5.26 Positioning SRS transmission in RRC_INACTIVE

38.3213GPPMedium Access Control (MAC) protocol specificationNRRelease 17TS

5.26.1 General

Periodic and semi-persistent Positioning SRS can be configured for Positioning SRS transmission in RRC_INACTIVE.

The MAC entity shall, if the TA of the configured Positioning SRS is valid according to clause 5.26.2:

– transmit Positioning Periodic SRS or Semi-Persistent SRS defined in TS 38.214 [7].

5.26.2 TA validation for SRS transmission in RRC_INACTIVE

RRC configures the following parameters for validation for SRS transmission in RRC_INACTIVE:

– inactivePosSRS-RSRP-ChangeThreshold: RSRP threshold for the increase/decrease of RSRP for time alignment validation.

The MAC entity shall:

1> if the UE receives configuration for SRS transmission in RRC_INACTIVE:

2> store the RSRP of the downlink pathloss reference with the current RSRP value of the downlink pathloss reference as in TS 38.331 [5].

1> else if the UE is configured with SRS transmission in RRC_INACTIVE:

2> if Timing Advance Command MAC CE is received for inactivePosSRS-TimeAlignmentTimer as in clause 5.2, or;

2> if Timing Advance Command or Absolute Timing Advance Command is received for Random Access procedure that is successfully completed:

3> update the stored downlink pathloss reference with the current RSRP value of the downlink pathloss reference.

The MAC entity shall consider the TA to be valid when the following condition is fulfilled:

1> compared to the stored downlink pathloss reference RSRP value, the current RSRP value of the downlink pathloss reference has not increased/decreased by more than inactivePosSRS-RSRP-ChangeThreshold, if configured; and

1> inactivePosSRS-TimeAlignmentTimer is running.