Research On Time Synchronization And Routing Mechanism For Heterogeneous Underwater Acoustic Sensors Networks

In recent years,as the research on underwater vehicles has become more and more mature,the underwater vehicles are often added to Underwater Acoustic Sensor Networks(UASNs)to form Heterogeneous UASNs that utilizes the mobility of the vehicles to perform large-scale marine dynamic monitoring tasks.However,the complex and variable underwater acoustic environment and the limited energy of nodes make the reliability and effectiveness of communication low.Therefore,this paper studies the time synchronization(TS)and routing protocols.Aiming at the waste of control frames caused by the separated TS and multiple access procedures during the communication among nodes,this paper designs a mechanism for integrated TS and multiple access procedures——TS-MAC.TS-MAC combines the control frame of TS and of the multiple access,effectively reducing the number of frame exchanges during data transmission,thereby reducing the network energy consumption and improving the energy efficiency.In addition,in order to ensure the communication among nodes is not interfered by marine mammals and improve the network lifetime,this paper proposes an energy-efficient and obstacle-avoiding routing algorithm——EOAR.EOAR is based on the network cross-layer model,adding node information and link information to the routing decision,ensuring effective communication among nodes in the case of marine mammalian interference.It considers the residual energy of the nodes,thereby balancing the energy consumption among nodes and extending the network lifetime.The simulation results show that TS-MAC improves the TS accuracy compared with the classic TS algorithm MU-Sync and E~2DTS,which can effectively reduce energy consumption and also improve energy efficiency compared with the algorithms of separated TS and multiple access.Compared with the classic routing protocols HHVBF and VHGOR,EOAR can make the communication link free from the interference of marine animals,improve the packet delivery rate,reduce the propagation delay and energy consumption,and prolong the network lifetime.