In this paper, we propose a fully distributed algorithm for joint clock skew and offset estimation in wireless sensor networks based on belief propagation. In the proposed algorithm, each node can estimate its clock skew and offset in a completely distributed and asynchronous way: some nodes may update their estimates more frequently than others using outdated message from neighboring nodes. In addition, the proposed algorithm is robust to random packet loss. Such algorithm does not require any centralized information processing or coordination, and is scalable with network size. The proposed algorithm represents a unified framework that encompasses both classes of synchronous and asynchronous algorithms for network-wide clock synchronization. It is shown analytically that the proposed asynchronous algorithm converges to the optimal estimates with estimation mean-square-error at each node approaching the centralized Cramér-Rao bound under any network topology. Simulation results further show that the convergence speed is faster than that corresponding to a synchronous algorithm. Index Terms-Clock synchronization, wireless sensor network, factor graph, asynchronous algorithm. Jian Du received the B.Eng. and M.Eng. degrees in communication and information engineering from
Based on belief propagation, a fully distributed timing protocol REF developing from the two-way sender-receiver synchronization scheme was used for the joint estimation of rate and offset.
Distributed Clock Skew and Offset Estimation in Wireless Sensor Networks: Asynchronous Algorithm and Convergence Analysis
IEEE Transactions on Wireless Communications
IEEE Transactions on Wireless Communications
Computer Science Mathematics