiving GCR is associated to a relay MSC and the GCR interrogation was triggered by a Prepare Group Call message received from the anchor MSC.

Group ID

C

see clause 9. Must be present if one of the following conditions is fulfilled:

1) the MSC is the visited MSC of the service subscriber initiating the VBS call, except if the MSC is a relay MSC and the GCR interrogation was triggered by a Prepare Group Call message received from the anchor MSC;

2) the GCR interrogation was triggered by a Send Group Call Info message received from the VMSC.

Originating Cell ID

C

see clause 9. Must be present if one of the following conditions is fulfilled:

1) the MSC is the visited MSC of the service subscriber initiating the VBS call, except if the MSC is a relay MSC and the GCR interrogation was triggered by a Prepare Group Call message received from the anchor MSC;

2) the GCR interrogation was triggered by a Send Group Call Info message received from the VMSC.

CLI

C

Calling Line Identity of the initiating dispatcher, or VBS prefix plus broadcast call reference in case of service subscriber originated VBS call in the relay MSC. Must be present if the MSC is not the visited MSC of the service subscriber initiating the VBS call.

Relay MSC indicator

M

A flag indicating whether the GCR interrogation was triggered from a Prepare Group Call message received from the anchor MSC

Group Call Serving MSC indicator

C

A flag indicating whether the GCR interrogation was triggered from a Send Group Call Info message received from the VMSC. May be set to "yes" in a RANflex configuration (with or without group call redundancy) only.

IMSI

C

IMSI of the service subscriber who has initiated the VBS call. Must be present if the MSC is the visited MSC of the service subscriber initiating the VBS call, or the GCR interrogation was triggered by a Send Group Call Info message received from the VMSC

Uplink Reply Indicator

O

Indicates that the uplink reply procedure is applicable for the voice broadcast call. Must be present if the MSC is the anchor MSC and the related flag exists and is set in the GCR.

Ongoing Call Override Indication

C

Indicates that the GCR shall delete any ongoing call information before processing the request.

May be set to "yes" in a RANflex configuration with group call redundancy only.

12.3.2 GCR Interrogation ack

The following information elements are required.

Information element name

Required

Description

Broadcast Call Reference

C

Must be present if the GCR receives an interrogation request containing a Group ID and an Originating Cell ID.

Cell List

C

A list of cells inside the MSC area into which the call is to be sent. Must be present if a) no anchor MSC address is present in the broadcast call reference record and the GCR interrogation was not triggered by a Send Group Call Info message, or b) the relay MSC indicator was set in the GCR Interrogation message

Anchor MSC Address

C

E.164 number required to route the call from the relay MSC and in a RANflex configuration (with or without group call redundancy) from the VMSC to the anchor MSC. Must be present if the anchor MSC Address is present in the broadcast call reference record

Relay MSC List

C

A list of relay MSCs into which the call is to be sent. Must be present if a relay MSC list is present in the broadcast call reference record and the GCR interrogation was not triggered by a Send Group Call Info message

Group Key and Number

C

Information on the cipher algorithm and the group key to be used. Must be present if Group Key and Number is present in the broadcast call reference record and the GCR interrogation was not triggered by a Send Group Call Info message

Codec Info

C

Information on the codecs allowed for the voice broadcast call. Must be present if Codec Info is present in the broadcast call reference record and the GCR interrogation was not triggered by a Send Group Call Info message

Establish to Dispatcher List

C

A list of identities of dispatchers to which a dedicated link is to be established. Must be present if included in the broadcast call reference record. Note that the CLI possibly received with the GCR interrogation message must not be included

Release from Dispatcher List

C

A list of identities of dispatchers which are allowed to terminate the voice broadcast call. Must be present if included in the broadcast call reference record and the GCR interrogation was not triggered by a Send Group Call Info message

Priority

C

The default priority level related to the voice broadcast call if eMLPP applies. Must be present if included in the broadcast call reference record and the GCR interrogation was not triggered by a Send Group Call Info message

IMSI

C

IMSI of the service subscriber who has initiated the VBS call. Must be present if the Relay MSC Indicator was set in the GCR interrogation message and the IMSI is present in the broadcast call reference record

Originating Cell ID

C

Must be present if originating cell id is present in the broadcast call reference record

12.3.3 GCR interrogation negative response

The negative response information element can take the following values:

– on-going call. In a RANflex configuration with group call redundancy the MSC address of the MSC within the redundancy pool at which the group call is ongoing shall be present in the negative response; and

– failure.

12.3.4 Call released

The following information element is required.

Information element name

Required

Description

Broadcast call reference

M

see clause 9

12.4 Messages on the GCR – GCR interface

12.4.1 Sync GCR

The following information elements are required.

Information element name

Required

Description

Teleservice

M

The teleservice Voice Broadcast Service indicates that a VBS call has to be prepared

Group call reference

M

see clause 9

Initial Talker Information

C

see subclause 8.1.3.2

on-going indication

C

indicates by its present that the broadcast call is ongoing

MSC Address

C

Address of the sending GCR’s associated MSC, at which the broadcast call is ongoing.

call released indication

C

indicates by its presence that the broadcast call is no longer ongoing.

override indication

C

indicates by its presence that the receiving GCR shall replace the stored MSC-Address with the received value.

request indication

C

indicated by its presence that the sending GCR requests ongoing information and MSC Address from the receiving GCR

12.4.2 Sync GCR ack

The following information elements are required.

Information element name

Required

Description

Status of the voice group call

C

Indicating whether the voice broadcast call is established or not.

MSC Address

C

Address of the MSC, at which the broadcast call is ongoing.

Initial Talker Information

C

see subclause 8.1.3.2

12.4.3 Sync GCR negative response

The negative response information element can take the following values:

– on-going call. The MSC address of the MSC within the redundancy pool at which the broadcast call is ongoing shall be present in the negative response;

– initial talker information; and

– failure.