Distributed positioning mechanism for wireless communication devices

• US 8,909,244 B2
• Filed: 06/28/2011
• Issued: 12/09/2014
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Curticapean, Florean
• Primary Examiner(s): Cai, Wayne
• Application Number:
  US13/170,353
• Publication Number:
  US 20130005347A1
• Time in Patent Office: 1,260 Days
• Field of Search: 4554561-4566
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0226 Transmitters
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A wireless communication device can determine its position in accordance with a distributed positioning mechanism to minimize bandwidth and power consumption at the wireless communication device. The wireless communication device can detect positioning control messages exchanged between independent pairs of access points in a wireless communication network. The wireless communication device can determine position information associated with each access point of each of the pairs of access points and timing information associated with the pairs of access points based, at least in part, on the detected positioning control messages. The position of the wireless communication device can then be calculated based, at least in part, on the position information and the timing information associated with the pairs of access points.

Claims

1. A method performed by a communication device in a wireless communication network, the method comprising:

detecting a plurality of positioning control messages exchanged between at least two pairs of access points in the wireless communication network;

determining position information associated with each access point of each of the at least two pairs of access points, the position information based, at least in part, on the plurality of positioning control messages;

determining timing information associated with the at least two pairs of access points based, at least in part, on the plurality of positioning control messages; and

determining a current position associated with the communication device of the wireless communication network based, at least in part, on the position information and the timing information.

2. The method of claim 1, wherein said determining the current position associated with the communication device further comprises:

determining whether the plurality of positioning control messages were exchanged between a predetermined number of independent pairs of access points; and

determining the current position associated with the communication device in response to determining that the plurality of positioning control messages were exchanged between the predetermined number of independent pairs of access points.

3. The method of claim 1, wherein said determining the current position associated with the communication device further comprises:

determining whether the position information and the timing information associated with at least a predetermined number of independent pairs of access points are available; and

determining the current position associated with the communication device in response to determining that the position information and the timing information associated with at least the predetermined number of independent pairs of access points are available.

4. The method of claim 1, wherein determining the position information associated with each access point comprises obtaining a location of each access point from one of the plurality of positioning control messages.

5. The method of claim 1, wherein said determining the timing information associated with the at least two pairs of access points comprises:

for each pair of access points;

determining time instants at which a positioning request message and a corresponding positioning response message exchanged by the pair of access points were received at the communication device, wherein the plurality of positioning control messages comprise the positioning request message and the corresponding positioning response message;

determining time instants at which the positioning request message and the corresponding positioning response message were transmitted by the pair of access points; and

determining a transit time associated with the pair of access points based on the time instants at which the positioning request message and the corresponding positioning response message were received at the communication device and based on the time instants at which the positioning request message and the corresponding positioning response message were transmitted by the pair of access points.

6. The method of claim 1, wherein said detecting the plurality of positioning control messages exchanged between the at least two pairs of access points comprises one of:

detecting the plurality of positioning control messages on a predetermined positioning control channel;

or

scanning at least a predetermined subset of a plurality of communication channels associated with the wireless communication network.

7. The method of claim 6, wherein said scanning at least the predetermined subset of the plurality of communication channels comprises at least one member of a group comprising:

switching from a first of the predetermined subset of the plurality of communication channels to a second of the predetermined subset of the plurality of communication channels in accordance with a channel switching sequence,

switching from the first of the predetermined subset of the plurality of communication channels to the second of the predetermined subset of the plurality of communication channels after a switching time interval, and

switching from the first of the predetermined subset of the plurality of communication channels to the second of the predetermined subset of the plurality of communication channels at one or more switching time instants.

8. The method of claim 1, wherein said detecting the plurality of positioning control messages comprises:

for each pair of access points;

detecting a positioning request message transmitted from a first access point of the pair of access points; and

detecting a positioning response message, corresponding to the positioning request message, transmitted from a second access point of the pair of access points.

9. The method of claim 8,

wherein the positioning request message comprises an indication of a first position of the first access point that transmitted the positioning request message, a sequence number associated with the positioning request message, and a first propagation time interval associated with the first access point, and

wherein the positioning response message comprises an indication of a second position of the second access point that transmitted the positioning response message, the sequence number associated with the positioning request message, and a second propagation time interval associated with the second access point.

10. The method of claim 9,

wherein the first propagation time interval comprises a time interval associated with a first transmitter of the first access point;

and

wherein the second propagation time interval comprises a time interval associated with a second transmitter of the second access point, a time interval associated with a receiver of the second access point, a time interval associated with a processor of the second access point, and an external propagation time interval between the first access point transmitting the positioning request message and the receiver of the second access point receiving the positioning request message.

