Signaling for round trip time (RTT) based positioning using stronger path tracking

Patent metadata

Field	Value
Publication number	US-11044581-B2
Application number	US-202016746508-A
Country	US
Kind code	B2
Filing date	Jan 17, 2020
Priority date	Jan 21, 2019
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

The disclosed methods and apparatuses for round trip time (RTT) based positioning include generating or receiving a measurement report. The measurement report includes, for at least one transmission-reception point (TRP), a user equipment (UE) time difference and an offset of the at least one TRP. The UE time difference is a difference of a UE transmission time of an uplink reference signals (UL RS) to the at least one TRP and an earliest reception time representing a time of arrival (TOA) at the UE of an earliest path of a downlink reference signal (DL RS) from the at least one transmission-reception point (TRP). The offset is a difference of a stronger reception time representing a TOA at the UE of a stronger path of the DL RS from the at least one TRP and the earliest reception time.

First claim

What is claimed is:

1. A method performed by a user equipment (UE), the method comprising:
receiving one or more downlink reference signals (DL RSs) from one or more transmission-reception points (TRPs);
transmitting one or more uplink reference signals (UL RSs) to the one or more TRPs;
generating a measurement report for the one or more TRPs; and
transmitting the measurement report,
wherein the measurement report includes, for at least one TRP of the one or more TRPs, a UE time difference and an offset of the at least one TRP,
wherein the UE time difference is a difference of a UE transmission time of the UL RS to the at least one TRP and an earliest reception time representing a time of arrival (TOA) at the UE of an earliest path of the DL RS from the at least one TRP, and
wherein the offset is a difference of a stronger reception time representing a TOA at the UE of a stronger path of the DL RS from the at least one TRP and the earliest reception time.

2. The method of claim 1 , wherein the UE time difference is defined as UETimeDIFF, UE Rs-Tx =T 3 −T 2 and the offset is defined as Δ s =T 2,s −T 2 , in which:
T 2 is the earliest reception time at the UE,
T 2,s is the stronger reception time at the UE, and
T 3 is the UE transmission time.

3. The method of claim 1 , wherein receiving the one or more DL RSs comprises:
for each DL RS,
measuring the earliest reception time of the earliest path of that DL RS;
determining whether the stronger path of that DL RS is to be tracked;
determining whether the stronger path of that DL RS is found when it is determined that the stronger path of that DL RS is to be tracked; and
measuring the stronger reception time of the stronger path of that DL RS when it is determined that the stronger path of that DL RS is found.

4. The method of claim 3 , wherein it is determined that the stronger path of a DL RS is to be tracked when any one or more of the following conditions are met:
the UE is preconfigured to track the stronger path,
the UE is dynamically configured by a serving TRP to track the stronger path,
the TRP transmitting the DL RS is configured to track a stronger path of the UL RS transmitted to the TRP by the UE,
a bandwidth of the UL RS transmitted to the TRP by the UE is less than or equal to an UL bandwidth threshold; or
the UE is power limited on UL transmissions to the TRP at or below an UL power threshold.

5. The method of claim 3 , wherein it is determined that the stronger path of a DL RS is found when a non-direct path signal of the DL RS has a strength greater than the earliest path is found.

6. The method of claim 3 , wherein it is determined that the stronger path of a DL RS is found when a non-direct path signal of the DL RS whose strength is greater than the earliest path is found within a strength threshold window of the earliest reception time, the UE being preconfigured with the strength threshold window and/or dynamically configured by a serving TRP.

7. The method of claim 3 , wherein it is determined that the stronger path of a DL RS is found when a non-direct path signal of the DL RS whose strength is greater than the earliest path by at least a strength differential threshold is found, the UE being preconfigured with the strength differential threshold and/or dynamically configured by a serving TRP.

