Clock offset estimation with bias correction
AssigneeLucent Technologies Inc.
InventorsMooi Choo Chuah, Daniel R. Jeske, Muralidhran S. Kodialam, Ashwin Sampath, Anlu Yan, On-Ching Yue
Life of this patent
Estimating the term…
Abstract
A new algorithm for clock offset estimation for resources distributed across a network (such as the Internet). By exchanging a sequence of time-stamped messages between pairs of network nodes and separately estimating variable delays for each message direction, present inventive embodiments provide estimates for clock offset between node pairs and the bias of such estimates, thereby to permit more accurate correction. Present inventive algorithms operate in a variety of peer and server network configurations while providing significant improvement in convergence speed and accuracy.
Claims17
In a network having a plurality of network nodes, each node having a clock, a method for determining information at a first network node for adjusting a clock at a selected second network node, the method comprising
- determining an estimate of the offset of said clock at said second node relative to the clock at said first node, and
- determining an estimate of bias of said estimate of said clock offset,
- said determining an estimate of the offset and said determining an estimate of bias comprising exchanging a plurality of rounds of ordered time-stamped messages between said first node and said second node.
In a network having a plurality of network nodes, each node having a clock, a method for adjusting a clock at a selected second node to be more nearly in synchronism with a clock at a first node, the method comprising
- determining an estimate of the offset of said clock at said second node relative to the clock at said first node,
- determining an estimate of bias of said estimate of said clock offset, and
- sending said estimate of said offset and said estimate of said bias to said second node to effect said adjustment of said clock at said second node,
- said determining an estimate of the offset and said determining an estimate of bias comprising exchanging a plurality of rounds of ordered time-stamped messages between said first node and said second node.
Dependencies are inferred from the claim text.