Method for determining location of wireless devices based on information within messages received from other network devices

• US 9,288,625 B2
• Filed: 06/30/2014
• Issued: 03/15/2016
• Est. Priority Date: 06/30/2014
• Status: Active Grant

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Inventors: Lindskog, Erik, Wan, Hong
• Primary Examiner(s): Mushambo, Martin
• Application Number:
  US14/319,476
• Publication Number:
  US 20150382143A1
• Time in Patent Office: 624 Days
• Field of Search: 455/456, 455/466
• US Class Current: 1/1
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds

Abstract

A method for determining the location of a client device in a wireless network having at least a first and a second other network devices each with a known location is disclosed. The first other network device and the second other network device each transmit to the other two messages, and each acknowledges the first message sent by the other. The client device receives these messages, the acknowledgement messages, and respective timing information indicating the actual time when the message and the acknowledgement message were processed by the first and the second other network devices. The client device utilizes the difference between the actual processing times to determine its location. This method allows the location determination to be independent of the accuracy of the time of flight between the first other network device and the second other network device.

Claims

1. A method for determining a location of a client device in a wireless network including at least a first and second other network devices having known locations, the method comprising:

transmitting from the first other network device a first message to the second other network device;

transmitting from the second other network device a first acknowledgement in response to receiving the first message;

transmitting from the first other network device a second message following the first message to the second other network device;

transmitting from the second other network device a third message to the first other network device;

transmitting from the first other network device a second acknowledgement in response to receiving the third message;

transmitting from the second other network device a fourth message following the third message;

receiving, at the client device from at least one of the first other network device and the second other network device, information agreed upon by the first other network device and the second other network device in response to a pair being formed between the first other network device and the second other network device;

receiving, by the client device, the first message, the first acknowledgement in response to the first message, the second message, the third message, the second acknowledgement in response to the third message, and the fourth message based on the agreed upon information; and

calculating the location of the client device based on information within the first, second third, and fourth messages received from the first and the second other network devices and the known locations of the first and second other network devices.

2. A method for determining a location of a client device in a wireless network including at least a first and second other network devices having known locations, the method comprising:

receiving, from at least one of the first other network device and the second other network device, information agreed upon by the first other network device and the second other network device in response to a pair being formed between the first other network device and the second other network device;

receiving from the first other network device a first message based on the agreed upon information;

receiving from the second other network device a first acknowledgement in response to receiving the first message based on the agreed upon information;

receiving from the first other network device a second message following the first message to the second other network device based on the agreed upon information;

receiving from the second other network device a third message based on the agreed upon information;

receiving from the first other network device a second acknowledgement in response to receiving the third message based on the agreed upon information;

receiving from the second other network device a fourth message following the third message based on the agreed upon information; and

calculating a location of a computing device based on information within the messages received from the first and the second other network devices and known locations of the first other network device and the second other network device.

3. The method according to claim 2, wherein the second message includes an actual time of transmission of the first message and an actual time of reception of the first acknowledgement in response to the first message.

4. The method according claim 2, wherein the fourth message includes an actual transmission time of the third message and an actual reception time of the second acknowledgement in response to the third message.

5. The method according to claim 2, wherein each of the first and second other network devices includes a radio-frequency (RF) section and a digital section where receive circuitry of the RF section is coupled to the digital section by analogue-to-digital conversion (ADC) circuitry and transmit circuitry of the RF section is coupled to the digital section by digital-to-analogue conversion (DAC) circuitry, and wherein an actual time of reception is a time at which a message is processed by the ADC circuitry of a receiving network device and an actual time of transmission is a time at which an acknowledgement of the message is processed by the DAC circuitry of a transmitting network device.

6. The method according to claim 2, wherein the client device is a mobile wireless device and the first and second other network devices are wireless access points on the wireless network.

7. The method of claim 2, wherein the agreed upon information includes one or more of a channel, a periodicity, and a bandwidth used by the first other network device and the second other network device to transmit messages for receipt by the client device.

8. The method of claim 7, further comprising:

determining, by the client device, a channel for receiving one or more of the first message, the first acknowledgement in response to the first message, the second message, the third message, the second acknowledgement in response to the third message, and the fourth message based on the agreed upon information; and

tuning, by the client device, to the channel in response to determining the channel based on the agreed upon information.

