NR Enhanced Cell ID (NR E-CID) positioning refers to techniques which use UE and/or NR radio resource related measurements to improve the UE location estimate. In the case of uplink NR E-CID inter-RAT E-UTRA measurements reported by UE may also be used.
NR E-CID measurements may include:
UE measurements (TS 38.215):
SS Reference signal received power (SS-RSRP);
SS Reference Signal Received Quality (SS-RSRQ);
CSI Reference signal received power (CSI-RSRP);
CSI Reference Signal Received Quality (CSI-RSRQ).
The UE measurements above may be aggregated at cell level or measured per SSB or CSI-RS resource.
NR E-CID UE measurements for other RAT may include:
UE-assisted NR Enhanced Cell-ID location does not require any assistance data to be transferred from the LMF to the UE.
UE-Based NR Enhanced Cell-ID location is not supported in this version of the specification.
The procedures described in this clause support NR E-CID related measurements obtained by the UE and provided to the LMF using LPP. The term "downlink" is intended to indicate that from the LMF perspective the involved measurements are provided by the UE; this set of procedures might also be considered as "UE-assisted, LMF-based NR E-CID".
The LMF sends a LPP Request Location Information message to the UE for invocation of NR E-CID positioning. This request includes the NR E-CID measurements requested by the LMF and supported by the UE as listed in Table 188.8.131.52-1 together with a required response time.
The UE sends an LPP Provide Location Information message to the LMF and reports the requested measurements that are available in the UE before the Response Time provided in step 1 elapsed. If the requested measurements are not available, or if the Response Time provided in step 1 elapsed before any of the requested measurements have been obtained, the UE returns any information that can be provided in an LPP message of type Provide Location Information which includes a cause indication for the not provided location information.
The procedures described in this clause support NR E-CID related measurements obtained by the serving gNB and provided to the LMF using NRPPa. The term "uplink" is intended to indicate that from the LMF perspective the involved measurements are provided by the serving gNB; this set of procedures might also be considered as "NG-RAN node assisted NR E-CID".
The LMF sends an E-CID Measurement Initiation Request message to the serving gNB to request NR E-CID measurement information. The message includes indication of NR E-CID measurements requested and whether the result is expected only once or periodically.
If the report characteristics in step 1 is set to "on demand", the gNB obtains the requested NR E-CID measurements and returns them in an E-CID Measurement Initiation Response message to the LMF. The E-CID Measurement Initiation Response message includes the obtained NR E-CID measurements as defined in the clause 184.108.40.206.
If the report characteristics in step 1 is set to "periodic", the gNB replies with an E-CID Measurement Initiation Response message without including any measurements in the message. The gNB then periodically initiates the E-CID Measurement Report procedure in step 3 for the NR E-CID measurements, with the requested reporting periodicity.
If the gNB is not able to accept the E-CID Measurement Initiation Request message in step 1, the gNB returns a failure message indicating the cause of the failure.