Time Synchronization Algorithms In ZigBee Wireless Sensor Networks

It is well known that the issue of time synchronization in wireless sensor network is a key factor in practical applications. Moreover, with energy constraint in ZigBee sensor networks, a highly efficient time synchronization scheme is especially important. In this thesis, we first introduce the structure, characteristics and composition of wireless sensor networks. Then we introduce some existing time synchronization algorithms for wireless sensor networks, including FTSP, RBS, TPSN, LTS and DMTS algorithms, and campare their performance in terms of implementation steps, synchronization theories, complexity, and synchronization accuracy. Based on the analysis, we found that FTSP is more appropriate for Zig Bee networks because it is simple and accurate, and it has a structure similar to ZigBee. But FTSP has a weakness of complex topology thus big energy comsumption when applied in ZigBee networks. Motivated by the idea of neighbor nodes and micro area, we propose an enhanced FTSP algorithm(named EFTSP) that integrate the subset algorithm in FTSP in an attempt to simplify the network topology thus reduce the power comsumption by removing redundant transmission links in the network. Simulation results based on Matlab show that the EFTSP algorithm is simple and can reduce topology complexity significantly thus reduce power consumption significantly. On the other hand, the shortage of this algorithm is that it cannot apply to the chain topology. But we can solve this problem by adding some conditions in the subset algorithm.