Research On Wireless Ad Hoc Network Time Synchronization Technology

Mobile Ad Hoc network is a kind of distributed network which has no control center.It is unnecessary for it to rely on the existing fixed communication network infrastructure.Nodes in the network can dynamically,optionally enter or leave the network with a little human intervention in case of having no influence on the communication of other nodes.Therefore,the mobile ad hoc network has great performances of fast-networking and anti-destruction,and fits for working in the environment for which the traditional mobile communication network is not qualified.At present,the research and application on the mobile ad hoc network has developed into an independent branch in communication fields,and is regarded as an important part of personal communication system in the future.As a supporting technology in mobile ad hoc network,time synchronization has great value in research and application naturally.In this paper,we make great efforts to analyze and study the traditional time synchronization algorithm in mobile ad hoc networks.By making contrasts in aspects of algorithm complexity,convergence speed and synchronous precision,we focus on the study of the distributed time slot synchronization algorithm and the firefly synchronization algorithm.Between them,the distributed time slot synchronization algorithm can achieve a very high synchronization accuracy.However,its propagation mechanism is complex and it converges slowly.The firefly synchronization algorithm,which originates from the phenomenon of synchronous luminescence of the firefly in nature,has simple synchronous mechanism,small signaling overheads and fast convergence speed.However,it has time-delay sensitivity.Besides,the synchronization accuracy is limited by the propagation delay in the network.As a result,it is not suitable for wireless networks with large delay.In regard to these problems,based on the advantages of the two algorithms proposed above,we present a combined synchronization algorithm and an adaptive delay compensation firefly algorithm to achieve the purpose of the fast time synchronization with high precision in large-scale wireless ad hoc networks.The simulation results indicate that the convergence speed of the combined synchronization algorithm is significantly faster than the time slot synchronization algorithm,the goal of fast mutual synchronization of the system is realized.Meanwhile,by giving compensation for the propagation delay of signal in the receiving end,the two strategies overcome the shortcoming of the synchronization accuracy of traditional firefly algorithms is limited by the propagation delay between nodes,reach a stable convergence of the subtle level synchronization error among the nodes in the whole network when applied to large-scale mobile ad hoc networks.In follow-up studies,we will improve the two proposed methods to reduce the complexity and meet the requirements of practical application.