Design And Performance Evaluation Of Environment-friendly MAC Protocol With High Reliability For Underwater Acoustic Sensor Networks

Most research about underwater acoustic sensor networks(UASNs)focuses on how to realize underwater communication in a single network while paying little attention to reliability of communication and multiple networks.However,natural acoustic systems consisted of marine mammals and artificial acoustic systems consisted of nodes in UASNs coexist in the ocean.Artificial communication systems like sonars have influenced normal lives of marine mammals.Thus,focus of researches should be moved from single networks to multiple networks including marine mammals.Besides,considering complex and changeable underwater environment,scholars should also pay attention to the reliability of underwater communication.The paper briefly introduces recent study on MAC protocols for UASNs and emphatically illustrates CDMA-based,ALOHA-based and CSMA-based MAC protocols.The paper also illustrates existing localization algorithms for static networks,mobile networks and hybrid networks respectively.To solve the spatial fairness problem in UASNs and the problem caused by long propagation delay of underwater channels,as well as to realize reliable underwater communication while guaranteeing the harmonious coexistence of marine mammals and UASNs,an environment-friendly high-reliability MAC protocol for underwater acoustic sensor networks is proposed in the paper.The protocol consists of environment sensing and cooperative communication.During environment sensing period,the current area where marine mammals are located is firstly predicted using the newest positions and speed of marine mammals.Then,based on the prediction results,nodes determine whether to start communication or not.The subsequent period applies cooperative communication to MAC layer by designing the scheme of competition and participation in cooperative communication.The design realizes flexible scheduling of cooperative communication,which enables the improvement of communication while reducing unnecessary consumption of energy.Besides,in assistance of environment sensing,the localization algorithm and speed measurement algorithm for marine mammals are proposed in the paper.In the end of the paper,performances of the localization algorithm,speed measurement algorithm and protocol of the cooperation period are evaluated through simulations.