5.3.2A Overall procedure for ProSe Direct Discovery (Model B)

23.3033GPPProximity-based services (ProSe)Release 17Stage 2TS

Figure 5.3.2A-1: Overall procedure for ProSe Direct Discovery (Model B)

This procedure is applied for restricted ProSe Direct Discovery when the ProSe enabled UE is served by E-UTRAN.

1. Service authorisation for ProSe direct services is performed for ProSe Direct Discovery as defined in clauses 5.2 and 4.5.1.

If the UE is authorised to perform restricted ProSe Direct Discovery, Model B, as a Discoveree UE, the following steps take place:

2a. When the UE is triggered to perform restricted ProSe Direct Discovery, Model B, it sends a discovery request to the ProSe Function in the HPLMN to obtain a ProSe Response Code as defined in clauses 5.3.3A.2 and 5.3.3A.3 The ProSe Function further interacts with ProSe Application Server for the authorization of the discovery request.

3a. If the request is successful and the UE is provided with a ProSe Response Code and an associated Discovery Query Filter(s), then the UE starts monitoring for the ProSe Query Code on PC5 interface.

4a. If a received ProSe Query Code matches any of the Discovery Query Filter(s), the UE announces the associated ProSe Response Code on the PC5 interface.

NOTE 1: More details on the Access Stratum protocol of this step are provided in RAN specifications.

If the UE is authorised to perform restricted ProSe Direct Discovery, Model B, as a Discoverer UE, the following steps take place:

2b. When the UE is triggered to perform restricted ProSe Direct Discovery, Model B, it sends a discovery request to the ProSe Function in the HPLMN for a ProSe Query Code as defined in clauses 5.3.3A.4 and 5.3.3A.5. The ProSe Function further interacts with ProSe Application Server for the authorization of the discovery request.

3b. If the request is successful and the UE is provided with a ProSe Query Code and the Discovery Response Filter(s) consisting of ProSe Response Code(s) and ProSe Application Mask(s), the UE announces the ProSe Query Code on the PC5 interface.

4b. The UE starts to monitor on PC5 interface for any ProSe Response Code(s) that might match the Discovery Response Filter(s).

NOTE 2: More details on the Access Stratum protocol of this step are provided in RAN specifications.

5b. When the UE detects a match for one or more ProSe Response Code(s), it reports the ProSe Response Code to the ProSe Function as defined in clauses 5.3.4A.1 and 5.3.4A.2.

Non roaming direct discovery procedures cover the case where both the Discoveree UE and Discoverer UE are served by their respective HPLMN. Roaming direct discovery procedures cover the other cases.