10.5.6 Floor control on an interworking group homed in the MCPTT system

23.2833GPPMission Critical Communication Interworking with Land Mobile Radio SystemsRelease 18TS

Figure 10.5.6‑1 shows the procedure for floor control on an interworking group homed in the MCPTT system, and the LMR system is configured for local floor control request filtering. Simultaneous floor requests are included to show various aspects of interworking floor control.

Pre-conditions:

1. The interworking group is homed in the MCPTT system.

2. The interworking group is previously defined on the group management server.

3. MCPTT client 1, MCPTT client 2, and LMR users (represented by the IWF) are affiliated to that group.

4. An interworking group call is ongoing involving MCPTT users and LMR users (represented by the IWF). The floor is currently idle.

Figure 10.5.6-1: Floor control on a group homed in the MCPTT system

1. The user of MCPTT Client 1 wants to send voice media over the session. At the same time a user in the LMR system (represented by the IWF) wants to also send voice media over the session.

2. MCPTT Client 1 sends a floor request message to the MCPTT floor control server.

3. The IWF sends a floor request message to the MCPTT floor control server.

NOTE: If multiple LMR users want to speak, it is assumed that the LMR system has arbitrated these requests based on local policies and only presents one floor request to the MCPTT system.

4. Since the group is homed in the MCPTT system the MCPTT floor control server performs final floor control determination. In this case the MCPTT floor control server determines to accept the floor request from MCPTT Client 1 based on local policy and arbitration results (e.g., according to time of arrival of the request versus the competing request from the IWF).

5. The IWF is notified that its floor request was rejected.

6. The MCPTT floor control server sends a floor granted message to MCPTT client 1.

7. The MCPTT floor control server sends a floor taken message to both MCPTT client 2 and the IWF to inform them of who is granted the floor.

8. MCPTT Client 1 notifies the user that he/she has been granted the floor and may begin speaking.

9. MCPTT Client 1 begins sending voice media over the established session. The media is distributed to affiliated group members including the IWF.