Patent ID: 7042868

Claim:
A method of determining a propagation time in a signal path of a wireless network, comprising: sending a first ranging packet from the local device to the remote device at a first time; receiving the first ranging packet at the remote device at a second time, where the second time is equal to the first time plus the propagation time; sending a second ranging packet from the remote device to the local device at a third time, where the third time is equal to the second time plus a first hold time; receiving the second ranging packet at the local device at a fourth time, where the fourth time is equal to the third time plus the propagation time; sending a third ranging packet from the local device to the remote device at a fifth time; receiving the third ranging packet at the remote device at a sixth time, where the sixth time is equal to the fifth time plus the propagation time; sending a fourth ranging packet from the remote device to the local device at a seventh time, where the seventh time is equal to the sixth time plus a second hold time, the second hold time being different from the first hold time; receiving the fourth ranging packet at the local device at a eighth time, where the eighth time is equal to the seventh time plus the propagation time; and calculating the propagation time at the local device as a function of the first time, the fourth time, the fifth time, the eighth time, and a proportion between the first hold time and the second hold time.