Group reporting of user equipment measurements in multi-round trip time positioning
Disclosed are techniques for group reporting of UE receive-transmit (Rx-Tx) time difference measurements for multi-RTT positioning. A plurality of downlink reference signals (DL RSs) are received from a plurality of transmission reception points (TRPs). A corresponding plurality of uplink reference signals (UL RSs) are transmitted to the plurality of TRPs. One or more numerology factors are determined for the plurality of TRPs. A measurement report is generated for the plurality of TRPs based on the numerology factors. The measurement report is transmitted to a network entity. The measurement report includes UE receive-transmit (Rx-Tx) time difference measurements for at least two of the TRPs.
1. A method performed by a user equipment (UE), the method comprising:
receiving a plurality of downlink reference signals (DL RSs) from a plurality of transmission reception points (TRPs);
transmitting a corresponding plurality of uplink reference signals (UL RSs) to the plurality of TRPs; and
transmitting a measurement report for the plurality of TRPs to a network entity, wherein the measurement report is generated based on one or more numerology factors, wherein the measurement report includes a receive-transmit (Rx-Tx) time difference for at least two TRPs of the plurality of TRPs, and wherein a step size for reporting the Rx-Tx time difference is based on a time unit T c and the one or more numerology factors.
2. The method of claim 1 , wherein the Rx-Tx time difference for each TRP is denoted as UE Rx-Tx,k (time_diff) for each TRP k of the plurality of TRPs, where k is an integer, is defined as T UE,Rx,k −T UE,Tx,k in which T UE,Rx,k is a UE received timing of a downlink (DL) radio subframe from the TRP k, and T UE,Tx,k is the UE transmit time of corresponding uplink (UL) radio subframe to the TRP k.
3. The method of claim 1 , wherein each DL RS is a positioning reference signal (PRS) and each UL RS is a sounding reference signal (SRS) for positioning.
4. The method of claim 1 , wherein a numerology factor of the one or more numerology factors of a TRP k of the plurality of TRPs, where kis an integer, is configured separately from configuring of a subcarrier spacing (SCS) of a DL RS received from the TRP k and independent of a SCS of a UL RS transmitted to the TRP k.
5. The method of claim 1 , wherein a numerology factor of the one or more numerology factors of a TRP k of the plurality of TRPs, where k is an integer, is determined based on at least one of one or more characteristics of a DL RS received from the TRP k or one or more characteristics of a UL RS transmitted to the TRP k.
6. The method of claim 5 , wherein the numerology factor of the TRP k is determined:
based on a larger subcarrier spacing (SCS) of the DL RS and the UL RS,
based on a smaller subcarrier spacing (SCS) of the DL RS and the UL RS,
based on a bandwidth of the DL RS or a bandwidth of the UL RS,
as a function of min(the bandwidth of the DL RS, the bandwidth of the UL RS), or
as a function of max(the bandwidth of the DL RS, the bandwidth of the UL RS).
7. The method of claim 1 , wherein a same numerology factor is assigned for all TRPs.
8. The method of claim 1 , wherein the measurement report includes, for a TRP k, of the plurality of TRPs, where k is an integer, a Rx-Tx time difference field configured to hold a Rx-Tx time difference of the TRP k, and
wherein for at least one TRP n, of the plurality of TRPs, where n is an integer, an entire width of a Rx-Tx time difference field for TRP n is used to hold a Rx-Tx time difference of the TRP n.
9. The method of claim 1 , wherein generating the measurement report comprises:
determining one or more TRP groups;
determining, for each TRP group, a reference TRP having a Rx-Tx time difference (UE Rx-Tx ) as a reference UE Rx-Tx for each TRP group; and
determining, for each non-reference TRP of each TRP group, a differential UE Rx-Tx for each non-reference TRP from the reference UE Rx-Tx of each TRP group.
10. The method of claim 9 , wherein the one or more TRP groups are determined such that within each TRP group, a numerology factor of the one or more numerology factors is a same value for all member TRPs of each TRP group.
11. The method of claim 9 , wherein the one or more TRP groups along with the reference TRP of each TRP group are explicitly configured.
12. The method of claim 9 , wherein for at least one TRP group of the one or more TRP groups at least one of:
all member TRPs transmit positioning reference signals (PRSs) on a same slot,
all member TRPs transmit positioning reference signals (PRSs) on a same frame, or
all member TRPs transmit positioning reference signals (PRSs) on same symbols.
13. The method of claim 9 , wherein the one or more TRP groups are determined such that for at least one TRP group of the one or more TRP groups, a sounding reference signal (SRS) configuration is associated with member TRPs of the at least one TRP group.
14. The method of claim 9 , wherein the one or more TRP groups are determined based on at least one of timing advance (TA) commands or different timing advance groups (TAGs).
15. The method of claim 9 , wherein a number of bits for representing the differential UE Rx-Tx of each non-reference TRP is less than a number of bits of a time_diff field representing the reference UE Rx-rx of the reference TRP.
