Systems and methods for PRS muting in a fifth generation wireless network
Methods and techniques are described for supporting location services for a user equipment (UE) in a Fifth Generation wireless network in which a base station, such as a gNB or ng-eNB, broadcasts a Positioning Reference Signal (PRS) in a plurality of different directions and at a plurality of different times. A PRS muting configuration is used in which PRS is muted using a time based and angle based pattern to prevent interference between beams transmitted by other base stations and/or to prevent interference between beams transmitted simultaneously by a single base station. The time based and angle based muting pattern, for example, may provide an indication for each direction in the plurality of different directions and for each time in the plurality of different times and as to whether the PRS is transmitted or muted by the base station.
1. A method for supporting location services for a user equipment (UE) performed by a location server comprising:
determining configuration parameters for a Positioning Reference Signal (PRS) transmitted by a base station, the configuration parameters comprising a muting configuration, the muting configuration comprising a time based and angle based muting pattern;
generating assistance data for the UE based on the configuration parameters, the assistance data comprising the muting configuration;
sending the assistance data to the UE; and
receiving location information from the UE, wherein the location information is based on at least one location measurement for the PRS, wherein the at least one location measurement is based on the muting configuration.
2. The method of claim 1 , wherein sending the assistance data to the UE comprises sending the assistance data to the UE as part of a message to the UE.
3. The method of claim 1 , wherein sending the assistance data to the UE comprises sending the assistance data to the base station and the base station broadcasts the assistance data to the UE.
4. The method of claim 1 , further comprising determining a location for the UE based at least in part on the location information.
5. The method of claim 4 , wherein the location information comprises the at least one location measurement or the location.
6. The method of claim 1 , wherein the base station is a New Radio (NR) NodeB (gNB) or a Next Generation evolved NodeB (ng-eNB) in a Fifth Generation (5G) wireless network and the location server is a Location Management Function (LMF).
7. The method of claim 1 , wherein the PRS is transmitted by the base station in a plurality of different directions and at a plurality of different times.
8. The method of claim 7 , wherein the PRS is transmitted in different directions in the plurality of different directions at the same times in the plurality of different times.
9. The method of claim 7 , wherein the PRS is transmitted in different directions in the plurality of different directions at different times in the plurality of different times.
10. The method of claim 7 , wherein the time based and angle based muting pattern comprises an indication, for each direction in the plurality of different directions and for each time in the plurality of different times, as to whether the PRS is transmitted or muted by the base station.
11. The method of claim 1 , wherein determining the configuration parameters for the PRS further comprises:
sending an information request to the base station; and
receiving an information response from the base station, the information response including the configuration parameters for the PRS.
12. The method of claim 11 , wherein the information request and the information response are Long Term Evolution (LTE) Positioning Protocol A (LPPa) or New Radio Position Protocol A (NRPPa) messages for Observed Time Difference of Arrival (OTDOA) information and OTDOA information response.
13. The method of claim 1 , wherein the time based and angle based muting pattern comprises a time based muting pattern comprising a plurality of beam sweeps wherein each beam sweep has an angular based muting pattern indicating an angular range at which the PRS is muted, and wherein the plurality of beam sweeps use one or more angular based muting patterns.
14. The method of claim 13 , wherein the time based muting pattern and the one or more angular based muting patterns are configured so that a directional beam produced by the base station mutes the PRS at a first angular range at which the directional beam intersects a second directional beam with a non-muted PRS from a second base station during a first beam sweep and does not mute the PRS at the first angular range at which the directional beam intersects the second directional beam with a muted PRS from the second base station during a second beam sweep.
15. The method of claim 1 , wherein the base station transmits multiple beams simultaneously, each beam being transmitted in a different angular range, wherein the time based and angle based muting pattern comprises independently scheduled time based muting patterns for beams being transmitted in the different angular range.
16. The method of claim 15 , wherein the independently scheduled time based muting patterns for the beams being transmitted in the different angular range are configured to reduce interference between the PRS from separate beams being transmitted simultaneously by the base station.
17. The method of claim 15 , wherein the independently scheduled time based muting patterns for the beams are configured to reduce any interference from PRS from beams transmitted by other base stations.
18. The method of claim 1 , wherein the time based and angle based muting pattern is defined by a two-dimensional muting pattern across time and angular direction.
19. The method of claim 1 , wherein the at least one location measurement comprises one or more of a Reference Signal Time Difference (RSTD), a Receive-Transmit (Rx-Tx) time difference, an Angle of Arrival (AOA), an Angle of Departure (AOD), a Reference Signal Received Power (RSRP), and a Reference Signal Received Quality (RSRQ).
20. A location server for supporting location services for a user equipment (UE), the location server comprising:
an external interface configured to communicate with a wireless network;
at least one memory; and
at least one processor coupled to the external interface and the at least one memory and configured to:
determine configuration parameters for a Positioning Reference Signal (PRS) transmitted by a base station, the configuration parameters comprising a muting configuration, the muting configuration comprising a time based and angle based muting pattern;
generate assistance data for the UE based on the configuration parameters, the assistance data comprising the muting configuration;
send the assistance data to the UE via the external interface; and
receive location information from the UE via the external interface, wherein the location information is based on at least one location measurement for the PRS, wherein the at least one location measurement is based on the muting configuration.
