POLLED TIME-OF-FLIGHT RESPONSE

• US 20140204793A1
• Filed: 06/27/2013
• Published: 07/24/2014
• Est. Priority Date: 01/23/2013
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Ben-Haim, Shani, Amizur, Yuval, Segev, Jonathan
• Granted Patent: US 9,125,168 B2
• Time in Patent Office: Days
• US Class Current: 370/253
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• 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: H04L 7/0033 Correction by delay
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Embodiments of a communication station and method for time-of-flight (ToF) location determination in a wireless network are generally described herein. In some embodiments, a responding communication station receives a ToF measurement request. The responding communication station transmits an acknowledgment of the ToF measurement request. The responding communication station also transmits a response to the ToF measurement request that includes an indication of a time period for an initiating communication station to poll the responding communication station for a ToF result.

Claims

1. A method performed by a communication station for time-of-flight (ToF) calculation, the method comprising:

receiving, from an initiating communication station, a ToF measurement request/poll action frame, comprising a measurement request bit indicating to perform a measurement, at a first time;

transmitting, to the initiating communication station, an acknowledgment of the ToF measurement request/poll action frame at a second time; and

transmitting, to the initiating communication station, a response to the ToF measurement request/poll action frame, requesting to perform the measurement, comprising an indication of a time period for the initiating communication station to poll a responding communication station for a ToF result.

2. The method of claim 1 and further comprising:

receiving, from the initiating communication station, a measurement request/poll action frame comprising a measurement poll bit indicating to poll for the ToF result; and

transmitting the ToF result to the initiating communication station.

3. The method of claim 1 and further comprising:

determining a difference between the first time and the second time as the ToF result.

4. The method of claim 1 and further comprising:

transmitting, to the initiating communication station, a time for the initiating communication station to wait prior to polling the responding communication station; and

transmitting, to the initiating communication station, a time that the responding communication station buffers the ToF result.

5. The method of claim 1 wherein the first time is t2 and the second time is t3, the method further comprising:

the initiating communication station transmitting the ToF measurement request/poll action frame at a time t1;

the initiating communication station receiving the acknowledgment of the ToF measurement request/poll action frame at a time t4; and

calculating ToF between the initiating communication station and the responding communication station in response to (t4−

t1)−

(t3−

t2).

6. The method of claim 5 and further comprising calculating a distance between the initiating communication station and the responding communication station in response to ToF/(2*speed_of_light).

7. The method of claim 5 and further comprising:

the initiating communication station removing multipath signal effects from received signals.

8. The method of claim 1 and further comprising receiving, from the initiating communication station an acknowledgment of the response to the ToF measurement request.

9. The method of claim 1 wherein the initiating communication station is a mobile wireless communicator.

10. The method of claim 1 wherein the responding communication station is an access point.

11. A wireless communication station to operate as an initiating communication station for time-of-flight (ToF) determination, the initiating communication station to:

transmit, to a responding communication station, a second ToF request subsequent to a first ToF measurement request/poll action frame, the first ToF measurement request/poll action frame comprising a first measurement request bit, indicating to perform a measurement, and the second ToF request comprising a second measurement request bit and a polling request bit, indicating to perform the measurement and to poll for previous ToF result, respectively;

receive, from the responding communication station, an acknowledgment of the second ToF measurement request/poll action frame; and

receive, from the responding communication station and in response to the polling request bit, a ToF result comprising a time difference between a time that the responding communication station received the first ToF measurement request/poll action frame and a time that the responding communication station transmitted an acknowledgment to the first ToF measurement request/poll action frame, the ToF result further comprising an indication of a time period for the initiating communication station to poll the responding station for a ToF result resulting from the second ToF measurement request/poll action frame.

12. The initiating communication station of claim 11 wherein the initiating communication station is part of a wireless communication network that further comprises the responding communication station, the responding communication station to:

receive, from the initiating communication station, the second ToF measurement request/poll action frame subsequent to the first ToF measurement request/poll action frame;

transmit, to the initiating communication station, the acknowledgment of the second ToF measurement request/poll action frame; and

transmit, to the initiating communication station, the ToF result.

13. The initiating communication station of claim 12 wherein the wireless communication network further comprises a plurality of responding communication stations.

14. The initiating communication station of claim 13 wherein the initiating communication station is further configured to determine a ToF with each of the plurality of responding communication stations in response to a respective indication of a time period for the initiating communication station to poll the respective responding communication station.

15. A wireless communication station configured to operate as a mobile communication device for time-of-flight (ToF) determination, the device comprising:

an antenna;

physical layer circuitry coupled to the antenna and configured to transmit a plurality of ToF measurement request/poll action frames to an access point, a first ToF measurement request/poll action frame comprising a measurement request bit indicating to perform a measurement and subsequent ToF measurement request/poll action frames comprising the measurement request bit indicating to perform the measurement and a poll request bit indicating to perform a poll of a previous ToF result, each of the plurality of ToF measurement request/poll action frames transmitted at an associated time; and

processing circuitry configured to perform ToF calculations in response to a ToF frame exchange sequence, wherein, during the ToF frame exchange sequence;

the physical layer circuitry is configured to receive an acknowledgment associated with each ToF measurement request/poll action frame and a ToF result comprising a first time difference that is a difference between a time the access point received the ToF measurement request/poll action frame and the associated acknowledgment is transmitted, the ToF result further comprising a time period during which the mobile communication device can poll the access point for the ToF result, and

the processing circuitry is configured to determine a second time difference that is a difference between the associated time a particular ToF measurement request/poll action frame is transmitted and a time of receipt of an associated acknowledgment, the processing circuitry is further configured to determine a location of the mobile communication station in relation to the access point in response to a different between the first time difference and the second time difference.

16. The device of claim 15 wherein the processing circuitry is further configured to remove multipath signal effects from received signals.

17. A non-transitory computer-readable storage medium that stores instructions for execution by processing circuitry of a mobile wireless communication station to perform operations to determine a location with respect to a stationary wireless communication station using time-of-flight (ToF) results, the operations to configure the mobile wireless communication station to:

transmit a ToF measurement request/poll action frame;

receive an acknowledgment of the ToF measurement request/poll action frame;

receive a ToF response comprising an indication of a time period to poll the stationary wireless communication station for a ToF result; and

poll the stationary wireless communication station for the ToF result during the time period.

18. The non-transitory computer-readable storage medium of claim 17 wherein the operations further configure the stationary wireless communication station to:

receive the ToF measurement request/poll action frame with a poll request bit set to indicate to poll for the ToF result;

transmit the acknowledgment of the ToF measurement request/poll action frame; and

transmit the ToF result in response to the poll request bit, the ToF result comprising an indication of a time period for the mobile wireless communication station to transmit the poll request.