Content for  TS 23.283  Word version:  19.0.0

Floor control for interworking applies to both private call and group call. Floor control involving a single MCPTT server is described in TS 23.379. Floor control involving multiple MCPTT servers is also described in TS 23.379 in that a primary MCPTT server is interconnected to a partner MCPTT server. Subclause 10.5.2 describes information flows for floor control between an MCPTT server and an IWF, and are based on those defined interconnection in TS 23.379. Subclause 10.5.3 describes aspects of floor control that apply to interworking groups and interworking private calls. Subclauses 10.5.4 / 10.5.6 and 10.5.5 / 10.5.7 describe general cases of floor control on an interworking group defined in the LMR system and in the MCPTT system respectively, where the partner system has been configured to apply/not apply local filtering of floor control requests before communicating with the primary system. Subclauses 10.5.9 and 10.5.10 describe general cases of floor control in a private call, where the controlling role is taken by the LMR system and the MCPTT system respectively.

Subclause 10.9.1.4.1 of TS 23.379 describes floor control involving groups in multiple MCPTT systems where floor control arbitration resides with the primary MCPTT server and all floor control messages are routed to that primary MCPTT server. The group is homed on the primary MCPTT server. An interworking group can be homed on the MCPTT server or on the LMR system. When the group is homed on the MCPTT server the floor control server is on this MCPTT server. When the group is homed on the LMR system the floor control server is represented by the IWF. The primary MCPTT system of an MCPTT group is defined by configuration and identified by the MC service group ID. Subclause 10.9.1.4.2 of TS 23.379 describes floor control involving groups in multiple MCPTT systems where the partner MCPTT system filters its MCPTT users' floor requests before communicating with the floor control server of the primary MCPTT system. When an MCPTT system is interworking with an IWF, depending on where the group is homed the MCPTT server, or the IWF can filter floor control requests in the same way as an interconnected MCPTT system. In a private call, one of the IWF or MCPTT server acts as the controlling floor control server within the call, and manages arbitration of floor control requests received from both users in the call. The entity (MCPTT server or IWF) that does not fulfil the controlling role shall send all floor control requests from its served call participant to the controlling floor control server without filtering.

This procedure describes the case where a transmitting radio cannot be signalled that the floor has been taken or revoked. Within the context of interworking between MCPTT and LMR systems, this condition can occur due to both MCPTT and LMR users obtaining the floor simultaneously, or the floor granted to an LMR user is taken by an MCPTT user. Figure 10.5.4-1 shows the high-level procedure where an MCPTT session is already established between the floor participants (with floor granted to an LMR user represented by the IWF) and the floor control server (with an override based on priority and configured to permit the transmission of overridden floor participant from the IWF). The group is defined in the MCPTT system and the MCPTT Server is the floor control server. Only two UEs involved in the session are shown for simplicity. Pre-conditions:

1. The MCPTT floor control server has been configured to support override.
2. The override supported in this case permits both the overridden floor participant and the overriding floor participant to be transmitting.
3. An MCPTT session is established between an MCPTT client, the interworked system, and MCPTT server.
4. Session is ongoing.

Figure 10.5.5-1 shows the procedure for floor control on an interworking group homed in the LMR system. Simultaneous floor requests are included to show various aspects of interworking floor control. Pre-conditions:

1. The interworking group is homed in the LMR system.
2. The MCPTT server is configured to locally filter competing floor control requests before communicating with the IWF.
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 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 10.5.7-1 shows the procedure for floor control on an interworking group defined in the LMR system where local filtering is not performed by the MCPTT server. Simultaneous floor requests are included to show various aspects of interworking floor control. Pre-conditions:

1. The interworking group is defined in the LMR system.
2. The MCPTT system is configured to send competing floor control requests to the LMR system (represented by the IWF) for floor control arbitration.
3. MCPTT client 1, MCPTT client 2, and LMR users are affiliated to that group.
4. An interworking group call is ongoing involving MCPTT users and LMR users. The floor is currently idle.

Figure 10.5.8-1 shows the procedure for floor control on an interworking group defined in the MCPTT system where local filtering is not performed by the LMR system. Simultaneous floor requests are included to show various aspects of interworking floor control. Pre-conditions:

1. The interworking group is defined in the MCPTT system.
2. MCPTT client 1, MCPTT client 2, and LMR users are affiliated to that group.
3. The LMR system (represented by the IWF) is configured to send all competing floor control requests to the MCPTT system for floor control arbitration.
4. The IWF is not affiliating on behalf of LMR users. All LMR group affiliations are passed through the IWF to the MCPTT server.
5. An interworking group call is ongoing involving MCPTT users and LMR users. The floor is currently idle.

Figure 10.5.9-1 shows a procedure for a private call with floor control where the LMR system controls the floor. A request for transmission by the MCPTT user while the LMR user has the floor is rejected by the IWF, to show various aspects of interworking floor control. Pre-conditions:

1. A private call has been set up between an LMR user and MCPTT client 1.
2. The LMR system is controlling the floor, via the IWF.
3. MCPTT client 1 has the floor.

Figure 10.5.10-1 shows a procedure for a private call with floor control where the MCPTT system controls the floor. A request for transmission by the LMR user while the MCPTT user has the floor is accepted by the MCPTT server, to show various aspects of interworking floor control. Pre-conditions:

1. A private call has been set up between the LMR user and MCPTT client 1.
2. The MCPTT server is controlling the floor.
3. The floor is idle.