Time-of-Flight Aware Time Synchronization for Wireless Embedded Systems
Roman Lim, Balz Maag, Lothar Thiele · International Conference on Embedded Wireless Systems and Networks · 2016
Accurate time synchronization is an important prerequisite for many applications. Synchronization down to sub-microsecond precision, as required by distributed control in automation or network eventanalysis, is prevalently a domain of wired or expensive GPS-enabled systems. Existing time synchronization protocols for wireless embedded systems exhibit errors that are orders of magnitude higher. We identify propagation delay compensation as a key requirement to achieve sub-microsecond precision in typical deployments. As a result, we present the Time-of-Flight Aware Time Synchronization Protocol (TATS), a new protocol that combines fast multi-hop flooding and message delay compensation at similar message cost as existing delay-unaware protocols. Experiments conducted in a public testbed of 31 nodes show that TATS achieves sub-microsecond synchronization error over 22 hops, while outperforming state-of-the-artprotocols by a factor of up to 6.9.