Research On Hybrid MAC Protocol Of Underwater Acoustic Heterogeneous Sensor Network

Underwater Sensor networks(UWSNs)have been widely used in monitoring the Marine environment,detecting seabed targets and collecting Marine data,which has attracted close attention from both military and civilian fields.UWSNs is characterized by the use of acoustic communication.As the underwater acoustic channel is characterized by low bandwidth,long propagation delay and high bit error rate,it is very important to build an efficient communication network.To realize efficient data transmission,one of the keys is to design MAC protocol according to the characteristics of underwater acoustic channel.In this paper,according to the characteristics of the large acoustic heterogeneous sensor network and the characteristics of the underwater acoustic channel is unique,in this paper,a clustering network model,and aimed at small-scale intensive sensor network within a cluster of the dynamic variation of the load problem,cluster head nodes in data transmission when the funnel effect and exposed terminal problems in the agreement,the proposed hybrid MAC protocol for communications within the cluster and the cluster communication between MAC protocol.For intra-cluster communication,LSHP(Load Self-adaptive Hybrid Protocol)is designed for dynamically changing network Load.LSHP fuses TDMA and CSMA/CA protocols together and selects the optimal protocol for data transmission according to the network load,which solves the problem that a single protocol cannot make efficient use of underwater acoustic channel.By designing the optimal retreat algorithm,the optimal retreat times of the competing nodes are obtained,and the network delay is reduced.For inter-cluster communication,a Slotted FAMA based on multi-data packet Sequential acceptance mechanism is proposed to solve the funnel effect problem on the club-head node when transmitting data to a base-station.Mc-sfama is a MAC protocol based on slotted-Fama multi-reception mechanism.For the slotted-Fama protocol,the problem of exposed terminals was solved by regulating ACK to control the time of packet sending.Multiple receiving mechanism is designed to allow a receiving node to receive DATA from multiple sending nodes after completing a RTS/CTS handshake cycle,which alleviates the adverse effects brought by funnel effect.The simulation results show that LSHP protocol increases the design of slot protection time,reduces the network delay,improves the channel utilization,and can adapt to the dynamic changes of network load better.The Mc-sfama protocol increases the design of DATA sending timing compared with the same type of multi-receive mechanism protocol,thus reducing the energy overhead and improving the network throughput.