A Mutual Network Synchronization Method for Wireless Ad Hoc and Sensor Networks

摘要

Existing mutual network synchronization methods, however, make use of physical (PHY) layers and medium access control (MAC) sub-layers that are either proprietary or not widely available. CS-MNS is able to achieve microsecond network-wide synchronization accuracy for single-hop or multiple-hop topologies, and mobile or static wireless ad hoc and sensor networks. Different to existing mutual network synchronization approaches, the timing information is exchanged explicitly using periodic timestamp packets. These packets can be, for instance, the same beacons used in the IEEE 802.11 or IEEE 802.15.4 standards, which makes CS-MNS the first mutual network synchronization method that is compatible to these popular standards. A CS-MNS node adjusts the frequency of its clock recursively in the time domain by multiplying the time of its clock by a factor that is updated with any newly received timestamp. Sufficient stability conditions are derived for CS-MNS under certain scenarios via the discrete Lyapunov direct method. Additionally, several of the possible beacon transmission approaches are analyzed. Finally, thorough numerical results are presented that demonstrate at least one and two orders of magnitude improvement in scalability and accuracy are presented. Comparisons with TSF, MATSF and ASP are presented.