Patent ID: 8363681

Claim:
A method for synchronizing a plurality of nodes on a communication network, comprising: exchanging a local clock time between a first node and a second node over the communication network, wherein the exchange comprises: transmitting a first packet from the first node to the second node, wherein the first packet includes a first packet clock time set to the local clock time of the first node at transmission time, and includes a scheduled arrival clock time, and setting the local clock time of the second node to the first packet clock time; performing a ranging method between the first and second nodes based on the local clock time exchanged, wherein the ranging method results in an estimated propagation delay between the first and second node, and wherein the ranging method comprises: transmitting a second packet from the second node to the first node, wherein the second packet is transmitted from the second node at the scheduled arrival clock time, and wherein the second packet is received by the first node at an actual arrival clock time, calculating and storing the estimated propagation delay at the first node, wherein calculating the estimated propagation delay is based on the scheduled arrival clock time and the actual arrival time, and transmitting a third packet from the first node to the second node, wherein the third packet comprises the estimated propagation delay; and adjusting the local clock time of either the first or second node based on the estimated propagation delay, thereby resulting in a synchronized local clock time between the first and second node.