A hybrid time synchronization algorithm based on broadcast sequencing for wireless sensor networks

Abstract

In recent years, time synchronization has emerged as an essential research topic for wireless sensor networks. Numerous wireless network applications require a common reference time for collaborative data fusion and communications. Other time synchronization protocols have been proposed over the years, but none have eliminated the possibility of collisions associated with wireless packet transmissions while maintaining a precise level of synchronization for any given topology. In this thesis, we present a new hybrid time synchronization scheme that provides a high degree of network-wide synchronization and eliminates the possibility of collisions when transmitting timestamp messages. We propose an algorithm that allows a network to determine a broadcast sequence by which nodes transmit and forward messages and then conducts a network-wide synchronization based on received timestamp information. The proposed hybrid time synchronization scheme utilizes two existing protocols, namely relative referenceless receiver/receiver synchronization and ratio-based synchronization protocol, that provide a high degree of precision. We implement our broadcast sequencing algorithm in simulations and demonstrate its effective performance for a series of network topologies. We also present results demonstrating an improvement in network-wide synchronization using our hybrid scheme over other time synchronization protocols.