Content for  TS 38.305  Word version:  18.0.0

The AMF serving UE1 sends a location request to the LMF including information on the required location results of the n UEs (e.g., absolute location, relative location or ranges and directions between pairs of UE(s)), the required LCS QoS and the Application layer IDs of the UEs when available, as described in TS 23.273.

The LMF sends an SL-MT-LR request to UE1 (via serving AMF) including the types of required location results (e.g., absolute location, relative locations or distances and/or directions) and the Application layer IDs of the other UEs 2 to n.

UE1 attempts to discover the other UEs 2 to n using their Application layer IDs if not already discovered, as described in TS 23.273.

UE1 obtains the sidelink positioning capabilities of the discovered UEs using the SLPP capability transfer procedures specified in clause 7.11.2.1.

UE1 returns a SL-MT-LR Response to the LMF (via serving AMF) indicating which of the UEs 2 to n have been discovered and the sidelink positioning capabilities of the discovered UEs, if obtained.

The LMF may request the sidelink positioning capabilities of the UEs 1 to n from UE1 if not already received at step 5 using the Supplementary RSPP Capability Transfer procedure. The Supplementary RSPP Capability Transfer messages include embedded SLPP Capability Transfer messages for UEs 1 to n together with their Application Layer IDs. UE1 may instigate the procedure for step 6b and returns the obtained capabilities of the UEs to the LMF using the Supplementary RSPP Capability Transfer procedure which includes embedded SLPP Capability Transfer messages for UEs 1 to n together with their Application Layer IDs.

UE1 may instigate the SLPP Capability Transfer procedure specified in clause 7.11.2.1 with UEs 2 to n to obtain the sidelink positioning capabilities for UEs 2 to n, if not already obtained (e.g., at step 4).

UE1 may send a request for specific sidelink assistance data to the LMF using the Supplementary RSPP Assistance Data Transfer procedure. The Supplementary RSPP Assistance Data Transfer messages include embedded SLPP Request Assistance Data messages for UEs 1 to n together with their Application Layer IDs. The LMF determines the sidelink assistance data, possibly taking the received UE capabilities from step 4 or 6a into account and provides the assistance data to UE1 using the Supplementary RSPP Assistance Data Transfer procedure which includes embedded SLPP Assistance Data Transfer messages for UEs 1 to n together with their Application Layer IDs.

UE1 may instigate the SLPP Assistance Data Transfer procedure specified in clause 7.11.2.2 with UEs 2 to n to provide the received assistance data from step 7a to the UEs 2 to n. The assistance data may assist UEs 1 to n to obtain sidelink location measurements and/or may assist UE1 to calculate sidelink positioning/ranging location results.

The LMF sends a request for sidelink location information to UE1 using the Supplementary RSPP Location Information Transfer procedure. The Supplementary RSPP Location Information Transfer messages include embedded SLPP Location Information Transfer messages for UEs 1 to n together with their Application Layer IDs. The request may include an indication whether location calculation should be performed by the UEs (Target UE-based), or whether location measurements should be provided for location calculation at the LMF (Target UE-assisted). UE1 may instigate the procedure for step 8b and provides the sidelink location measurements or location estimates to the LMF using the Supplementary RSPP Location Information Transfer procedure which includes embedded SLPP Location Information Transfer messages for UEs 1 to n together with their Application Layer IDs.

UE1 instigates the SLPP Location Information Transfer procedure specified in clause 7.11.2.3 among UEs 1 to n in which UE1 to n obtain sidelink location measurements and UEs 2 to n transfer their sidelink location measurements to UE1.

The LMF returns a location response to the AMF with any sidelink positioning/ranging location results obtained as a result of steps 6 to 8.

The AMF serving UE1 sends a location request to the LMF to request periodic or triggered sidelink positioning/ranging location results of the n UEs (e.g., absolute locations, relative location or ranges and directions between pairs of UE(s)). The request includes information on the time interval between successive location reports, the total number of reports, and/or the details of the trigger event (e.g., change of location or ranges), the SUPI of UE1, the required LCS QoS and the Application layer IDs of the UEs when available, as described in TS 23.273.

The LMF sends a Periodic-Triggered SL-MT-LR request to UE1 (via serving AMF) including the information of the periodic or triggered event, the types of required location results (e.g., absolute location, relative locations or distances and/or directions) and the Application layer IDs of the other UEs 2 to n.

UE1 attempts to discover the other UEs 2 to n using their Application layer IDs if not already discovered, as described in TS 23.273.

UE1 obtains the sidelink positioning capabilities of the discovered UEs using the SLPP capability transfer procedures specified in clause 7.11.2.1.

UE1 returns a Periodic-Triggered SL-MT-LR Response to the LMF (via serving AMF) indicating which of the UEs 2 to n have been discovered, whether the UEs 1 to n accept the periodic or triggered location request, and the sidelink positioning capabilities of the discovered UEs, if obtained.

The LMF may instigate one or more SLPP procedures with UE1 to transfer sidelink positioning capabilities for UEs 1 to n, to transfer SLPP assistance data to UE1, and to transfer sidelink location information for UEs 1 to n (e.g., sidelink ranging and/or location measurements or location estimates obtained at step 6b), as described in steps 6 - 8 in Figure 7.3A.2-1. The UE1 may also instigate one or more SLPP procedures with the LMF after the first SLPP message has been received from the LMF (e.g., to request sidelink assistance data from the LMF).

