Research And Analysis On Time Synchronization Cumulative Error In Wireless Sensor Networks

Wireless sensor network is a self-organizing system that includes information acquisition,information processing,and information transmission.As one of the core technologies in wireless sensor networks,time synchronization technology plays an important role in the design and application of WSNs.At present,most wireless sensor networks are composed of one or more reference nodes and multiple ordinary nodes.The nodes communicate with each other through the topology.Therefore,it is of great significance to implement time synchronization protocols with lower network-wide synchronization errors and faster convergence.This paper studies the time synchronization algorithm of the master-slave structure.Firstly,the factors that affect the clock synchronization accuracy of wireless sensor networks are analyzed.Then this paper theoretically analyzes the clock synchronization principle using the LSM algorithm and the jitter of synchronization error.And this paper proposes a WLSR clock synchronization algorithm that can reduce clock synchronization errors.Finally,aiming at the accumulation of clock synchronization errors in multi-hop communication networks,a GCS-PCS clock synchronization protocol was proposed to improve the synchronization accuracy of the entire network.The performance of the proposed clock synchronization protocol is tested by simulation experiments.The specific research contents of this article are as follows:(1)The jitter analysis of the estimation algorithm based on the least square method(LSM)in the time synchronization protocol was performed.Aiming at the distribution characteristics of synchronization errors,a weighted least square method of recursion(WLSR)correction algorithm was proposed.The compensation parameter makes up for the synchronization error caused by the instability of the transmission link or the frequency jitter of the crystal oscillator.In the simulation experiment,the WLSR and LSM algorithms are compared and verified by introducing noise such as time transmission delay and frequency jitter of the crystal oscillator.The results show that the WLSR synchronization algorithm effectively improves the accuracy of time synchronization.(2)Based on the LSM and WLSR clock synchronization algorithms,the relationship between the cumulative clock synchronization error and the node hop distance in the entire network is mainly studied.A clock synchronization protocol based on the global clock synchronization--pseudo clock synchronization(GCS-PCS)is proposed.Through the pseudo-logic clock of the PCS,the error accumulation noise of the clock synchronization process is eliminated to complete the clock synchronization of the global network.In the simulation experiment,the proposed GCS-PCS clock synchronization protocol is analyzed and verified,and the GCS-PCS_WLSR,GCS-PCS_LSM,LSM,and WLSR protocols are compared.The results show that the GCS-PCS clock synchronization protocol effectively improves the accuracy of time synchronization and reduces the cumulative error of the clock.