The subclause 10.3.3.2 and subclause 10.3.3.3 describe the group call setup between the MCPTT system and the LMR system on an interworking group defined in the MCPTT system. The subclause 10.3.3.4 and subclause 10.3.3.5 describe the group call setup between the MCPTT system and the LMR system on an interworking group defined in the LMR system. The subclause 10.3.3.7 describes the late entry procedures and subclause 10.3.3.8 describes the group call release procedures. Group calls can use MC media encryption between the IWF and the MCPTT clients as described in TS 33.180. A call that uses an LMR vocoder may use LMR E2EE if the calling and called parties have previously been provisioned with the appropriate LMR E2EE keys.
The procedures in the present subclause are applicable to the following non-broadcast group call types: pre-configured group regroup calls, pre-configured user regroup calls and group regroup calls.
In this procedure, an MCPTT user is initiating a group call on an interworking group defined in the MCPTT system. The signalling procedure is described in Figure 10.3.3.2-1.
This subclause is based upon subclause for pre-arranged group call setup in subclause 10.6.2.3.1.1.2 of TS 23.379.
Pre-conditions:
The interworking group information is known at the MCPTT server and the IWF by configuration or group creation. The interworking group has been defined in the MCPTT system.
MCPTT client 1 and MCPTT client 2 are registered and their respective users are authenticated and authorized to use the MCPTT service.
The users in this interworking group have been affiliated to the group.
The mapping relationship of group and user identities between the MCPTT system and the LMR system has been configured at the IWF.
MCPTT server sends IWF group call request(s) towards the IWF. If the IWF has affiliated to this group on behalf of the group's LMR users, only one IWF group call request message is sent to the IWF. If the MCPTT server has received individual affiliations from the group's LMR users, an individual IWF group call request is sent (to the IWF) for each affiliated LMR user.
The IWF returns IWF group call response(s) to the MCPTT server. If E2EE is specified, then the MCPTT users and the LMR users shall use the same codec. If E2EE is not specified, the MCPTT users and the LMR users can use different codecs and transcoding is needed at the IWF.
The group call on the interworking group has successfully established media plane for communication and any user can transmit media. The MCPTT system where the interworking group is defined is the controlling system of the group call and manages the floor control.
In this procedure, an LMR user is initiating a group call on an interworking group defined in the MCPTT system. The signalling procedure is described in Figure 10.3.3.3-1.
This subclause is based upon subclause for pre-arranged group call setup in subclause 10.6.2.3.1.1.2 of TS 23.379.
Pre-conditions:
The interworking group information is known at the MCPTT server and the IWF by configuration or group creation. The interworking group has been defined in MCPTT system.
MCPTT client 1 and MCPTT client 2 are registered and their respective users are authenticated and authorized to use the MCPTT service.
The users in this interworking group have been affiliated to the interworking group.
The mapping relationship of group and user identities between the MCPTT system and the LMR system has been configured at the IWF.
The IWF sends an IWF group call request to the MCPTT server for call establishment. If floor control is requested by the calling LMR user, an indication of implicit floor request is included. If the group call request contains an implicit floor request it may also include location information.
MCPTT server calls the affiliated users from MCPTT system as described in TS 23.379. If E2EE is specified, then the MCPTT users and the LMR users shall use the same codec. If E2EE is not specified, the MCPTT users and the LMR users can use different codecs and transcoding is needed at the IWF.
If the group has other affiliated LMR users than the calling party and the MCPTT server has received individual affiliations from those LMR users, an individual IWF group call request is sent to the IWF for each affiliated LMR user.
The interworking group call has successfully established media plane for communication and any user can transmit media. The MCPTT system where the interworking group is defined is the controlling system of the group call and manages the floor control.
In this procedure, an MCPTT user is initiating a group call on an interworking group defined in the LMR system. The signalling procedure is described in Figure 10.3.3.4-1.
This subclause is based upon subclause for Pre-arranged group call setup in subclause 10.6.2.3.1.1.2 of TS 23.379.
Pre-conditions:
The interworking group information is known at the MCPTT Server and the IWF by configuration or group creation. The interworking group has been defined in the LMR system.
MCPTT client 1 and MCPTT client 2 are registered and their respective users are authenticated and authorized to use the MCPTT service.
The users in this interworking group have been affiliated to the group.
The mapping relationship of group and user identities between the MCPTT system and the LMR system has been configured at the IWF.
The IWF sends individual IWF group call request(s) to the MCPTT server for each affiliated MCPTT user in the group, in this example scenario to the user in MCPTT client 2.
The MCPTT server sends a group call response to the initiating MCPTT user. If E2EE is specified, then the MCPTT users and the LMR users shall use the same codec. If E2EE is not specified, the MCPTT users and the LMR users can use different codecs and transcoding is needed at the IWF.
The group call over the interworking group has successfully established media plane for communication and any user can transmit media. The LMR system where the interworking group is defined is the controlling system of the group call and manages the floor control.
In this procedure, an LMR user is initiating a group call on an interworking group defined in the LMR system. The signalling procedure is described in Figure 10.3.3.5-1.
This subclause is based upon subclause for Pre-arranged group call setup in subclause 10.6.2.3.1.1.2 of TS 23.379.
Pre-conditions:
The interworking group information is known at the MCPTT Server and the IWF by configuration or group creation. The interworking group has been defined in the LMR system.
MCPTT client 1 and MCPTT client 2 are registered and their respective users are authenticated and authorized to use the MCPTT service.
The users in this interworking group have been affiliated to the group.
The mapping relationship of group and user identities between the MCPTT system and the LMR system has been configured at the IWF.
The IWF sends an IWF group call request(s) to the MCPTT server for call establishment. An individual IWF group call request is sent to the MCPTT server for each affiliated MCPTT user in the group, in this example scenario to the users in MCPTT clients 1 and 2. If floor control is requested by the calling LMR user, an indication of implicit floor request is included. If the group call request contains an implicit floor request it may also include location information.
The MCPTT server acknowledges the IWF group call request(s) by sending a IWF group call response(s) to the IWF. If E2EE is specified, then the MCPTT users and the LMR users shall use the same codec. If E2EE is not specified, the MCPTT users and the LMR users can use different codecs and transcoding is needed at the IWF.
The interworking group call has successfully established media plane for communication and any user can transmit media. The LMR system where the interworking group is defined is the controlling system of the group call and manages the floor control.
The MCPTT client encodes audio using a codec defined for the MCPTT group, encrypts the encoded voice using procedures in TS 33.180, and forwards the encrypted voice media to the MCPTT server.
The IWF decrypts the voice media from the MCPTT client using the procedures in TS 33.180. The IWF transcodes the voice to a LMR codec. If needed, the IWF re-encrypts the transcoded voice media using LMR security procedures (these are out-of-scope of this specification), and forwards the voice media to the LMR system.
The IWF receives voice media from the LMR system. If the voice media is encrypted, the IWF decrypts the voice media using LMR security procedures (these are out-of-scope of this specification). The IWF transcodes the voice to the group's MCPTT codec. The IWF re-encrypts the transcoded voice using the procedures in TS 33.180.