Enhanced Coverage Restriction Control

Enhanced Coverage Restriction Control support using SCEF enables 3rd party service providers to query status of, enhanced coverage restriction, or enable/disable enhanced coverage restriction per individual UEs.

The Enhanced Coverage Restriction Control procedure requested by SCS/AS is determined from the URI as described below.

Table 2-6 Supported Enhanced Coverage Restriction Control Resources and Methods

Resource Name	Resource URI	HTTP Method(s)	HTTP Initiator
Query	3gpp-ecr-control/v1/{scsAsId}/query	POST	SCS/AS
Configure	3gpp-ecr-control/v1/{scsAsId}/configure	POST	SCS/AS

1. The SCS/AS sends an Enhanced Coverage Request (External Identifier or the MSISDN, SCS/AS Identifier, Request Type, and Enhanced Coverage Restriction Data) message to SCEF. Request Type indicates if the request needs to query the status, enable, or disable the enhanced coverage restriction. Enhanced Coverage Restriction Data provides data related to the Enhanced Coverage Restriction. Enhanced Coverage Restriction Data is only present if the Request Type enables or disables the enhanced coverage restriction.
2. Based on operator policies, if the SCS/AS is not authorized to perform this request, or the Enhanced Coverage Request is malformed, or the SCS/AS has exceeded its quota or rate of submitting Enhanced Coverage requests, SCEF performs step 9 and provides a Cause value appropriately indicating the failure result.
3. SCEF sends an Enhanced Coverage Request (External Identifier or MSISDN Type) message to the HSS.
4. HSS examines the Enhanced Coverage Request message for the existence of an External Identifier or MSISDN, any included parameters in the acceptable range for the operator, and the Enhanced Coverage restriction by the serving MME/SGSN. If this check fails, the HSS follows step 8 and provides a Cause value indicating the reason for the failure condition to the SCEF.

   If the Request Type is to get the current status of enhanced coverage, HSS retrieves the value and follows the procedure at step 8; otherwise, if the Type is to enable or to disable the enhanced coverage, HSS sets the Enhanced Coverage Restricted parameter to the appropriate value and the procedure continues with step 5.

5. If required by the specific Enhanced Coverage Request Type and when Enhanced Coverage is supported by the serving MME/SGSN, HSS sends an Insert Subscriber Data Request (Type) message to the MME/SGSN.
6. Based on operator policies, MME/SGSN may reject the request (for example, for an overload or HSS has exceeded its quota or rate of submitting enhanced coverage requests defined by an SLA).

   The MME/SGSN updates Enhanced Coverage Restricted parameters in the MME/SGSN context.

   The MME/SGSN transfers the Enhanced Coverage Restricted parameters stored as part of its context information during the MME/SGSN change.

   Note:

   UE is informed of the updated Enhanced Coverage Restricted parameters value at the next TAU/RAU or, based on the local policy, the network can detach the UE indicating re-attach is required.
7. If the Enhanced Coverage restriction is updated successfully, the MME/SGSN sends an Insert Subscriber Data Answer (Cause) message to HSS. MME/SGSN may include the Enhanced Coverage Restricted parameter in the Insert Subscriber Data Answer message.
8. HSS sends an Enhanced Coverage Response (Cause) message to SCEF. HSS includes result = success/failure and in case of success may include Enhanced Coverage Restriction Data.
9. SCEF sends an Enhanced Coverage Response (Cause, Enhanced Coverage Restriction Data) message to the SCS/AS. Cause indicates success or failure. If, in step 1, the Enhanced Coverage Request message is sent to query the status of Enhanced Coverage Restricted, then the Enhanced Coverage Restriction Data is included (in case of success) in the Enhanced Coverage Response message.