UE1 may instigate one or more SLPP procedures among UEs 1 to n to transfer sidelink positioning capabilities, provide sidelink assistance data to the UEs 2 to n, and/or obtain sidelink location information for UEs 1 to n (e.g., sidelink ranging and/or location measurements or location estimates) as described in steps 6 - 8 in Figure 7.3A.2-1. If UE1 received a SLPP request for sidelink location information at Step 6a, UE1 sends a SLPP response to the LMF and includes the location results obtained at Step 6b.

The LMF returns a location response to the AMF indicating that the SL-MT-LR for periodic, triggered Location Events has been successfully initiated and with any initial sidelink positioning/ranging location results obtained as a result of steps 6.

The UEs 1 to n may periodically perform sidelink positioning/ranging in order to support steps 9 and 10. The UE may perform steps 6b, 7b, and 8b in Figure 7.3A.2-1.

The UE monitors for occurrence of the trigger or periodic event requested at step 2.

UE1 sends an event report message to the LMF (via serving AMF) indicating the type of event being reported and may include sidelink location results obtained at step 8.

The LMF (via serving AMF) returns an event report acknowledgement to UE1.

If sidelink location results are needed for event reporting and not received at step 10, the LMF may instigate one or more SLPP procedures with UE1 as described in step 6a/6b.

The LMF returns the event report and any sidelink location results to the LCS Client or AF.

The UEs 1 to n continue to periodically perform sidelink positioning/ranging as in step 8.

The UE1 continues to monitor for further periodic or trigger events as in step 9 and instigates steps 10-12 each time a periodic or trigger event is detected.

Based on a trigger of service request (e.g., received from the application layer in UE1) UE1 discovers the other UEs 2 to n, as described in TS 23.273.

UE1 may obtain the sidelink positioning capabilities of the discovered UEs using the SLPP capability transfer procedures specified in clause 7.11.2.1.

UE1 sends an SL-MO-LR Request to the LMF via the serving AMF, including the Application layer IDs of the other UEs 2 to n together with an indication on any sidelink assistance data needed, position calculation assistance from the LMF needed, and/or whether location results should be transferred to an LCS client or AF. For position calculation assistance from the LMF, the SL-MO-LR Request may include information on the type of sidelink positioning/ranging location results (e.g., absolute location, relative location or distances and directions between pairs of UEs) and desired QoS.

The LMF may request the sidelink positioning capabilities of the UEs 1 to n from UE1 if not already received at step 3 using the Supplementary RSPP Capability Transfer procedure. The Supplementary RSPP Capability Transfer messages include embedded SLPP Capability Transfer messages for UEs 1 to n together with their Application Layer IDs. UE1 may instigate the procedure for step 4b and returns the obtained capabilities of the UEs to the LMF using the Supplementary RSPP Capability Transfer procedure which includes embedded SLPP Capability Transfer messages for UEs 1 to n together with their Application Layer IDs.

UE1 may instigate the SLPP Capability Transfer procedure specified in clause 7.11.2.1 with UEs 2 to n to obtain the sidelink positioning capabilities for UEs 2 to n, if not already obtained (e.g., at step 2).

UE1 may send a request for specific sidelink assistance data to the LMF, if the request was not already included at step 3 using the Supplementary RSPP Assistance Data Transfer procedure. The Supplementary RSPP Assistance Data Transfer messages include embedded SLPP Request Assistance Data messages for UEs 1 to n together with their Application Layer IDs. The LMF determines the sidelink assistance data, possibly taking the received UE capabilities from step 2 or 4a into account and provides the assistance data to UE1 using the Supplementary RSPP Assistance Data Transfer procedure which includes embedded SLPP Assistance Data Transfer messages for UEs 1 to n together with their Application Layer IDs.

UE1 may instigate the SLPP Assistance Data Transfer procedure specified in clause 7.11.2.2 with UEs 2 to n to provide the received assistance data from step 5a to the UEs 2 to n. The assistance data may assist UEs 1 to n to obtain sidelink location measurements and/or may assist UE1 to calculate sidelink positioning/ranging location results.

If UE1 requested position calculation assistance from the LMF or location transfer to an LCS client or AF at step 3, the LMF sends a request for sidelink location information to UE1 using the Supplementary RSPP Location Information Transfer procedure. The Supplementary RSPP Location Information Transfer messages include embedded SLPP Location Information Transfer messages for UEs 1 to n together with their Application Layer IDs. The request may also include an indication whether location calculation should be performed by the UEs (SL Target UE-based), or whether location measurements should be provided for location calculation at the LMF (SL Target UE-assisted). UE1 may instigate the procedure for step 6b and provides the sidelink location measurements or location estimates to the LMF using the Supplementary RSPP Location Information Transfer procedure which includes embedded SLPP Location Information Transfer messages for UEs 1 to n together with their Application Layer IDs.

UE1 instigates the SLPP Location Information Transfer procedure specified in clause 7.11.2.3 among UEs 1 to n in which UE1 to n obtain sidelink location measurements and UEs 2 to n transfer their sidelink location measurements to UE1.

The LMF sends a SL-MO-LR Response to the AMF which forwards the SL-MO-LR Response to UE1. If UE1 requested position calculation assistance at step 3, the SL-MO-LR Response includes the calculated UE locations obtained from step 6.

If requested at step 3, the AMF provides the location results to the AF/LCS Client.