A compatible and scalable clock synchronization protocol in IEEE 802.11 ad hoc networks

This paper studies the scalability and compatibility problems of clock synchronization in IEEE 802.11 ad hoc networks. The scalability problem of 802.11 timing synchronization has been recognized and studied by researchers in the field, but the proposed solutions are not meeting industry expectation. The compatibility issue is not well investigated by the research community yet. The compatibility issue is very important and practical because of the large deployment base of 802.11 networks. In this paper, we try to address both issues. We propose a simple, compatible protocol without any change of beacon format. The frequency adjustment is proved to be bounded and the maximum clock offset is controlled under 20 μs. It is a significant improvement over the current results in the field. The current solutions with similar complexity can only control the maximum clock offset around 125 μs for compatible solutions and 50 μs for non-compatible protocols.