11. The method of claim 1,

wherein said determining the timing information associated with the at least two pairs of access points comprises, for each pair of access points:

detecting a first set of positioning control messages exchanged between the pair of access points and a second set of positioning control messages exchanged between the pair of access points;

determining timing information associated with each of the first set of positioning control messages and the second set of positioning control messages; and

averaging the timing information associated with each of the first set of positioning control messages and the second set of positioning control messages across a predetermined time interval to yield an average timing information associated with the pair of access points; and

wherein said determining the current position associated with the communication device comprises;

determining the current position associated with the communication device based, at least in part, on the position information and the average timing information associated with the at least two pairs of access points.

12. A communication device comprising:

a processor;

a network interface in communication with the processor; and

a memory storing instructions, which when executed by the processor, cause the communication device to;

detect a plurality of positioning control messages exchanged between at least two pairs of access points in a wireless communication network;

determine position information associated with each access point of each of the at least two pairs of access points, the position information based, at least in part, on the plurality of positioning control messages;

determine timing information associated with the at least two pairs of access points based, at least in part, on the plurality of positioning control messages; and

determine current position associated with the communication device of the wireless communication network based, at least in part, on the position information and the timing information.

13. The communication device of claim 12, wherein the instructions, which when executed by the processor, cause the communication device to:

determine whether the position information and the timing information associated with at least a predetermined number of independent pairs of access points are available; and

determine the current position associated with the communication device in response to determining that the position information and the timing information associated with at least the predetermined number of independent pairs of access points are available.

14. The communication device of claim 12, wherein the instructions, which when executed by the processor, cause the communication device to:

detect the plurality of positioning control messages on a predetermined positioning control channel;

or

scan at least a predetermined subset of a plurality of communication channels associated with the wireless communication network.

15. The communication device of claim 14, wherein the instructions, which when executed by the processor, further cause the communication device to:

switch from a first of the predetermined subset of the plurality of communication channels to a second of the predetermined subset of the plurality of communication channels in accordance with a channel switching sequence,

switch from the first of the predetermined subset of the plurality of communication channels to the second of the predetermined subset of the plurality of communication channels after a switching time interval, or

switch from the first of the predetermined subset of the plurality of communication channels to the second of the predetermined subset of the plurality of communication channels at one or more switching time instants.

16. A non-transitory machine-readable medium having instructions stored therein, which when executed by one or more processors causes the one or more processors to perform operations that comprise:

detecting a plurality of positioning control messages exchanged between at least two pairs of access points in a wireless communication network;

determining position information associated with each access point of each of the at least two pairs of access points based, at least in part, on the plurality of positioning control messages;

determining timing information associated with the at least two pairs of access points based, at least in part, on the plurality of positioning control messages; and

determining a current position associated with a communication device of the wireless communication network based, at least in part, on the position information and the timing information.

17. The non-transitory machine-readable medium of claim 16, wherein determining the current position associated with the communication device further comprises:

determining whether the position information and the timing information associated with at least a predetermined number of independent pairs of access points are available; and

determining the current position associated with the communication device in response to determining that the position information and the timing information associated with at least the predetermined number of independent pairs of access points are available.

18. The non-transitory machine-readable medium of claim 16, wherein determining the timing information associated with the at least two pairs of access points comprises:

for each pair of access points;

determining time instants at which a positioning request message and a corresponding positioning response message exchanged by the pair of access points were received at the communication device, wherein the plurality of positioning control messages comprise the positioning request message and the corresponding positioning response message;

determining time instants at which the positioning request message and the corresponding positioning response message were transmitted by the pair of access points; and

determining a transit time associated with the pair of access points based on the time instants at which the positioning request message and the corresponding positioning response message were received at the communication device and based on the time instants at which the positioning request message and the corresponding positioning response message were transmitted by the pair of access points.

19. The non-transitory machine-readable medium of claim 16, wherein detecting the plurality of positioning control messages comprises one of:

detecting the plurality of positioning control messages on a predetermined positioning control channel;

or

scanning at least a predetermined subset of a plurality of communication channels associated with the wireless communication network.

20. The non-transitory machine-readable medium of claim 16, wherein detecting the plurality of positioning control messages exchanged between the at least two pairs of access points comprises:

for each pair of access points;

detecting a positioning request message from a first access point of the pair of access points, wherein the positioning request message comprises an indication of a position of the first access point that transmitted the positioning request message, a sequence number associated with the positioning request message, and a first propagation time interval associated with the first access point; and

detecting a positioning response message corresponding to the positioning request message from a second access point of the pair of access points, wherein the positioning response message comprises an indication of a position of the second access point that transmitted the positioning response message, the sequence number associated with the positioning request message, and a second propagation time interval associated with the second access point.