HYBRID POSITIONING MECHANISM FOR WIRELESS COMMUNICATION DEVICES

• US 20120314587A1
• Filed: 06/07/2011
• Published: 12/13/2012
• Est. Priority Date: 06/07/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm Atheros Incorporated (Qualcomm, Inc.)
• Inventors: Curticapean, Florean
• Granted Patent: US 8,547,870 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: G01S 5/0258 by combining or switching between measurements derived from different systems
• CPC Class Codes: G01S 5/0284 Relative positioning
• 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 hybrid positioning mechanism to minimize bandwidth and power consumption at the wireless communication device. The wireless communication device can detect one or more request messages and one or more corresponding response messages exchanged between a master access point and one or more target access points, and can accordingly determine TDOA information associated with the one or more target access points. The wireless communication device can receive, from the master access point, RTT measurement information determined by the master access point based, at least in part, on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points. The wireless communication device can calculate its position information based, at least in part, on the TDOA information and the RTT measurement information.

Claims

1. A method comprising:

detecting, at a communication device of a wireless communication network, one or more request messages and one or more corresponding response messages exchanged between a master access point of the wireless communication network and one or more target access points of the wireless communication network;

determining, at the communication device, time difference of arrival (TDOA) information based, at least in part, on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points;

receiving, from the master access point, an indication of round-trip time (RTT) measurement information determined by the master access point based, at least in part, on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points; and

calculating position information associated with the communication device based, at least in part, on the TDOA information and the RTT measurement information.

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

receiving, from the master access point, position information associated with the master access point and position information associated with the one or more target access points; and

calculating the position information associated with the communication device based, at least in part, on the TDOA information, the RTT measurement information, the position information associated with the master access point, and the position information associated with the one or more target access points.

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

determining position information associated with the master access point, position information associated with the one or more target access points, propagation time intervals associated with the master access point, propagation time intervals associated with the one or more target access points, and propagation time intervals associated with the communication device; and

calculating the position information associated with the communication device based on the TDOA information, the RTT measurement information, the position information associated with the master access point, the position information associated with the one or more target access points, the propagation time intervals associated with the master access point, the propagation time intervals associated with the one or more target access points, and the propagation time intervals associated with the communication device.

4. The method of claim 3,

wherein the propagation time intervals associated with a first target access point of the one or more target access points comprise a time interval associated with a transmitter unit of the first target access point, a time interval associated with a receiver unit of the first target access point, a time interval associated with one or more processing units of the first target access point, and an external propagation time interval between the master access point and the first target access point;

and

wherein the propagation time intervals associated with the master access point comprise a time interval associated with a transmitter unit of the master access point and a time interval associated with a receiver unit of the master access point.

5. The method of claim 1, wherein said calculating the position information associated with the communication device further comprises:

determining whether the TDOA information and the RTT measurement information associated with a predetermined number of target access points are available; and

calculating the position information associated with the communication device in response to determining that the TDOA information and the RTT measurement information associated with the predetermined number of target access points are available.

6. The method of claim 1, further comprising:

detecting the master access point within a predetermined communication range of the communication device;

receiving, from the master access point, an indication of the one or more target access points associated with the master access point;

identifying at least a subset of the one or more target access points that are within the predetermined communication range of the communication device; and

transmitting an indication to the master access point to initiate an RTT measurement sequence to determine the RTT measurement information associated with the subset of the one or more target access points that are within the predetermined communication range of the communication device.

7. The method of claim 1, wherein said receiving the indication of the RTT measurement information determined by the master access point comprises one of

receiving, from the master access point, the RTT measurement information associated with the one or more target access points in one or more corresponding RTT measurement control messages;

or

receiving, from the master access point, the RTT measurement information associated with the one or more target access points in a beacon message associated with the master access point.

8. The method of claim 1, further comprising:

determining, at the communication device, to calculate the position information associated with the communication device; and

in response to said determining to calculate the position information associated with the communication device, providing a trigger message from the communication device to the master access point to cause the master access point to transmit the one or more request messages to the one or more target access points and to determine the RTT measurement information associated with the one or more target access points based on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points.

9. The method of claim 1, further comprising:

receiving, from the master access point, a control message that indicates a start of an RTT measurement sequence associated with a first target access point of the one or more target access points; and

in response to receiving the control message, determining the TDOA information associated with the first target access point based on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points.

10. The method of claim 9, wherein the control message comprises at least one of an identifier of the first target access point, an identifier of the master access point, a communication channel for subsequent transmission of the request message to the first target access point, and a time instant at which subsequent transmission of the request message to the first target access point will be initiated.

