Frequency offset compensation for wifi ranging

A method for clock compensation between i) a first communication device utilizing a first clock having a first clock frequency, and ii) a second communication device utilizing a second clock having a second clock frequency, the method comprising:

• determining, at the first communication device, a first timestamp corresponding to when a first transmission is transmitted by the first communication device;
• determining, at the first communication device, a second timestamp corresponding to when a second transmission is received at the first communication device;
• compensating, at the first communication device, for a difference between the first clock frequency and the second clock frequency to provide a compensated first timestamp and a compensated second timestamp;
• sending, from the first communication device, the compensated first timestamp and the compensated second timestamp to the second communication device;
• and
• sending, from the first communication device, a compensation indicator to the second communication device, the compensation indicator indicating that the second communication device does not need to compensate for the difference between the first clock frequency and the second clock frequency with respect to the compensated first timestamp and the compensated second timestamp.

A first communication device configured to utilize a first clock having a first clock frequency, the first communication device comprising:

• a network interface configured to:
• determine a first timestamp corresponding to when a first transmission is transmitted by a second communication device that utilizes a second clock having a second clock frequency, and
• determine a second timestamp corresponding to when a second transmission is received at the second communication device;
• and
• a clock calculation and compensation unit configured to:
• determine whether a compensation indicator was received from the second communication device, and
• compensate for differences between the first clock frequency and the second clock frequency to provide a compensated first timestamp and a compensated second timestamp when the compensation indicator is not received from the second communication device,
• wherein a presence of the compensation indicator indicates that the first timestamp and the second timestamp are received in terms of the first clock frequency and do not need to be compensated.

A first communication device configured to utilize a first clock having a first clock frequency, the first communication device comprising:

• a network interface configured to:
• determine a first timestamp corresponding to when a first transmission is transmitted by the first communication device, and
• determine a second timestamp corresponding to when a second transmission is received at the first communication device, the second transmission having been transmitted by a second communication device configured to utilize a second clock having a second clock frequency;
• and
• a clock calculation and compensation unit configured to compensate for differences between the first clock frequency and the second clock frequency to provide a compensated first timestamp and a compensated second timestamp,
• wherein the network interface is further configured to cause the first communication device to send the compensated first timestamp and the compensated second timestamp and a compensation indicator to the second communication device, the compensation indicator indicating that the compensated first timestamp and the compensated second timestamp do not need to be compensated by the second communication device.