Pedestrian positioning via vehicle collaboration
Disclosed are techniques for using ranging signals to determine a position of a pedestrian user equipment (P-UE). In an aspect, a UE receives a plurality of ranging signals transmitted by one or more UEs, measures one or more properties of each of the plurality of ranging signals, and calculates an estimate of the position of the P-UE based on the one or more properties of each of the plurality of ranging signals. In an aspect, the P-UE transmits a plurality of ranging signals, receives a first message and a second message from first and second vehicle UEs (V-UEs), the first and second messages including first and second estimated positions of the P-UE and associated first and second confidences, and calculates an estimate of the position of the P-UE based on the first estimated position, the first confidence, the second estimated position, the second confidence, or a combination thereof.
1. A method for using ranging signals to determine a position of a pedestrian user equipment (P-UE), comprising:
receiving, at a first user equipment (UE), a plurality of ranging signals transmitted by at least one moving vehicular UE (V-UE) from a plurality of positions;
measuring, by the first UE, one or more properties of each of the plurality of ranging signals; and
calculating, by the first UE, an estimate of the position of the P-UE based on the one or more properties of each of the plurality of ranging signals.
2. The method of claim 1 , wherein the one or more properties of each of the plurality of ranging signals comprise a time of arrival (ToA) of each of the plurality of ranging signals, an angle-of-arrival (AoA) of each of the plurality of ranging signals, or any combination thereof.
3. The method of claim 2 , wherein the ToA of each of the plurality of ranging signals is based on a local clock time of the first UE.
4. The method of claim 1 , further comprising:
transmitting, by the first UE, the estimate of the position of the P-UE to a second UE.
5. The method of claim 4 , further comprising:
calculating, by the first UE, a confidence level in the estimate of the position of the P-UE.
6. The method of claim 5 , wherein the confidence level is based on AoAs of the plurality of ranging signals, wherein the confidence level is higher based on larger differences between AoAs of the plurality of ranging signals.
7. The method of claim 5 , wherein transmitting the estimate of the position of the P-UE to the second UE further comprises transmitting, by the first UE, the confidence level in the estimate of the position of the P-UE to the second UE.
8. The method of claim 4 , wherein the first UE comprises a vehicle UE (V-UE) and the second UE comprises the P-UE.
9. The method of claim 8 , wherein the calculation of the estimate of the position of the P-UE is further based on a known position of the first UE.
10. The method of claim 4 , wherein the first UE comprises a first vehicle UE (V-UE) and the second UE comprises a second V-UE.
11. The method of claim 10 , wherein the first V-UE transmits the estimate of the position of the P-UE to the second V-UE in a Basic Safety Message.
12. The method of claim 4 , wherein the first UE comprises the P-UE and the second UE comprises a V-UE.
13. The method of claim 1 , wherein each of the plurality of ranging signals comprises a Zadoff-Chu sequence.
14. The method of claim 1 , wherein each of the plurality of ranging signals encodes an identifier of a UE by which the ranging signal was transmitted.
15. The method of claim 1 , wherein the plurality of ranging signals is transmitted periodically in consecutive resource pools.
16. The method of claim 1 , wherein a position of the P-UE is considered to be constant when calculating the estimate of the position of the P-UE.
17. The method of claim 1 , wherein the at least one V-UE comprises a single V-UE.
18. The method of claim 1 , wherein the at least one V-UE comprises a plurality of V-UEs.
19. The method of claim 18 , wherein the first UE calculates a plurality of estimates of the position of the P-UE based on properties of each of the plurality of ranging signals received from the plurality of V-UEs, and wherein calculating the estimate of the position of the P-UE comprises calculating the estimate of the position of the P-UE by combining the plurality of estimates of the position of the P-UE.
20. A method for determining a position of a pedestrian user equipment (P-UE), comprising:
transmitting, by the P-UE, a plurality of ranging signals in a plurality of ranging resource sets;
receiving, at the P-UE, a first message from a first vehicle user equipment (V-UE), the first message including a first estimated position of the P-UE and a first indicator of confidence of the first estimated position;
receiving, at the P-UE, a second message from a second V-UE, the second message including a second estimated position of the P-UE and a second indicator of confidence of the second estimated position; and
calculating, by the P-UE, an estimate of the position of the P-UE based on the first estimated position, the first indicator, the second estimated position, the second indicator, or a combination thereof.
21. The method of claim 20 , further comprising transmitting a basic safety message (BSM) including the estimate of the position of the P-UE.
22. The method of claim 20 , wherein the plurality of ranging signals includes at least a first set of ranging signals transmitted using a first set of transmission resources for the P-UE and a second set of ranging signals transmitted using a second set of transmission resources for the P-UE.
23. The method of claim 20 , further comprising transmitting an identifier of the P-UE, a mode of the P-UE, or both.
24. The method of claim 23 , wherein each of the plurality of ranging signals comprises a Zadoff-Chu sequence having a sequence identifier, and wherein the sequence identifier is the identifier of the P-UE.
25. The method of claim 24 , wherein the Zadoff-Chu sequence includes an indication of the mode of the P-UE.
26. The method of claim 20 , wherein the calculating comprises:
adopting, by the P-UE, the first estimated position or the second estimated position based on which of the first indicator or the second indicator indicates a higher confidence level.
27. The method of claim 20 , wherein the calculating comprises:
setting, by the P-UE, the estimate of the position of the P-UE as an average of the first estimated position and the second estimated position.
28. The method of claim 20 , wherein a position of the P-UE is considered to be constant when calculating the estimate of the position of the P-UE.
29. An apparatus for using ranging signals to determine a position of a pedestrian user equipment (P-UE), comprising:
a transceiver of a first user equipment (UE) configured to:
receive a plurality of ranging signals transmitted by at least one moving vehicular UE (V-UE) from a plurality of positions; and
measure one or more properties of each of the plurality of ranging signals; and
at least one processor of the first UE configured to calculate an estimate of the position of the P-UE based on the one or more properties of each of the plurality of ranging signals.
30. An apparatus for determining a position of a pedestrian user equipment (P-UE), comprising:
a transceiver of the P-UE configured to:
transmit a plurality of ranging signals in a plurality of ranging resource sets;
receive a first message from a first vehicle user equipment (V-UE), the first message including a first estimated position of the P-UE and a first indicator of confidence of the first estimated position; and
receive a second message from a second V-UE, the second message including a second estimated position of the P-UE and a second indicator of confidence of the second estimated position; and
at least one processor of the P-UE configured to calculate an estimate of the position of the P-UE based on the first estimated position, the first indicator, the second estimated position, the second indicator, or a combination thereof.