Patent ID: 7415044

Claim:
A communications system comprising: a first node having a first oscillator for sending multiple messages over a network and including or associating with each message a first timestamp corresponding to a time when the first node sent that message, and a second node having a second oscillator for receiving each message and including or associating with that message a second timestamp corresponding to a time when the second node received that message, wherein one of the first and second nodes is configured to determine for each message a first time difference between the corresponding first and second timestamps, and from multiple first time differences, to fit a line to two or more minimum delay values of the first time differences, a characteristic of the line being related to a frequency drift between the first and second oscillators, wherein the one node is configured to determine from the line a frequency adjustment to synchronize the first and second oscillators, and wherein the characteristic of the line is a slope ρ of the line and the one node is configured to adjust the second oscillator by a factor of 1−ρ.