6 Interaction with other supplementary services

03.873GPPStage 2TSUser-to-User Signalling (UUS)

GSM 02.87 specifies interaction of UUS with other supplementary services. Additional details are provided in this clause.

6.1 Call forwarding unconditional (CFU)

No impact.

6.2 Call forwarding on mobile subscriber busy (CFB)

No impact, if CFB is invoked due to a NDUB condition or due to UDUB before an alerting message was received from the mobile station.

If CFB is invoked due to a UDUB indication from the B forwarding subscriber the same interaction as for CFNRy shall apply.

6.3 Call forwarding on no reply (CFNRy)

If UUS Service 1 is implicitly requested for a call to a subscriber who has Call Forwarding on no reply active and operative, the forwarding MSC shall store the UUI. If CFNRy is invoked, the stored UUI shall be forwarded with the call.

If UUS Service 1 is explicitly requested as not required for a call to a subscriber who has Call Forwarding on no reply active and operative, the forwarding MSC shall store UUS 1 service request and UUI, if any. If the forwarding user accepts the UUS1 supplementary service request in the Alerting message, the CFNRy supplementary service can be invoked and the stored UUS1 service request and UUI, if any, shall be forwarded with the call. If the forwarding user rejects the UUS1 supplementary service request or does not include a response related to it in the Alerting message, then the CFNRy supplementary service can be invoked but the UUS1 service request and UUI, if any, shall not be forwarded with the call.

If UUS Service 1 is explicitly requested as required for a call to a subscriber who has Call Forwarding on no reply active and operative and the no reply condition timer expires, the remote MSC shall release the call towards the calling subscriber.

If Call Forwarding on no reply is invoked for a call for which UUS Service 2 was requested as not required, UUS Service 2 shall not be requested for the forwarding leg, i.e. UUS 2 is no longer available for the call.

Call Forwarding on no reply shall not be invoked if UUS Service 2 was requested required for the initial mobile terminated call.

If UUS Service 3 is requested for a call to a subscriber who has Call Forwarding on no reply active and operative, the forwarding MSC shall store the UUS3 request. If CFNRy is invoked the UUS3 request shall be forwarded with the call.

For further details refer to procedures UUS_ICH_Check_Forwarding and UUS_MSC_Clear_UUS.

6.4 Call forwarding on mobile subscriber not reachable (CFNRc)

No impact.

6.5 Call waiting (CW)

No impact.

6.6 Call hold (HOLD)

No impact.

6.7 Completion of calls to busy subscribers (CCBS)

Requests for the activation of the UUS supplementary service contained in the original call request shall be maintained along with other call information used for the CCBS supplementary service.

The network shall also store any UUI containing in the original call request and use this stored UUI in the CCBS call.

6.8 Explicit call transfer (ECT)

When calls are transferred as a result of invocation of explicit call transfer supplementary service, the UUS supplementary service activated on either of the calls prior to the invocation of the explicit call transfer supplementary service shall be cancelled by the network.

No specific notification shall be sent to the users on the resulting call when the UUS supplementary service is no longer activated.

The users on the resulting call can request service 3 again, if required.

6.9 Multi party service (MPTY)

No impact.

6.10 Advice of charge (AoC)

No impact.

6.11 Barring of outgoing calls (BAOC)

No impact.

6.12 Barring of outgoing international calls (BOIC)

No impact.

6.13 Barring of outgoing international calls except those directed to the home PLMN country (BOIC-exHC)

No impact.

6.14 Barring of incoming calls (BAIC)

No impact.

6.15 Barring of incoming calls when roaming outside the home PLMN country (BIC-Roam)

No impact.

6.16 Call deflection (CD)

If Call Deflection is invoked before alerting there is no impact.

If Call Deflection is invoked after alerting the same interactions as for Call forwarding on no reply shall apply.