Consensus-based Clock Synchronization for Wide Area Networks

Abstract

To have a global time clock is important for many latency-sensitive wireless network applications, including the industrial Internet-of-Things, the distributed time division multi-access (TDMA) scheduling and network localization. As the unknown propagation delays between the distributed nodes presents a challenge to network time synchronization, this paper proposes to eliminate the impact of the propagation delays upon network clock synchronization via having all the nodes broadcast beacons to their one-hop neighbors. For a performance benchmark, we first consider a simplistic scenario where the time-stamp information broadcasted from all the nodes can be gathered by a central node, and propose a centralized algorithm to estimate (and henceforth to compensate) not only the time offsets but the skewness of the nodes’ clocks against a virtual global consensus. Despite its optimum performance, the benchmark algorithm requires some major overhead to aggregate all the information at a central node. To reduce the overhead, we propose a distributed algorithm, in which the nodes use only the time-stamp information of its own and of its one-hop neighbors to reach consensus through rounds of beacon broadcasting. Simulation results verify the effectiveness of both algorithms. We find that the sprawling area of the network does not affect the synchronization performance.