Research On Energy Balanced Routing Algorithm For Underwater Sensor Networks Based On Rigid Graph Theory

Underwater wireless sensor network(UWSN)is considered as an important technology for exploring the ocean,and has attracted the attention of the scientific and industrial circles because of its potential for monitoring and exploring the water environment.Underwater sensor networks,however,is different from traditional ground sensor networks in that it uses acoustic waves to transmit data in communication mode.Underwater acoustic channel has the characteristics of high delay,low bandwidth and high bit error rate,which makes the network perform poorly in underwater environment.In addition,it is difficult to charge or replace sensor nodes in underwater environment,so energy saving is one of the most challenging problems in underwater wireless sensor network.Considering the characteristics of underwater acoustic environment,designing reasonable routing algorithm is of great significance and value to the research of underwater network.In order to improve the reliability of data transmission and balance network energy to prolong network lifetime,this paper proposes an Energy Balanced Routing Algorithm for Underwater Sensor Networks based on Rigid Graph Theory(EBR-RGT).Based on the theory of optimal rigid graph,a topology is constructed,which combines residual energy and link quality state in calculating link weights to eliminate bad links and ensure network connectivity.Based on the topology,an opportunistic routing algorithm for underwater wireless sensor networks is designed: 1)The link quality is evaluated according to the data transmission rate in the acoustic link,and the fitness factor of the candidate nodes is calculated by combining the layer information,residual energy and link quality of the sensor nodes,and the extended expected data packet advancement is proposed.The next hop forwarding candidate set is determined by solving the maximum clique problem to eliminate the hidden nodes in the candidate set.2)The priority of the node is determined according to the fitness factor of the candidate node.The node sets the timer according to the priority and waits for the forwarding of the packet.Only when the higher priority node fails to forward the packet successfully,the lower priority nodes will forward packets to reduce packet collision and redundant transmission,thus saving the energy of the whole network.Finally,EBR-RGT algorithm is implemented in Aqua-Sim simulation software,and compared with VBF and HHVBF.The simulation results show that the algorithm can significantly improve the data packet delivery rate,node energy consumption and network lifetime.