Joint ranging and clock synchronization for a wireless network

Synchronization and localization are two key aspects for the coherent functioning of a wireless network. Recently, various estimators have been proposed for pairwise synchronization between two nodes based on time stamp exchanges via two way communication. In this paper, we propose a closed form centralized Global Least Squares (GLS) estimator, which exploits the two way communication information between all the nodes in a wireless network. The fusion center based GLS uses a single clock reference and estimates all the unknown clock offsets, skews and pairwise distances in the network. The GLS estimate for clock offsets and skews is shown to outperform prevalent estimators. Furthermore, a new Cramer Rao Lower Bound (CRLB) is derived for the entire network and the proposed GLS solution is shown to approach the theoretical limits.