| Time synchronization is an important research subject of wireless sensor networks(WSNs).Many applications of WSNs,such as environmental monitoring,target tracking,etc.,require all sensor nodes to have a common time reference,therefore it is significant to study on clock synchronization problem.Considering the case that the networks cannot achieve absolute synchronization with random bounded communication delay,this paper studies synchronization error based on the state-of-the-art consistency time synchronization algorithm based on least squares estimate(LSTS algorithm).It focus on factors that affect synchronization error between nodes,the influence of small world inWSNs and the experiments of ATS,MTS and LSTS algorithms.Details are as follows:1?It is found in MATLAB simulation that under LSTS algorithm,there are obvious differences between different nodes in synchronization error.This paper points out that on the basis of regular network,the distance and the difference of degrees between compared nodes have important effects on the synchronization error.The symmetry in synchronization error in the regular networks is also found.2?The theory of small world is introduced to the WSNs.The cases that random bounded communication delay between nodes and the topology of the WSNs is NW small-world networks based on single ring structure are considered.The relationship among convergence time,synchronization accuracy that statistically achieved based on LSTS time synchronization algorithm and the connection probability p under small world structure is studied through statistic MATLAB simulations.3?The test performance of three fully distributed algorithms,ATS,MTS and LSTS,with millisecond communication delay is studied on the object platform,and the result shows that LSTS has better synchronization performance.The robustness of LSTS is verified,and the influence of unsafe information and how to ensure the safety of information are described. |
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