A Novel Method for Estimating the Relative Clock Offset between Skew-Free Clocks

Estimating the relative clock offset under asymmetric one-way delays is a hard problem. This paper reports the theoretical fundation for estimating the relative clock offset between a pair of master and slave clocks. The two clocks are equipped on a pair of nodes that are connected by a bi-directional connectivity with asymmetric one-way delays. The estimation requires the two nodes to perform a handshake by transmitting one packet along each of the two uni-directional paths. The sending and receiving times of a packet are measured according to the local clocks. The measured value of a one-way delay of a packet is calculated based on the locally recorded time stamps. The relative clock offset can be estimated based on the measured values of one-way delays.