13.15 Multicall

23.2053GPPBearer-independent circuit-switched core networkRelease 17Stage 2TS

The procedures specified in 3GPP TS 23.135 [17] for the Multicall supplementary service shall be followed. The following clauses describe the additional requirements for the bearer independent CS core network. If out-of-band transcoder control is applied for a speech call, it shall be performed in accordance with 3GPP TS 23.153 [3].

13.15.1 Mobile Originating

When the UE is in active mode and it makes a request for the multicall function on a new traffic channel, call and bearer establishment shall be as described for mobile originating call.

When the UE is in active mode and it makes a request for the multicall function using an existing traffic channel, call and bearer establishment shall be as described for call hold function. An active call will be placed on hold and the additional originating call will be initiated.

13.15.2 Mobile Terminating

When the UE is in active mode and it makes a request for the multicall function on a new traffic channel, call and bearer establishment shall be as described for mobile terminating call. Access bearer assignment shall occur either after a Call Confirmed or a Connect message is received from the UE.

When the UE is in active mode and it makes a request for the multicall function using an existing traffic channel, call and bearer establishment shall be as described for call hold function. An active call will be placed on hold and the additional terminating call will be initiated.