System and methods for supporting uplink and downlink positioning procedures in a wireless network
A position of a user equipment (UE) may be determined using downlink based solutions (e.g. OTDOA), uplink based solutions (e.g. UTDOA), or combined downlink and uplink based solutions (e.g. RTT). The serving gNBs may request neighboring gNBs to produce downlink reference signal transmissions to a target UE and/or measure uplink reference signal transmissions from the target UE. The serving gNB may receive the uplink reference signal measurements from neighboring gNBs and obtain an own uplink reference signal measurement and forward to the UE or another network entity all the uplink reference signal measurements. The UE may use the uplink reference signal measurements, along with the UE's own downlink reference signal measurements to determine RTTs. The serving gNBs or another entity may keep the uplink reference signal measurements and may determine RTTs after receiving the downlink reference signal measurements from the UE.
1. A method for determining a position of a user equipment (UE) performed by the UE, the method comprising:
receiving, from a serving gNB, assistance data for a plurality of gNBs, which includes the serving gNB;
transmitting, to the plurality of gNBs, uplink reference signals;
receiving, from the serving gNB, uplink reference signal measurements measured by each of the plurality of gNBs, wherein the serving gNB received the uplink reference signal measurements measured by other gNBs in the plurality of gNBs;
determining a round trip time (RTT) for each gNB in the plurality of gNBs using the uplink reference signal measurements measured by each of the plurality of gNBs and downlink reference signals measurements performed by the UE upon downlink reference signals received from the plurality of gNBs; and
determining the position of the UE based on performing multilateration with the RTT for each gNB and a location of each gNB received in the assistance data.
2. The method of claim 1 , wherein determining the position for the UE uses Uplink Time Difference of Arrival (UTDOA), and wherein the reference signal measurements measured by each of the plurality of gNBs is one of a Time of Arrival (TOA) measurement or a gNB Rx-Tx Time difference measurement.
3. The method of claim 1 , further comprising:
transmitting to the serving gNB a request for location;
wherein the serving gNB generates and transmits to the UE the assistance data for the plurality of gNBs in response to the request for location.
4. A user equipment (UE) configured for determining a position of the UE, the UE comprising:
a transceiver configured to communicate with gNBs;
at least one memory; and
at least one processor coupled to the transceiver and the at least one memory, the at least one processor configured to:
receive, via the transceiver from a serving gNB, assistance data for a plurality of gNBs, which includes the serving gNB;
transmit, via the transceiver to the plurality of gNBs, uplink reference signals for each of the plurality of gNBs to perform an uplink reference signal measurement;
receive, via the transceiver from the serving gNB, uplink reference signal measurements measured by each of the plurality of gNBs, wherein the serving gNB received the uplink reference signal measurements measured by other gNBs in the plurality of gNBs;
determine a round trip time (RTT) for each gNB in the plurality of gNBs using the uplink reference signal measurements measured by each of the plurality of gNBs and downlink reference signals measurements performed by the UE upon downlink reference signals received from the plurality of gNBs; and
determine the position of the UE based on performing multilateration with the RTT for each gNB and a location of each gNB received in the assistance data.
5. The UE of claim 4 , wherein the at least one processor is configured to determine the position for the UE using Uplink Time Difference of Arrival (UTDOA) and wherein the uplink reference signal measurement performed by each of the plurality of gNBs is one of a Time of Arrival (TOA) measurement or a gNB Rx-Tx Time difference Measurement.
6. The UE of claim 4 , wherein the at least one processor is further configured to:
transmit via the transceiver to the serving gNB a request for location;
wherein the serving gNB generates and transmits to the UE the assistance data for the plurality of gNBs in response to the request for location.
7. A method for determining a position of a user equipment (UE) performed by a serving gNB for the UE, the method comprising:
receiving a location request for the UE from another entity;
determining a plurality of neighbor gNBs;
sending a request to each neighbor gNB in the plurality of neighbor gNBs to increase downlink reference signal transmissions and to measure uplink reference signal transmissions from the UE;
generating assistance data for the plurality of neighbor gNBs;
transmitting the assistance data for the plurality of neighbor gNBs to the UE;
receiving an uplink reference signal transmission from the UE;
generating an uplink reference signal measurement for the uplink reference signal transmission;
receiving one or more uplink reference signal measurements measured by each neighbor gNB in the plurality of neighbor gNBs, wherein the one or more uplink reference signal measurements are generated from uplink reference signal transmissions from the UE to the neighbor gNBs;
determining a round trip time (RTT) for each gNB using the uplink reference signal measurements measured by each gNB and downlink reference signals measurements measured by the UE;
determining the position of the UE based on performing multilateration with the RTT for each gNB and a known location of each gNB; and
transmitting location information to the other entity.
8. The method of claim 7 , wherein the location information is a location measurement message that includes the uplink reference signal measurement from the serving gNB and the one or more uplink reference signal measurements from the neighbor gNBs, and wherein the location measurement message is transmitted to the UE for determination of the position of the UE.
9. The method of claim 8 , wherein the determination of the position of the UE is performed by the UE using Uplink Time Difference of Arrival (UTDOA).
10. The method of claim 8 , wherein the other entity is the UE and wherein the assistance data is generated and transmitted to the UE in response to the location request.
11. The method of claim 7 , wherein the location information is a location measurement message that includes the uplink reference signal measurement from the serving gNB and the one or more uplink reference signal measurements from the neighbor gNBs, and wherein the location measurement message is transmitted to a network entity.
12. A gNB configured for determining a position of a user equipment (UE), wherein the gNB is a serving gNB for the UE, comprising:
at least one external interface configured to communicate with the UE, with other gNBs and with entities in a wireless network;
at least one memory; and
at least one processor coupled to the at least one external interface and the at least one memory, the at least one processor configured to:
receive a location request for the UE from another entity;
determine a plurality of neighbor gNBs;
send a request to each neighbor gNB in the plurality of neighbor gNBs to increase downlink reference signal transmissions and to measure uplink reference signal transmissions from the UE;
generate assistance data for the plurality of neighbor gNBs;
transmit via the at least one external interface the assistance data for the plurality of neighbor gNBs to the UE;
receive via the at least one external interface an uplink reference signal transmission from the UE;
generate an uplink reference signal measurement for the uplink reference signal transmission;
receive via the at least one external interface one or more uplink reference signal measurements measured by each neighbor gNB in the plurality of neighbor gNBs, wherein the one or more uplink reference signal measurements are generated from uplink reference signal transmissions from the UE to the neighbor gNBs;
determine a round trip time (RTT) for each gNB using the uplink reference signal measurements measured by each gNB and downlink reference signals measurements measured by the UE;
determine the position of the UE based on performing multilateration with the RTT for each gNB and a known location of each gNB; and
transmit via the at least one external interface location information of the UE to the other entity.
13. The gNB of claim 12 , wherein the location information is a location measurement message that includes the uplink reference signal measurement from the serving gNB and the one or more uplink reference signal measurements from the neighbor gNBs, and wherein the location measurement message is transmitted to the UE for determination of the position of the UE.
14. The gNB of claim 13 , wherein the determination of the position of the UE is performed by the UE using Uplink Time Difference of Arrival (UTDOA).
15. The gNB of claim 13 , wherein the other entity is the UE and wherein the assistance data is generated and transmitted to the UE in response to the location request.
16. The gNB of claim 12 , wherein the location information is a location measurement message that includes the uplink reference signal measurement from the serving gNB and the one or more uplink reference signal measurements from the neighbor gNBs, and wherein the location measurement message is transmitted to a network entity.