6.15 Procedures for GNSS assistance data Collection

23.2733GPP5G System (5GS) Location Services (LCS)Release 18Stage 2TS

6.15.1 GNSS assistance data collection from untrusted AF via NEF

The following procedure is used by LMF to collect GNSS assistance information from AFs via the NEF.

Figure 6.15.1-1: GNSS assistance data collection from untrusted AF

1a-1c. Reuse the steps 1a-1c in figure 6.2.2.3-1 of TS 23.288 [37] with following difference:

– The AF should also provide its serving area to NEF. NEF should map the serving area into TA(s) if it is presented as geographical location and update the NEF profile in NRF including the serving area information.

1d-1e. Reuse the steps 1d-1e in figure 6.2.2.3-1 of TS 23.288 [37] with following difference:

– When LMF needs to discovery the available data from AFs and the appropriated NEF to collect GNSS assistance data, LMF additionally provides TAs in the Nnrf_NFDiscovery_Request_request service operation.

2-5. Reuse the steps 2-5 in figure 6.2.2.3-1 of TS 23.288 [37] with following difference:

– Besides available GNSS assistance data, AF also provides associated serving area of the GNSS assistance data and optional precise global coordinates of the source of the GNSS assistance data. NEF may map the serving area into a TA or TA list.

6. After LMF gets the GNSS assistance data, it can send the assistance data to UE via the procedures described in clauses 6.14 or 6.11.1 during a positioning session.

6.15.2 GNSS assistance data collection from trusted AF

For trusted AFs, LMF collects GNSS assistance data through AFs directly. LMF discovers trusted AFs covering LMF serving area through NRF and subscribes to GNSS assistance data exposure from discovered trusted AFs.

Figure 6.15.2-1: GNSS assistance data collection from trusted AF

1a-1c. AF invokes Nnrf_NFManagement_NFUpdate_request service operation to register its GNSS related information including Event IDs, and associated AF identification, Application ID(s) and its serving area (TAs). NRF stores the received AF update information and sends Nnrf_NFManagement_NFUpdate_response message to AF.

1d-1e. When LMF needs to discovery the available GNSS assistance data from AFs, LMF provide TAs to NRF through Nnrf_NFDiscovery service to discover related AFs.

2. LMF subscribes to or cancels subscription to GNSS assistance data in AF by invoking the Naf_EventExposure_Subscribe/Naf_EventExposure_Unsubscribe service operation.

3. AF notifies the LMF with the available GNSS assistance data by invoking Naf_EventExposure_Notify service operation. AF also provides associated serving area (TAs) of the GNSS assistance data and optional precise global coordinates of the source of the GNSS assistance data. The AF notifies the LMF with the data by invoking Nnef_EventExposure_Notify service operation.

4. After LMF gets the GNSS assistance data, it can send the data to UE via the procedures described in clauses 6.14 or 6.11.1 during a positioning session.