Methods and apparatuses for positioning based on signal correlation function characteristics feedback
A method, apparatus, and system are provided for facilitating positioning based on signal correlation function characteristic feedback. In an embodiment, the method may involve steps performed by a network node in communication with a 5 wireless communication device (WCD) and a plurality of base stations. The network node receives, from the WCD, location information including position reference signal (PRS) correlation function characteristics of a cross-correlation between a received downlink signal and a transmitted PRS for each base station from the plurality of base stations. The network node determines a position of the WCD using 0 the PRS correlation function characteristics. The WCD may initiate the transmission of the PRS correlation function characteristics on its own, or in response to a request to do so from the network node.
1. A method performed in a wireless communication device (WCD) in communication with a network having a network node and a plurality of base stations, the method comprising:
the WCD determining, a cross-correlation between a received downlink signal and a transmitted Position Reference Signal (PRS) for each base station from the plurality of base stations;
the WCD determining, based on the determined cross-correlation, PRS correlation function characteristics, wherein the PRS correlation function characteristics include a reference cell peak of a reference cell and a reference time associated with the reference cell peak; and
the WCD transmitting the PRS correlation function characteristics to the network node.
2. The method according to claim 1 , wherein the reference cell peak is one of the first peak above a predefined threshold, the largest peak above the threshold, and the last peak above the threshold.
3. The method according to claim 1 , wherein the PRS correlation function characteristics further include a reference signal time difference (RSTD) for each neighbor cell relative to the reference cell.
4. The method according to claim 3 , wherein the RSTD indicates a time lag of one of a first peak above a predefined threshold relative to the reference peak, a largest peak above the predefined threshold relative to the reference peak, and a last peak above the threshold relative to the reference peak.
5. The method according to claim 1 , wherein the PRS correlation function characteristics further include a width of each peak above a predefined threshold.
6. The method according to claim 1 , wherein the PRS correlation function characteristics further include a cross-correlation value of each peak above a predefined threshold.
7. The method according to claim 1 , further comprising the WCD receiving a request for location information in response to a determination that a predetermined condition is met, wherein the determining is performed in response to receiving the request.
8. The method according to claim 7 , wherein the predetermined condition specifies that the WCD is configured to support PRS correlation function characteristics feedback.
9. The method according to claim 7 , wherein the predetermined condition specifies that an emergency call is received.
10. The method according to claim 1 , the method further comprising: the WCD receiving, from the network node, assistance data that supports preparation of the PRS correlation function characteristics data.
11. The method according to claim 1 , further comprising the WCD receiving, from the network node, a request for location information if a predetermined condition is met, the WCD transmitting the PRS correlation function characteristics in response to the request.
12. The method according to claim 1 , wherein the received downlink signal is a PRS signal received from one of the base stations from the plurality of base stations, and the transmitted PRS is a predetermined waveform or set of values transmitted from each base station to the WCD and stored on the WCD.
13. A wireless communication device (WCD) configured to communicate with a network having a network node and a plurality of base stations, the WCD comprising:
a processing circuit,
a computer readable medium coupled to the processing circuit, said computer readable medium containing instructions executable by the processing circuit, whereby the WCD is operative to:
determine, a cross-correlation between a received downlink signal and a transmitted Position Reference Signal (PRS) for each base station from the plurality of base stations;
determine, based on the determined cross-correlation, PRS correlation function characteristics, wherein the PRS correlation function characteristics include a reference cell peak of a reference cell and a reference time associated with the reference cell peak; and
transmit the PRS correlation function characteristics to the network node.
14. The WCD according to claim 13 , wherein the reference cell peak is one of the first peak above a predefined threshold, the largest peak above the threshold, and the last peak above the threshold.
15. The WCD according to claim 13 , wherein the PRS correlation function characteristics further include a reference signal time difference (RSTD) for each neighbor cell relative to the reference cell.
16. The WCD according to claim 15 , wherein the RSTD indicates a time lag of one of a first peak above a predefined threshold relative to the reference peak, a largest peak above the predefined threshold relative to the reference peak, and a last peak above the threshold relative to the reference peak.
17. The WCD according to claim 13 , wherein the PRS correlation function characteristics further include a width of each peak above a predefined threshold.
18. The WCD according to claim 13 , wherein the PRS correlation function characteristics further include a cross-correlation value of each peak above a predefined threshold.
19. The WCD according to claim 13 , wherein the WCD is further operative to receive a request for location information in response to a determination that a predetermined condition is met, wherein the determining is performed in response to receiving the request.
20. The WCD according to claim 19 , wherein the predetermined condition specifies that the WCD is configured to support PRS correlation function characteristics feedback.
21. The WCD according to claim 19 , wherein the predetermined condition specifies that an emergency call is received.
22. The WCD according to claim 13 , the WCD further comprising: the WCD receiving, from the network node, assistance data that supports preparation of the PRS correlation function characteristics data.
23. The WCD according to claim 13 , wherein the WCD is further operative to receive, from the network node, a request for location information if a predetermined condition is met, the WCD transmitting the PRS correlation function characteristics in response to the request.
24. The WCD according to claim 13 , wherein the received downlink signal is a PRS signal received from one of the base stations from the plurality of base stations, and the transmitted PRS is a predetermined waveform or set of values transmitted from each base station to the WCD and stored on the WCD.