21. The location server of claim 20 , wherein the at least one processor is configured to send the assistance data to the UE by being configured to send the assistance data to the UE as part of a message to the UE.
22. The location server of claim 20 , wherein the at least one processor is configured to send the assistance data to the UE by being configured to send the assistance data to the base station and the base station broadcasts the assistance data to the UE.
23. The location server of claim 20 , wherein the at least one processor is further configured to determine a location for the UE based at least in part on the location information.
24. The location server of claim 23 , wherein the location information comprises the at least one location measurement or the location.
25. The location server of claim 20 , wherein the base station is a New Radio (NR) NodeB (gNB) or a Next Generation evolved NodeB (ng-eNB) in a Fifth Generation (5G) wireless network and the location server is a Location Management Function (LMF).
26. The location server of claim 20 , wherein the PRS is transmitted by the base station in a plurality of different directions and at a plurality of different times.
27. The location server of claim 26 , wherein the PRS is transmitted in different directions in the plurality of different directions at the same times in the plurality of different times.
28. The location server of claim 26 , wherein the PRS is transmitted in different directions in the plurality of different directions at different times in the plurality of different times.
29. The location server of claim 26 , wherein the time based and angle based muting pattern comprises an indication for each direction in the plurality of different directions and for each time in the plurality of different times, as to whether the PRS is transmitted or muted by the base station.
30. The location server of claim 20 , wherein the at least one processor is configured to determine the configuration parameters for the PRS by being configured to:
send an information request to the base station via the external interface; and
receive an information response from the base station via the external interface, the information response including the configuration parameters for the PRS.
31. The location server of claim 30 , wherein the information request and the information response are Long Term Evolution (LTE) Positioning Protocol A (LPPa) or New Radio Position Protocol A (NRPPa) messages for Observed Time Difference of Arrival (OTDOA) information and OTDOA information response.
32. The location server of claim 20 , wherein the time based and angle based muting pattern comprises a time based muting pattern comprising a plurality of beam sweeps wherein each beam sweep has an angular based muting pattern indicating an angular range at which the PRS is muted, and wherein the plurality of beam sweeps use one or more angular based muting patterns.
33. The location server of claim 32 , wherein the time based muting pattern and the one or more angular based muting patterns are configured so that a directional beam produced by the base station mutes the PRS at a first angular range at which the directional beam intersects a second directional beam with a non-muted PRS from a second base station during a first beam sweep and does not mute the PRS at the first angular range at which the directional beam intersects the second directional beam with a muted PRS from the second base station during a second beam sweep.
34. The location server of claim 20 , wherein the base station transmits multiple beams simultaneously, each beam being transmitted in a different angular range, wherein the time based and angle based muting pattern comprises independently scheduled time based muting patterns for beams being transmitted in the different angular range.
35. The location server of claim 34 , wherein the independently scheduled time based muting patterns for the beams being transmitted in the different angular range are configured to reduce interference between the PRS from separate beams being transmitted simultaneously by the base station.
36. The location server of claim 34 , wherein the independently scheduled time based muting patterns for the beams are is configured to reduce any interference from PRS from beams transmitted by other base stations.
37. The location server of claim 20 , wherein the time based and angle based muting pattern is defined by a two-dimensional muting pattern across time and angular direction.
38. The location server of claim 20 , wherein the at least one location measurement comprises one or more of a Reference Signal Time Difference (RSTD), a Receive-Transmit (Rx-Tx) time difference, an Angle of Arrival (AOA), an Angle of Departure (AOD), a Reference Signal Received Power (RSRP), and a Reference Signal Received Quality (RSRQ).
39. A location server for supporting location services for a user equipment (UE), the location server comprising:
means for determining configuration parameters for a Positioning Reference Signal (PRS) transmitted by a base station, the configuration parameters comprising a muting configuration, the muting configuration comprising a time based and angle based muting pattern;
means for generating assistance data for the UE based on the configuration parameters, the assistance data comprising the muting configuration;
means for sending the assistance data to the UE; and
means for receiving location information from the UE, wherein the location information is based on at least one location measurement for the PRS, wherein the at least one location measurement is based on the muting configuration.
40. A non-transitory storage medium including program code stored thereon, the program code is operable to cause at least one processor in a location server to support location services for a user equipment (UE), the location server comprising:
program code to determine configuration parameters for a Positioning Reference Signal (PRS) transmitted by a base station, the configuration parameters comprising a muting configuration, the muting configuration comprising a time based and angle based muting pattern;
program code to generate assistance data for the UE based on the configuration parameters, the assistance data comprising the muting configuration;
program code to send the assistance data to the UE; and
program code to receive location information from the UE, wherein the location information is based on at least one location measurement for the PRS, wherein the at least one location measurement is based on the muting configuration.