11. The method of claim 1, further comprising:

receiving, from the master access point, an indication of one or more communication channels of the wireless communication network via which the one or more request messages and the one or more corresponding response messages are to be exchanged; and

listening on the one or more communication channels of the wireless communication network for said detecting the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points and for said determining the TDOA information.

12. The method of claim 1, further comprising:

receiving, from the master access point, a communication schedule in accordance with which the one or more request messages will be transmitted from the master access point and to the one or more target access points; and

determining whether to switch to an inactive power mode based, at least in part, on the communication schedule in accordance with which the one or more request messages will be transmitted from the master access point and to the one or more target access points.

13. A communication device comprising:

a processor;

a network interface coupled with the processor; and

a positioning unit coupled with the processor and with the network interface, the positioning unit operable to;

detect one or more request messages and one or more corresponding response messages exchanged between a master access point of a wireless communication network and one or more target access points of the wireless communication network;

determine time difference of arrival (TDOA) information based, at least in part, on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points;

receive, from the master access point, an indication of round-trip time (RTT) measurement information determined by the master access point based, at least in part, on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points; and

calculate position information associated with the communication device based, at least in part, on the TDOA information and the RTT measurement information.

14. The communication device of claim 13, wherein the positioning unit operable to calculate the position information associated with the communication device further comprises the positioning unit operable to:

determine whether the TDOA information and the RTT measurement information associated with a predetermined number of target access points are available; and

calculate the position information associated with the communication device in response to the positioning unit determining that the TDOA information and the RTT measurement information associated with the predetermined number of target access points are available.

15. The communication device of claim 13, wherein the positioning unit is further operable to:

determine to calculate the position information associated with the communication device;

detect the master access point within a predetermined communication range of the communication device;

receive, from the master access point, an indication of the one or more target access points associated with the master access point;

identify at least a subset of the one or more target access points that are within the predetermined communication range of the communication device; and

in response to the positioning unit determining to calculate the position information associated with the communication device, provide a trigger message to the master access point to cause the master access point to initiate an RTT measurement sequence to determine the RTT measurement information associated with the subset of the one or more target access points that are within the predetermined communication range of the communication device.

16. The communication device of claim 13, wherein the positioning unit is further operable to:

receive, from the master access point, a control message that indicates a start of an RTT measurement sequence associated with a first target access point of the one or more target access points, wherein the control message comprises at least one of an identifier of the first target access point, an identifier of the master access point, a communication channel for subsequent transmission of the request message to the first target access point, and a time instant at which subsequent transmission of the request message to the first target access point will be initiated; and

in response to the positioning unit receiving the control message, determine the TDOA information associated with the first target access point based on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points.

17. One or more machine-readable storage media having instructions stored therein, which when executed by a one or more processors causes the one or more processors to perform operations that comprise:

detecting, at a communication device of a wireless communication network, one or more request messages and one or more corresponding response messages exchanged between a master access point of the wireless communication network and one or more target access points of the wireless communication network;

determining time difference of arrival (TDOA) information based, at least in part, on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points;

receiving, from the master access point, an indication of round-trip time (RTT) measurement information determined by the master access point based, at least in part, on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points; and

calculating position information associated with the communication device based, at least in part, on the TDOA information and the RTT measurement information.

18. The machine-readable storage media of claim 17, wherein the operations further comprise:

detecting the master access point within a predetermined communication range of the communication device;

receiving, from the master access point, an indication of the one or more target access points associated with the master access point;

identifying at least a subset of the one or more target access points that are within the predetermined communication range of the communication device; and

transmitting an indication to the master access point to initiate an RTT measurement sequence to determine the RTT measurement information associated with the subset of the one or more target access points that are within the predetermined communication range of the communication device.

19. The machine-readable storage media of claim 17, wherein the operations further comprise:

determining to calculate the position information associated with the communication device; and

in response to said operation of determining to calculate the position information associated with the communication device, providing a trigger message to the master access point to cause the master access point to transmit the one or more request messages to the one or more target access points and to determine the RTT measurement information associated with the one or more target access points based on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points.

20. The machine-readable storage media of claim 17, wherein the operations further comprise:

receiving, from the master access point, a control message that indicates a start of an RTT measurement sequence associated with a first target access point of the one or more target access points, wherein the control message comprises at least one of an identifier of the first target access point, an identifier of the master access point, a communication channel for subsequent transmission of the request message to the first target access point, and a time instant at which subsequent transmission of the request message to the first target access point will be initiated; and

in response to receiving the control message, determining the TDOA information associated with the first target access point based on the one or more request messages and the one or more corresponding response messages exchanged between the master access point and the one or more target access points.