Research And Implementation Of The MAC Protocol For Underwater Acoustic Networks Based On TDMA Protocol

In order to explore and develop marine resourcesand protect the security of national territorial sea,a large number of researches have been carried out on underwater acoustic communication network both at home and abroad in recent years.Media Access Control(MAC)protocol is one of the key technologies of underwater acoustic Ad-hoc networks.The first task is to allocate the underwater acoustic channel resources reasonably and guarantee the transmission reliably.The underwater environment is special and complex,especially long delay and narrow bandwidth,which challenges the design of MAC protocol.Therefore,there is an urgent task to design anunderwater acoustic communication MAC protocol which canincrease the network throughput and reliability and reduce the power consumption and transmission delay.This paper carries out the following work on the basis of existing MAC protocol of underwater acoustic sensor network.Firstly,we analyze the problems of the MAC protocol and study the principles of some existing MAC protocols such as ALOHA,traditional TDMA,DACAP,T-LOHI,etc.we also analyze and study the framework and principle of NS2 and its extended network simulation software,laying a foundation for the simulation of the MAC protocol of underwater acoustic sensor network.Secondly,on the basis of the TDMA,we design a MAC protocol based on the slot reservation(SR-TDMA).The MAC protocol adds reservation mechanism and dynamically adjusts the length of each cycle by monitoring the numbers of reservation information which is sended by sensor nodes in the network.The MAC protocol avoids the waste of idle time and improves the network performance.And then,we compare SR-TDMA with ALOHA and traditional TDMA to analyze performance of the network.Also,we optimize the data packet length and packet generation cycle by simulation and analyze its applicability.Finally,we design an adaptive MAC protocol based on ALOHA and SR-TDMA,which can select whether to switch the protocol to avoids the high packet loss rate of the ALOHA protocol and the long delay of the SR-TDMA protocol.The simulation proves that the adaptive MAC protocol has better performance of the network.