Content for &nbsp; TS 38.305 &nbsp; Word version:&nbsp; 17.5.0

The LMF may receive information on the possible On-Demand PRS configurations that the gNB can support during the TRP Information Exchange procedure.

Figure 7.7.2-1: Pre-configured measurement gap configuration and activation procedure

In case of UE-initiated On-Demand PRS, the LMF may configure the UE with pre-defined PRS configurations via LPP Provide Assistance Data message or via posSI.

Step 2a.

In case of UE-initiated On-Demand PRS, the UE sends an On-Demand PRS request to the LMF via LPP Request Assistance Data message. The On-Demand PRS request can be a request for a pre-defined PRS configuration indicated with pre-defined PRS configuration ID or explicit parameter for PRS configuration and may be a request for PRS transmission or change to the PRS transmission characteristics for positioning measurements.

Step 2b.

In case of LMF-initiated On-Demand PRS, the LMF and the UE may exchange LPP messages e.g., to obtain UE measurements or the DL-PRS positioning capabilities of the UE, etc.

Step 3.

The LMF determines the need for PRS transmission or change to the transmission characteristics of an ongoing PRS transmission.

Step 4.

The LMF requests the serving and non-serving gNBs/TRPs for new PRS transmission or PRS transmission with changes to the PRS configuration via NRPPa PRS CONFIGURATION REQUEST message.

Step 5.

The gNBs/TRPs provide the successfully configured or updated PRS transmission in the NRPPa PRS CONFIGURATION RESPONSE message accordingly.

Step 6.

LMF may provide the PRS configuration used for PRS transmission or error cause via LPP Provide Assistance Data message to the UE.

7.7 Procedures for Pre-configured Measurement Gap |R17| p. 47

7.7.1 General p. 47

The pre-configured measurement gap procedure is used by the network to provide measurement gap for NR DL-PRS measurements. The serving gNB may activate/deactivate the pre-configured measurement gap upon receiving the request from a UE or LMF.

7.7.2 Pre-configured Measurement Gap procedures p. 47

Figure 7.7.2-1 shows the procedure for the successful pre-configuration and activation of measurement gap.

Reproduction of 3GPP TS 38.305, Fig. 7.7.2-1: Pre-configured measurement gap configuration and activation procedure

LMF obtains the TRP information required for positioning services from the gNBs.

The LMF provides the PRS information of the neighbour TRPs to the serving gNB and requests the serving gNB to configure the UE with measurement pre-configurations via NRPPa MEASUREMENT PRECONFIGURATION REQUIRED message.

Figure 7.7.2-2: Pre-configured measurement gap deactivation procedure

Based on the assistance information from the LMF and the UE capability, the serving gNB decides to pre-configure the UE with measurement gap and provides pre-configured measurement gap configuration(s) with associated ID(s) to the UE by sending RRC Reconfiguration message specified in TS 38.331.

Step 3.

The UE sends RRC Reconfiguration complete message to the serving gNB to confirm the reception of pre-configured measurement gap configuration(s).

Step 4.

The serving gNB sends the confirmation message to the LMF to indicate the success of the pre-configuration via NRPPa MEASUREMENT PRECONFIGURATION CONFIRM message.

Step 5a.

If the UE requires measurement gaps for performing the requested location measurements, and the triggering condition for UL MAC CE as specified in TS 38.331 is met, the UE sends UL MAC CE Positioning Measurement Gap Activation/Deactivation Request to the serving gNB and indicates the requested measurement gap configuration based on the ID configured in step 2.

Step 5b.

LMF may send the NRPPa MEASUREMENT ACTIVATION message to request the serving gNB to activate pre-configured measurement gap.

Step 6.

Based on the request from the UE in step 5a or the request from the LMF in step 5b, the serving gNB may send DL MAC CE Positioning Measurement Gap Activation/Deactivation Command containing an ID to activate the associated measurement gap.

Figure 7.7.2-2 shows the procedure for the successful deactivation of measurement gap.

Reproduction of 3GPP TS 38.305, Fig. 7.7.2-2: Pre-configured measurement gap deactivation procedure

A measurement gap has been activated as shown in Figure 7.7.2-1.

Step 1a.

If the UE requires to stop performing the requested location measurements, and the triggering condition for UL MAC CE as specified in TS 38.331 is met, the UE sends UL MAC CE Positioning Measurement Gap Activation/Deactivation Request to the serving gNB to deactivate the activated measurement gap containing the ID associated with the measurement gap for positioning.

Step 1b.

LMF may send the NRPPa MEASUREMENT ACTIVATION message to request the serving gNB to deactivate pre-configured measurement gap.

Figure 7.8.2-1: Pre-configured PRS processing window configuration and activation procedure

Based on the request from the UE in step 1a or the request from the LMF in step 1b, the serving gNB may send DL MAC CE Positioning Measurement Gap Activation/Deactivation Command containing an ID to deactivate the associated measurement gap.

7.8 Procedures for Pre-configured PRS processing window |R17| p. 49

7.8.1 General p. 49

The pre-configured PRS processing window procedure is used by the network to provide PRS processing window for NR DL-PRS measurements to the UE without measurement gap. The serving gNB may activate/deactivate the pre-configured PRS processing window upon receiving the request from LMF.

7.8.2 Pre-configured PRS processing window procedures p. 49

Figure 7.8.2-1 shows the procedure for the successful pre-configuration and activation of PRS processing window.

Reproduction of 3GPP TS 38.305, Fig. 7.8.2-1: Pre-configured PRS processing window configuration and activation procedure

LMF obtains the TRP information required for positioning services from the gNBs.

Figure 7.8.2-2: Pre-configured PRS processing window deactivation procedure

Based on the assistance information from the LMF and the UE capability, the serving gNB decides to pre-configure the UE with PRS processing window and provides pre-configured PRS processing window configuration(s) with associated ID(s) to the UE by sending RRC Reconfiguration message specified in TS 38.331.

Step 3.

The UE sends RRC Reconfiguration complete message to the serving gNB to confirm the reception of pre-configured PRS processing window configuration(s).

Step 4.

The serving gNB sends the confirmation message to the LMF to indicate the success of the pre-configuration via NRPPa MEASUREMENT PRECONFIGURATION CONFIRM message.

Step 5.

The LMF sends the NRPPa MEASUREMENT ACTIVATION message to request the serving gNB to activate the pre-configured PRS processing window.

Step 6.

Based on the request from the LMF in step 5, the serving gNB sends DL MAC CE PPW Activation/Deactivation Command containing ID(s) to activate the associated PRS processing window configuration(s).

Figure 7.8.2-2 shows the procedure for the successful deactivation of PRS processing window.

Reproduction of 3GPP TS 38.305, Fig. 7.8.2-2: Pre-configured PRS processing window deactivation procedure

The PRS processing window has been activated as shown in Figure 7.8.2-1.

The LMF sends the NRPPa MEASUREMENT ACTIVATION message to request the serving gNB to deactivate the pre-configured PRS processing window.