Systems and methods of offloaded positioning for determining location of WLAN nodes

Patent metadata

Field	Value
Publication number	US-9332523-B2
Application number	US-201414272844-A
Country	US
Kind code	B2
Filing date	May 8, 2014
Priority date	May 10, 2013
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

This disclosure includes systems and methods for determining the location of each of a plurality of STAs of a WLAN where an AP measures the round-trip time (RTT) and the angle of arrival (AOA) to each STA from implicit packet exchange, such as data frame and ACK frame. The AP may then report the RTT and AOA measurements to each STA using a dedicated beacon information element (IE) which multicasts RTT and AOA measurements to the STAs. By employing an additional parameter, namely, angle of arrival AOA, a single AP may compute the two-dimensional location of each associated STA. Further, another beacon IE may multicast mapping of the AIDs to MAC addresses so that the associated STAs can understand such mapping for STAs in a network so that one STA may know the location of other STAs. Encryption may be employed to achieve privacy.

First claim

What is claimed is:

1. In a wireless communications network having an access point and at least one station associated with the access point, a method of determining a location of the at least one station comprising:
determining with the access point a round trip time (RTT) of a wireless transmission including a first implicit frame sent from the access point to the at least one station and a second implicit flame sent from the at least one station to the access point;
determining with the access point an angle of arrival (AOA) of a wireless transmission including a first implicit frame sent from the at least one station to the access point; and
multicasting with the access point location information including the determined RTT and the determined AOA for the at least one station.

2. The method of claim 1 , further comprising determining with the access point RTT and AOA for each of a plurality of stations, wherein multicasting the location information includes the determined RTT and the determined AOA for each of the plurality of stations.

3. The method of claim 2 , wherein the determined RTT and the determined AOA for each of the plurality of stations is correlated with a network address identifier (AID).

4. The method of claim 3 , further comprising multicasting with the access point mapping information that associates the AID for each of the plurality of stations with an identification that is independent of the wireless communications network.

5. The method of claim 4 , further comprising encrypting the mapping information prior to the multicasting.

6. The method of claim 5 , further comprising transmitting a key for. decrypting the mapping information with the access point to a subset of the plurality of stations that have elected to participate in location determination.

7. The method of claim 1 , wherein determining the RTI comprises:
recording a departure time for the first implicit frame;
recording an arrival time for the second implicit frame; and
determining the RTT based at least in part on the departure time and the arrival time.

8. The method of claim 7 , wherein determining the RTT further comprises compensating for a short interframe space (SIFS) between the first implicit flame and the second implicit frame.

9. The method of claim 1 , wherein multicasting location information comprises including the determined RTT and the determined AOA into a beacon transmission.

10. In a wireless communications network having an access point and a station associated with the access point, a method of determining a location of the station comprising:
receiving with the station at least a first implicit frame transmitted by the access point;
transmitting with the station at least a second implicit frame to the access point;
receiving with the station a multicast from the access point having location information including a round trip time (RTT) and an angle of arrival (AOA) determined based at least in part on the implicit flames; and
determining at the station the location of the station based at least in part on the multicast location information.

11. The method of claim 10 , wherein the multicast location information received from the access point includes a determined RTT and a determined AOA for at least one additional station, further comprising determining at the station a location of the at least one additional station based at least in part on the determined RTT and the determined AOA.

12. The method of claim 11 , further comprising determining a position of the station relative to the at least one additional station based at least in part on the determined location of the station and the determined location of the at least one additional station.

13. The method of claim 11 , wherein the determined RTT and the determined AOA for the at least one additional station is correlated with a network address identifier (AID).

14. The method of claim 13 , further comprising receiving with the station a multicast from the access point having mapping information that associates the AID for the at least one additional station with an identification that is independent of the wireless communications network.

15. The method of claim 14 , wherein the mapping information multicast by the access point is encrypted, further comprising receiving with the station a key for decrypting the mapping information from the access point transmitted to stations that have elected to participate in location determination and using the key to decrypt the mapping information.

16. A wireless communications device for determining a location of a station in a wireless local area network (WLAN) comprising a WLAN module and a location manager, wherein the location manager is configured to:
determine a round trip time (RTT) of a wireless transmission including a first implicit flame sent from the wireless communications device to a first station and a second implicit frame sent from the first station to the wireless communications device;
determine an angle of arrival (AOA) of a wireless transmission including a first implicit frame sent from the first station to the wireless communications device; and
multicast location information with the WLAN module including the determined RTT and the determined AOA for the first station.

17. The wireless communications device of claim 16 , wherein the location manager is further configured to determine RTT and AOA for each of a plurality of stations and wherein multicasting location information includes the determined RTT and the determined AOA for each of the plurality of stations.

18. The wireless communications device of claim 17 , wherein the determined RTT and the determined AOA for each of the plurality of stations is con elated with a network address identifier (AID).

19. The wireless communications device of claim 18 , wherein the location manager is further configured to multicast with the WLAN module mapping information that associates the AID for each of the plurality of stations with an identification that is independent of the wireless communications network.

20. The wireless communications device of claim 19 , wherein the mapping information is encrypted.

21. The wireless communications device of claim 20 , wherein the location manager is further configured to transmit with the WLAN module a key for decrypting the mapping information to a subset of the plurality of stations that have elected to participate in location determination.

22. The wireless communications device of claim 16 , wherein the location manager is configured to determine the RTT by:
recording a departure time for the first implicit frame;
recording an arrival time for the second implicit frame; and
determining the RTT based at least in part on the departure time and the arrival time.

23. The wireless communications device of claim 22 , wherein the location manager is further configured to determine the RTT by compensating for a short interframe space (SIFS) between the first implicit flame and the second implicit flame.

24. The wireless communications device of claim 16 , wherein the location manager is configured to multicast location information with the WLAN module by including the determined RTT and the determined AOA into a beacon transmission.

25. A wireless communications device for determining a location of the wireless communications device in a wireless local area network (WLAN) managed by an access poin

Assignees

• Qualcomm Inc
• Qualcomm Inc

Inventors

• Zhang Xiaoxin
• Aldana Carlos Horacio
• Homchaudhuri Sandip
• Cho James Simon

Classifications

• H04W64/00 Primary

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

• G01S5/0205

  Details · CPC title

• H04W64/003 Primary

  locating network equipment · CPC title