Research Of Reliable Transmission And Routing Protocols In Underwater Sensor Networks

Based on the frontier technical requirements of marine technology and coastal security problems faced by the national navy,we mainly investigate and solve the problem of reliable data transfer and routing protocols in underwater environment.The goal of this thesis is to construct underwater acoustic communication network with self-organization,high coverage,high efficiency and high reliability features,and meets the strategic needs of the development of national marine technology.The major contributions and work of this thesis include:1.We present the basic components of underwater sensor networks and the relevant models of underwater sensor network are analyzed and established.We also analyze and deduce the even-layer layered structure of underwater acoustic network,two kinds of general topology,underwater channel model,node energy consumption model and node mobile model.Based on these analysis,a simulation system of underwater acoustic sensor network is built.Therefore,the actual transmission of underwater sensor network can be well simulated.2.A reliable transmission protocol based on fountain code and hybrid automatic feedback retransmission is proposed for adaptive underwater acoustic sensor networks.The protocol makes full use of the broadcast characteristics of underwater nodes.The long distance unreliable transmission is replaced with the cooperative transmissions of multiple nodes,and the spatial diversity gain of the network is obtained by the independent encoding of each node and the joint decoding of the receiving node.The proposed protocol achieves a higher successful delivery rate with lower energy consumption.At the same time,the communication delay of the system is also relatively low,which realizes the tradeoff between delay and reliability.3.A novel underwater cross-layer routing protocol based on network coding and opportunistic reception is proposed.The protocol takes advantage of the multicast characteristics of underwater nodes and adds the auxiliary nodes to routing paths,which makes the underwater transmissions more robust to burst link damage.At the same time,the synchronous routing maintenance and data transmission mode are designed.Thus the proposed protocol can provide reliable communication link and reduce system delay for underwater communication.4.A routing protocol for power adaptive underwater sensor networks based on energy balancing and hot spot avoidance is proposed.The protocol takes into account the energy efficiency and energy balance.According to the different residual energy of nodes,the protocol adopts different transmission modes flexibly,which can obviously improve the battery efficiency of underwater nodes,and greatly prolong the network lifetime.Based on the research of underwater acoustic sensor network,we analyze the main factors that influences reliable transmission and routing protocols in underwater sensor networks.A simulation system of underwater acoustic sensor is constructed based on the network simulator.A reliable underwater data transmission protocol and two routing protocols with different optimization targets are proposed to improve the reliability and robustness of underwater data transmission and provide an effective design of underwater ad hoc networks.