16. A user equipment (UE) comprising:
a transceiver; and
a processor communicatively coupled to a memory and the transceiver, wherein the processor is configured to:
receive, via the transceiver, a plurality of downlink reference signals (DL RSs) from a plurality of transmission reception points (TRPs);
transmit, via the transceiver, a corresponding plurality of uplink reference signals (UL RSs) to the plurality of TRPs; and
transmit, via the transceiver, a measurement report for the plurality of TRPs to a network entity, wherein the measurement report is generated based on one or more numerology factors, wherein the measurement report includes a receive-transmit (Rx-Tx) time difference for at least two TRPs of the plurality of TRPs, and wherein a step size for reporting the Rx-Tx time difference is based on a time unit T c and the one or more numerology factors.
17. The UE of claim 16 , wherein the Rx-Tx time difference for each TRP is denoted as UE Rx-Tx,k (time_diff) for each TRP k of the plurality of TRPs, where k is an integer, is defined as T UE,Rx,k −T UE,Tx,k in which T UE,Rx,k is a UE received timing of a downlink (DL) radio subframe from the TRP k, and T UE,Tx,k is the UE transmit time of corresponding uplink (UL) radio subframe to the TRP k.
18. The UE of claim 16 , wherein each DL RS is a positioning reference signal (PRS) and each UL RS is a sounding reference signal (SRS) for positioning.
19. The UE of claim 16 , wherein a numerology factor of the one or more numerology factors of a TRP k of the plurality of TRPs, where k is an integer, is configured separately from configuring of a subcarrier spacing (SCS) of a DL RS received from the TRP k and independent of a SCS of a UL RS transmitted to the TRP k.
20. The UE of claim 16 , wherein a numerology factor of the one or more numerology factors of a TRP k of the plurality of TRPs, where k is an integer, is determined based on at least one of one or more characteristics of a DL RS received from the TRP k or one or more characteristics a UL RS transmitted to the TRP k.
21. The UE of claim 20 , wherein the numerology factor of the TRP k is determined:
based on a larger subcarrier spacing (SCS) of the DL RS and the UL RS,
based on a smaller subcarrier spacing (SCS) of the DL RS and the UL RS,
based on a bandwidth of the DL RS or a bandwidth of the UL RS,
as a function of min(the bandwidth of the DL RS, the bandwidth of the UL RS), or
as a function of max(the bandwidth of the DL RS, the bandwidth of the UL RS).
22. The UE of claim 16 , wherein a same numerology factor is assigned for all TRPs.
23. The UE of claim 16 , wherein the measurement report includes, for a TRP k, of the plurality of TRPs, where k is an integer, a Rx-Tx time difference field configured to hold a Rx-Tx time difference of the TRP k, and
wherein for at least one TRP n, of the plurality of TRPs, where n is an integer, an entire width of a Rx-Tx time difference field for TRP n is used to hold a Rx-Tx time difference of the TRP n.
24. The UE of claim 16 , wherein the processor configured to generate the measurement report further comprises the processor being configured to:
determine one or moreTRP groups;
determine, for each TRP group, a reference TRP having a Rx-Tx time difference (UE Rx-Tx ) as a reference UE Rx-Tx for each TRP group; and
determine, for each non-reference TRP of each TRP group, a differential UE Rx-Tx for each non-reference TRP from the reference UE R,Tx of each TRP group.
25. The UE of claim 24 , one or more TRP groups are determined such that within each TRP group, a numerology factor of the one or more numerology factors is a same value for all member TRPs of each TRP group.
26. The UE of claim 24 , wherein the one or more TRP groups along with the reference TRP of each TRP group are explicitly configured.
27. The UE of claim 24 , for at least one TRP group of the one or more TRP groups at least one of:
all member TRPs transmit positioning reference signals (PRSs) on a same slot,
all member TRPs transmit positioning reference signals (PRSs) on a same frame, or
all member TRPs transmit positioning reference signals (PRSs) on same symbols.
28. The UE of claim 24 , wherein the one or more TRP groups are determined such that for at least one TRP group of the one or more TRP groups, a sounding reference signal (SRS) configuration is associated with member TRPs of the at least one TRP group.
29. The UE of claim 24 , wherein the one or more TRP groups are determined based on at least one of timing advance (TA) commands or different timing advance groups (TAGs).
30. The UE of claim 24 , wherein a number of bits for representing the differential UE Rx-Tx of each non-reference TRP is less than a number of bits of a time_diff field representing the reference UE Rx-Tx of the reference TRP.
31. A user equipment (UE) comprising:
means for receiving a plurality of downlink reference signals (DL RSs) from a plurality of transmission reception points (TRPs);
means for transmitting a corresponding plurality of uplink reference signals (UL RSs) to the plurality of TRPs; and
means for transmitting a measurement report for the plurality of TRPs to a network entity, wherein the measurement report is generated based on one or more numerology factors, wherein the measurement report includes a receive-transmit (Rx-Tx) time difference for at least two TRPs of the plurality of TRPs, and wherein a step size for reporting the Rx-Tx time difference is based on a time unit T c and the one or more numerology factors.
32. The UE of claim 31 , wherein the Rx-Tx time difference for each TRP is denoted as UE Rx-Tx,k (time_diff) for each TRP k of the plurality of TRPs, where k is an integer, is defined as T UE,Rx,k −T UE,Tx,k in which T UE,Rx,k is a UE received timing of a downlink (DL) radio subframe from the TRP k, and T UE,Tx,k is the UE transmit time of corresponding uplink (UL) radio subframe to the TRP k.