4.7 Interaction with supplementary services

23.0783GPPCustomised Applications for Mobile network Enhanced Logic (CAMEL) Phase 4Release 17Stage 2TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

When the gsmSCF initiates a call to a subscriber, the gsmSCF can indicate to the HLR the MT supplementary services that shall be suppressed for this call.

4.7.1 Line identification

For a call subject to CAMEL control, the gsmSCF shall have the option to send the Calling Party Restriction Indicator to the gsmSSF. This information element will be sent to the MSC and shall indicate whether the CLI Presentation Indicator present in the Calling Party Number shall be set by CAMEL action to Restricted.

4.7.2 Call forwarding services

4.7.2.1 Registration of Call Forwarding

The functional behaviour for the registration of the Call Forwarding supplementary service is defined in 3GPP TS 23.082 [20]. The procedure specific to CAMEL is defined in this subclause:

– CAMEL_Check_CF_Interaction.

Figure 4.120-1: Procedure CAMEL_Check_CF_Interaction (sheet 1)

4.7.2.2 Invocation of Call Forwarding

The functional behaviour for the invocation of the Call Forwarding supplementary service is defined in 3GPP TS 23.018 [12] and 3GPP TS 23.082 [20]. The following additional requirements apply.

When Call Forwarding is invoked for a CAMEL subscriber with O‑CSI, the gsmSSF shall send the FTN to the gsmSCF in the format in which it was received from the HLR. When Call Forwarding is invoked for a CAMEL subscriber with D‑CSI or if an N‑CSI is present in the forwarding MSC, then the FTN shall be treated as defined in subclause 4.2.1.2.2.

If the Service Interaction Indicators Two parameter was included in the Initial Address Message, the Continue With Argument information flow or the Connect message, the appropriate indicator shall be applied for the forwarded call.

An HLR shall not send an FTN which is not in international format to a GMSC which does not support CAMEL phase 2, i.e. if the HLR is handling a request from a GMSC for routeing information and the forwarded-to number is registered in a format other than international, the service logic in the HLR shall behave as if the call forwarding is provisioned but not registered.

4.7.2.3 Invocation of Call Deflection

The functional behaviour for the invocation of the Call Deflection supplementary service is defined in 3GPP TS 23.018 [12] and 3GPP TS 23.072 [16]. The following additional requirements apply.

When Call Deflection is invoked by a CAMEL subscriber with O‑CSI, the gsmSSF shall send the DTN to the gsmSCF in the format in which it was received from the MS. When Call Deflection is invoked by a CAMEL subscriber with D‑CSI or if a N‑CSI is present in the VMSC, then the DTN shall be treated as defined in subclause 4.2.1.2.2.

If the Service Interaction Indicators Two parameter was included in the Initial Address Message, the Continue With Argument information flow or the Connect information flow, the appropriate indicator shall be applied for the deflected call.

4.7.3 Call Barring services

When a CAMEL subscriber with O‑CSI and TIF‑CSI attempts to activate a conditional call barring service (BOIC,BOIC-exHC), the HLR shall not check the interactions with call forwarding.

When the gsmSCF initiates a call to a subscriber, the gsmSCF can indicate to the HLR that incoming call barrings shall be suppressed for this call.

When the gsmSCF creates an additional call leg in an existing call, the gsmSCF can indicate to the VLR (via the gsmSSF and MSC) that outgoing call barrings shall be suppressed for this call leg.

4.7.4 Closed User Group

For a CUG subscriber with CAMEL services:

– The HLR shall store (and transfer to the VLR) the necessary subscriber data to ensure that the served subscriber is not unnecessarily prevented by CUG constraints from originating calls.

– The HLR shall store the necessary subscriber data to ensure that the served subscriber is not unnecessarily prevented by CUG constraints from receiving calls.

For an MO, MF or TO call, the CUG information for that call shall be sent to the gsmSCF in the Initial DP information flow.

If the gsmSCF returns a Continue information flow, the call shall continue with the original CUG information unchanged.

If the gsmSCF returns a Connect or Continue With Argument information flow, the CUG handling in table 4.7 applies.

Table 4.7: CUG handling on receipt of Connect or Continue With Argument for an MO, MF or TO call

CUG parameters in information flow	Handling
Non-CUG call (note 1)	Remove CUG information for the call and continue as a non-CUG call
CUG information (note 2)	Call shall continue with modified CUG information
No CUG information	Call shall continue with original CUG information
NOTE 1: Received in Service Interaction Indicators Two IE. NOTE 2: CUG information consists of at least one of CUG Interlock Code and Outgoing Access Indicator.

For an MT call which is to be routed to the terminating subscriber, the CUG information shall be extracted from the Send Routeing Information ack and sent to the gsmSCF in the Initial DP, but the gsmSCF shall not have the ability to change the CUG information for the call.

For an VT call which is to be routed to the terminating subscriber, the CUG information shall be extracted from the incoming ISUP IAM and sent to the gsmSCF in the Initial DP, but the gsmSCF shall not have the ability to change the CUG information for the call.

For an MT or VT call which is subject to CAMEL forwarding, the gsmSCF shall return a Connect information flow and the CUG handling in table 4.7 applies.