8. The method of claim 3 , wherein it is determined that the stronger path of a DL RS is found when a non-direct path signal of the DL RS whose strength is greater than the earliest path by at least a strength differential threshold is found within a strength threshold window of the earliest reception time, the UE being preconfigured with the strength threshold window and/or the strength differential threshold and/or dynamically configured by a serving TRP.

9. The method of claim 1 , wherein transmitting the one or more UL RSs comprises:
receiving a timing advance (TA) command from a serving TRP;
determining whether all TA adjust conditions are met, wherein the TA adjust conditions include tracking the stronger path is in effect, the one or more UL RSs are only used for positioning purpose, and there are no other UL channels adjacent to the one or more UL RSs;
adjusting the TA command for the one or more UL RSs and transmitting the one or more UL RSs with the adjusted TA command, if all TA adjust conditions are met; and
transmitting the one or more UL RSs without adjusting the TA command, if all TA adjust conditions are not met.

10. The method of claim 1 , wherein generating the measurement report comprises:
for each DL RS,
calculating the UE time difference intended for a TRP;
if it is determined that the stronger path of that DL RS is to be tracked:
determining the offset of that DL RS; and
incorporating the UE time difference and the offset in the measurement report; and

if it is not determined that the stronger path of that DL RS is to be tracked, incorporating the UE time difference in the measurement report and omitting the offset in the measurement report.

11. The method of claim 10 , wherein incorporating the UE time difference and the offset comprises incorporating the UE time difference and the offset as separate quantities in the measurement report.

12. The method of claim 11 , wherein the UE time difference and the offset are packaged with a same step size in the measurement report.

13. The method of claim 10 , wherein incorporating the UE time difference and the offset comprises jointly encoding the UE time difference and the offset into one quantity in the measurement report.

14. The method of claim 13 , wherein the UE time difference and the offset are jointly into a quantity (T 3 −T 2 +Δ s ) in the measurement report, in which:
T 2 is the earliest reception time at the UE,
T 3 is the UE transmission time, and
Δ s is the offset of the at least one TRP.

15. The method of claim 1 , wherein the measurement report includes for at least one other TRP a UETimeDIFF UE Rs-Tx =T 3 −T 2 of the at least one other TRP, but does not include the offset of the at least one other TRP, where:
T 2 is the earliest reception time at the UE, and
T 3 is the UE transmission time.

16. The method of claim 1 , wherein the one or more DL RSs are positioning reference signals (PRS) and the one or more UL RSs are sounding reference signals (SRS).

17. The method of claim 1 , wherein the stronger path is at least one of:
a first path that is X dB stronger than the earliest path,
a second path that is X dB stronger than the earliest path and within a given time window, or
a strongest path that is at least X nsec away from the TOA of the earliest path.

18. The method of claim 1 , wherein the one or more UL RSs correspond to the one or more DL RSs.

19. The method of claim 1 , wherein the measurement report is transmitted to a serving TRP.

20. The method of claim 1 , wherein for the at least one TRP, the UE time difference and the offset are transmitted in separate UL packages.

21. A method performed by a transmission-reception point (TRP), the method comprising:
transmitting a downlink reference signal (DL RS) to a user equipment (UE) at T 1
receiving an uplink reference signal (UL RS) corresponding to the DL RS; and
receiving a measurement report from the UE,
wherein the measurement report includes a UE time difference and an offset of the TRP,
wherein the UE time difference is a difference of a UE transmission time of the UL RS to the TRP and an earliest reception time represe

Assignees

• Qualcomm Inc

Inventors

• Manolakos Alexandras
• Sundararajan Jay Kumar
• Soriaga Joseph Binamira
• Ji Tingfang

Classifications

• H04W64/00 Primary

  Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management · CPC title

• H04W56/0065

  using measurement of signal travel time · CPC title

• H04W56/0005

  synchronizing of arrival of multiple uplinks · CPC title

• H04W24/10

  Scheduling measurement reports {; Arrangements for measurement reports} · CPC title

• G01S5/14

  Determining absolute distances from a plurality of spaced points of known location · CPC title