12 Content of messages

03.683GPPStage 2TSVoice Group Call Service (VGCS)

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;

– Forward Group Call Signalling;

– Process Group Call Signalling.

On the I-interface (MSC-GCR):

– GCR Interrogation;

– GCR Interrogation ack;

– GCR Interrogation negative response;

– Call Released.

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 Group Call indicates that a VGCS call has to be prepared.

Group call reference

M

see clause 9

Cipher 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 VGCS call

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 Forward Group Call Signalling

The following information elements are required:

Information element name

Required

Description

IMSI

C

IMSI of the service subscriber who has initiated the call. Must be present if the message is used to transfer the IMSI to the relay MSC.

Uplink Request Acknowledgement flag

C

Must be present if the message is used as positive acknowledgement of an uplink request.

Uplink Release Indication flag

C

Must be present if the message is used to indicate to the relay MSC that the uplink is no longer busy.

Uplink Reject Command flag

C

Must be present if the message is used as negative acknowledgement of an uplink request

Uplink Seized Command flag

C

Must be present if the message is used to indicate to the relay MSC that the uplink has become busy

Uplink Release Command flag

C

Must be present if the message is used to indicate to the relay MSC that the uplink which is currently under control of the relay MSC has to be released.

12.2.6 Process Group Call Signalling

The following information elements are required:

Information element name

Required

Description

Uplink Request flag

C

Must be present if the message is used to request uplink control from the anchor MSC.

Uplink Release Indication flag

C

Must be present if the message is used to indicate to the anchor MSC that the uplink has become free.

Release Group Call flag

C

Must be present if the message is used to indicate to the anchor MSC that the VGCS call shall be released.

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

Group call reference

C

see clause 9. Must be present if the VGCS 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.

Group ID

C

see clause 9. Must be present if the VGCS call was initiated by a service subscriber in the own MSC area.

Originating Cell ID

C

see clause 9. Must be present if the VGCS call was initiated by a service subscriber in the own MSC area.

CLI

C

Calling Line Identity of the initiating dispatcher, or VGCS prefix plus group call reference in case of service subscriber originated VGCS call in the relay MSC. Must be present if the VGCS call was not initiated by a service subscriber located in the own MSC area.

Relay MSC indicator

M

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

IMSI

C

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

12.3.2 GCR Interrogation ack

The following information elements are required:

Information element name

Required

Description

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 group call reference record, 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 to the anchor MSC. Must be present if the anchor MSC Address is present in the group 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 group call reference record

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 group call reference record

Codec Information

C

Information on the codecs allowed for the voice broadcast call. Must be present if Codec Info is present in the group call reference record.

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 group 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 group call. Must be present if included in the group call reference record.

Priority

C

The default priority level related to the voice group call if eMLPP applies. Must be present if included in the group call reference record.

IMSI

C

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

No Activity Time

C

The length of the time over which no activity is detected before the voice group call is automatically terminated.

12.3.3 GCR interrogation negative response

The negative response information element can takes the following value:

– on-going call;

– failure.

12.3.4 Call released

The following information element is required:

Information element name

Required

Description

Group call reference

M

see clause 9.

Annex A (informative):
Change History

TSG#

TSG doc

WG doc

Spec

CR

Rev

Ph

Cat

Old vers

New vers

Title

WI

S#31

Feb 2000

03.68

8.0.0

Specification version upgrade to Release 1999 version 8.0.0

CN#7

email before SMG#32

Apr 2000

03.68

A017

R99

8.0.0

8.1.0

VGCS Signalling Flows

ASCI

CN#7

email before SMG#32

Apr 2000

03.68

A019

R99

8.0.0

8.1.0

Data Flow for Fast Call setup

ASCI

CN#7

email before SMG#32

Apr 2000

03.68

A022

R99

8.0.0

8.1.0

Recommendation to use DTMF tones for VGCS talking subscriber downlink un-muting

ASCI

S#32CN#8

NP-000275

N1-000738

03.68

A024

R99

F

8.1.0

8.2.0

Call Release clarification at the Relay MSC

ASCI

S#32CN#8

NP-000275

N1-000739

03.68

A025

R99

F

8.1.0

8.2.0

Speech transmission architecture clarification

ASCI

S#32CN#8

NP-000275

N1-000740

03.68

A026

R99

D

8.1.0

8.2.0

Clarification of anchor MSC address format

ASCI

CN-21

NP-030408

N1-031202

03.68

A034

1

R99

F

8.2.0

8.3.0

Correction of uplink release management

ASCI

CN-21

NP-030407

N1-031208

03.68

A038

1

R99

A

8.2.0

8.3.0

Correction to definition of Group-ID, Group call area ID and Group Call Reference

ASCI

CN-25

NP-040373

N1-041524

03.68

A039

1

R99

F

8.3.0

8.4.0

Correction on notification for first talker of VGCS call

ASCI

CN-27

NP-050067

N1-050280

03.68

A040

2

R99

F

8.4.0

8.5.0

Correction of the conditions for establishment of a voice group call

ASCI

03.68

8.5.0

8.5.1

2005-04: Missing SDL files added to zip

CP-28

CP-050057

C1-050786

03.68

A042

2

R99

F

8.5.1

8.6.0

Correction on the use of calling subscriber and destination subscriber

ASCI