Research On MAC Protocol Of Underwater Acoustic Communication Network Based On Handshake Mechanism Under Large Propagation Delay

Underwater Acoustic Communication Networks have tremendous application prospects in the fields of marine resource explorations,military monitoring,marine environmental protection,etc.,which have attracted widespread attention around the world.As one of the key technologies of the underwater acoustic communication network,Media Access Control(MAC)is responsible for allocating the underwater acoustic channel resources reasonably and ensuring the reliable transmission of data.However,due to the long propagation delay,narrow effective bandwidth,and high bit error rate of the underwater acoustic channel,the design of the underwater acoustic MAC protocol has encountered huge challenges.It is vital to study and design effective underwater acoustic MAC protocol according to the characteristics of the underwater acoustic channel.This thesis focuses on the multi-node competition and low channel utilization to improve the performance of handshake based MAC protocol.The main research contents include:1.Aiming at the problem of multi-node competition leading to failure of handshake,a slotted handshake based ordered scheduling MAC protocol(HOS-MAC protocol)is proposed.In the HOS-MAC protocol,the threshold of the number of packets is dynamically set to control channel reservation,reducing the number of competing nodes.And the multi-node reservation mechanism allows multiple pairs of nodes to successfully reserve channels in the same time slot,effectively solving the problem of handshake failure caused by multi-node competition..Data transmission allows the sending node and multiple receiving nodes to perform bidirectional concurrent data transmission.And reasonably calculating the sending time slot of each sending and receiving node pair.Compared with typical protocols,the HOSMAC protocol can effectively improve the effectiveness of handshake and the network throughput performance.It’s average energy consumption is lower.2.In response to the problem of low channel utilization of traditional handshake protocols caused by the propagation delay,the handshake based polling appending transmission MAC protocol is proposed.HPA-MAC protocol uses control packet snooping and contention comparison mechanism to select sending node to solve multi-node contention problem.After the receiving and sending nodes finish the data transmission,the neighbor nodes are allowed to access the sending node in a polling manner to improve the utilization of network channels and enhance the fairness of the network.Due to the delay relationship between nodes,neighbor nodes can transmit data to the sending node in parallel,reducing data waiting time.The simulation results show that compared with HOS-MAC protocols,HPA-MAC protocol effectively improve network throughput,effectively reduce end-to-end delay compared to HOS-MAC,and network fairness increases with load growth.But the average energy consumption is higher than HOS-MAC.