Method for determining location of wireless devices
First Claim
1. A method for determining the location of a client device in a wireless network including the client device and at least one other network device having a known location, the method comprising:
- determining a RF delay of the client device by performing, at the client device, a transmission-to-self calibration;
receiving, at the client device, a first message transmitted by the other network device to the client device;
transmitting, from the client device, an acknowledgement message to the other network device in response to receiving the first message;
receiving, at the client device, a second message transmitted by the other network device to the client device, the second message including an indication of a difference between a receipt time of the acknowledgement message at the other network device adjusted for an RF delay of the other network device determined at the other network device by a transmission-to-self calibration and a transmission time of the first message from the other network device; and
calculating, at the client device, the location of the client device based on a receipt time of the first message at the client device, a transmission time of the acknowledgment message from the client device, the indication of the difference included in the second message, and the known location of the other network device.
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Accused Products
Abstract
Methods for determining a location of a client device in a wireless network having at least a first other network device with a known location are disclosed. Transmission-to-self calibrations are performed at the first other network device and/or the client device to determine RF group delay of the first other network device and/or the client device. The client device receives messages and acknowledgements from the other network devices and determines its location based on information received including the time at which it received the messages, the acknowledgements and the RF groupdelay of the first other network device. As such, the location calculation can be refined by accounting for the RF group delays of the first other network device and/or the client device.
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Citations
8 Claims
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1. A method for determining the location of a client device in a wireless network including the client device and at least one other network device having a known location, the method comprising:
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determining a RF delay of the client device by performing, at the client device, a transmission-to-self calibration; receiving, at the client device, a first message transmitted by the other network device to the client device; transmitting, from the client device, an acknowledgement message to the other network device in response to receiving the first message; receiving, at the client device, a second message transmitted by the other network device to the client device, the second message including an indication of a difference between a receipt time of the acknowledgement message at the other network device adjusted for an RF delay of the other network device determined at the other network device by a transmission-to-self calibration and a transmission time of the first message from the other network device; and calculating, at the client device, the location of the client device based on a receipt time of the first message at the client device, a transmission time of the acknowledgment message from the client device, the indication of the difference included in the second message, and the known location of the other network device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for determining a location of a client device in a wireless network including the client device and at least a first other network device and a second other network device both having known locations, the method comprising:
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receiving, at the client device, a first message transmitted by the first other network device to second other network device; receiving, at the client device, an acknowledgement message transmitted by the second other network device to the first other network device in response to the second other network device receiving the first message; receiving, at the client device, a second message transmitted by the first other network device, the second message including an indication of a difference between a receipt time of the acknowledgement message at the first other network device adjusted for an RF delay of the first other network device determined at the first other network device by a transmission-to-self calibration and a transmission time of the first message from the first other network device; and calculating the location of the client device based on based on a receipt time of the first message at the client device, a receipt time of the acknowledgment message at the client device, the indication of the difference included in the second message, and the known locations of the first other network device and the second other network device.
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Specification