9. The method of claim 8, further comprising:

receiving, at the client device from at least one of a third other network device and a fourth other network device, other information agreed upon by the third other network device and the fourth other network device in response to a second pair being formed between the third other network device and the fourth other network device;

tuning, by the client device, to another channel based on the other agreed upon information;

receiving, by the client device based on the other agreed upon information, a fifth message from the third other network device, a third acknowledgement in response to the fifth message from the fourth other network device, a sixth message from the third other network device, a seventh message from the fourth other network device, a fourth acknowledgement in response to the seventh message from the third other network device, and a eighth message from the fourth other network device; and

calculating the location of the client device based on at least information received from the first other network device, the second other network device, the third other network device, and the fourth other network device.

10. The method of claim 2, further comprising:

turning off, by the client device, a receiver at a first time based on the agreed upon information; and

turning on, by the client device, the receiver at a second time based on the agreed upon information,

wherein receiving, by the client device, the first message, the first acknowledgement in response to the first message, the second message, the third message, the second acknowledgement in response to the third message and the fourth message based on the agreed upon information comprises;

receiving, by the client device, the first message, the first acknowledgement in response to the first message, the second message, the third message, the second acknowledgement in response to the third message and the fourth message in response to turning on the receiver at the second time.

11. The method of claim 2, wherein calculating a location of the computing device based on information within the messages received from the first and the second other network devices and known locations of the first other network device and the second other network device comprises:

transmitting, by the client device, the information within the messages received from the first and the second other network devices and the known locations of the first and second other network devices to one of a server, the first other network device, and the second other network device; and

receiving, by the client device, the location from the one of the server, the first other network device, and the second other network device.

12. The method of claim 11, wherein transmitting, by the client device, the information within the messages received from the first and the second other network devices and the known locations of the first and second other network devices to one of a server, the first other network device, and the second other network device comprises:

waiting, by the client device, until a fine timing message (FTM) exchange between the first other network device and the second other network device has completed; and

transmitting, by the client device, the information within the messages received from the first and the second other network devices and the known locations of the first and second other network devices to one of the first other network device and the second other network device in response to the waiting.

13. The method of claim 2, further comprising:

determining, by the client device, that a multipath error exists; and

receiving, by the client device, messages from the first other network device and the second other network device using a different frequency or frequency band in response to determining that the multipath error exists.

14. A computing device, comprising:

a memory; and

a processor coupled to the memory and configured with processor-executable instructiom for performing operations comprising;

receiving, from at least one of a first other network device and a second other network device, information agreed upon by the first other network device and the second other network device in response to a pair being formed between the first other network device and the second other network device;

receiving from the first other network device a first message based on the agreed upon information;

receiving from the second other network device a first acknowledgement in response to receiving the first message based on the agreed upon information;

receiving from the first other network device a second message following the first message to the second other network device based on the agreed upon information;

receiving from the second other network device a third message based on the agreed upon information;

receiving from the first other network device a second acknowledgement in response to receiving the third message based on the agreed upon information

receiving from the second other network device a fourth message following the third message based on the agreed upon information; and

calculating a location of the computing device based on information within the messages received from the first and the second other network devices and known locations of the first other network device and the second other network device.

15. A non-transitory processor-readable storage medium having stored thereon processor-executable instructions configured to cause a processor of a computing device to perform operations comprising:

receiving, from at least one of a first other network device and a second other network device, information agreed upon by the first other network device and the second other network device in response to a pair being formed between the first other network device and the second other network device;

receiving from the first other network device a first message based on the agreed upon information;

receiving from the second other network device a first acknowledgement in response to receiving the first message based on the agreed upon information;

receiving from the first other network device a second message following the first message to the second other network device based on the agreed upon information;

receiving from the second other network device a third message based on the agreed upon information;

receiving from the first other network device a second acknowledgement in response to receiving the third message based on the agreed upon information;

receiving from the second other network device a fourth message following the third message based on the agreed upon information; and

calculating a location of the computing device based on information within the messages received from the first and the second other network devices and known locations of the first other network device and the second other network device.