Design Of Geographical Routing Protocol For Underwater Acoustic Sensor Networks

With the continuous growth of human demand for energy,the increasingly depleted terrestrial resources have been unable to meet the needs of global economic development.The whole world has turned its attention to the rich marine resources.Underwater routing protocols play an important role in realizing the informatization of marine resource development and utilization.However,the communication between underwater sensor nodes is prone to the hidden terminal problem.Hidden terminals cause nodes to forward redundant data packets when routing,which eventually lead to premature exhaustion of node energy and death.In addition,the opportunistic forwarding strategy commonly used in underwater routing has the problems of high delay and low delivery rate.Therefore,how to effectively avoid the hidden terminal problem and reasonably improve the performance of the opportunistic forwarding mechanism is the main problem of this paper.Firstly,this paper introduces two-dimensional underwater acoustic sensor network,three-dimensional static underwater acoustic sensor network and three-dimensional dynamic underwater acoustic sensor network with underwater robot and analyzes their characteristics.Three-dimensional static sensor network is used as the structural model of this paper.This paper analyzes the characteristics of underwater geographical routing protocol,such as energy,delay,delivery rate,mobility,and easy formation of communication void,and provides theoretical basis and optimization goals for the design of underwater geographical routing protocol.The model of sound velocity,noise and expected transmission count of underwater acoustic channel is analyzed,and a mathematical model is provided for the setting of simulation environment.The performance evaluation indicators such as data packet delivery rate,end-to-end delay and energy tax of underwater geographic routing protocol are introduced,and the performance of underwater routing protocol is analyzed based on this.Secondly,in view of the three-dimensional distribution of underwater nodes in the underwater acoustic sensor network and the low transmission rate,the communication between nodes is prone to the problem of hidden terminals.A forwarding chain model is constructed,and a geographic routing protocol based on forwarding chain is proposed,which improves the energy and delay problems of routing protocols in dense underwater acoustic sensor networks.In the neighbor information acquisition phase,a two-hop neighbor node information acquisition algorithm is proposed,so that each node has two-hop neighbor information.In the forwarding phase,a forwarding chain is constructed based on the information of the two-hop nodes,and the forwarding sequence is forwarded strictly according to the forwarding chain,so as to avoid the hidden terminal problem.Moreover,the exact waiting time of each node is calculated according to the forwarding chain,and the highest priority node does not need waiting time,which reduces the end-to-end delay caused by the waiting time.Thirdly,in view of the problems of high delay and low delivery rate when the geographic routing protocol of underwater acoustic sensor network uses the opportunistic forwarding mechanism,an adaptive multi-zone geographic routing protocol with multiple forwarding strategies is proposed.In the neighbor information acquisition phase,in view of the energy imbalance between nodes and the short node survival time,the proposed neighbor information acquisition algorithm can dynamically adjust the neighbor information acquisition cycle according to the speed of topology change,balance the energy between nodes,and prolong the node’s survival time.In the forwarding phase,in view of the problems of high delay and low delivery rate when the opportunistic forwarding mechanism is applied underwater,the routing protocol adopts an adaptive multi-zone cooperative forwarding mechanism,so that the proposed protocol not only inherits the characteristics of low energy consumption of opportunistic routing,but also has the characteristics of low end-to-end delay and high data packet delivery rate of the flooding mechanism,and realizes the simultaneous optimization of the performance of the routing protocol in terms of energy,delay and delivery rate.