Design And Research Of MAC Protocol For Underwater Hybrid Optical-acoustic Wireless Sensor Network Based On Competition

Competition among ocean powers,competition for strategic resources and blue enclosures are the international background for the development of marine science and technology today.Underwater sensor networks play an important role in marine data collection,pollution monitoring,offshore exploration,disaster prevention,assisted navigation and tactical surveillance.However,the current underwater acoustic communication wireless sensor network cannot solve the problem of high-speed wireless transmission of real-time video and image in ocean sound detection due to the limitation of sound transmission rate.Combined with the characteristics of high-speed transmission of underwater optical communication,the research group proposed underwater hybrid optical-acoustic wireless sensor network.This paper studies the media access control protocol of hybrid optical-acoustic wireless sensor network,including the following aspects:Firstly,aiming at the current status of MAC protocol for underwater wireless sensor networks,a novel contention-based hybrid optical-acoustic wireless sensor network MAC protocol(OA-CMAC)is proposed.The protocol integrates acoustic and optical communication,uses low-rate acoustic communication to transmit small data such as temperature and salinity,and uses high-rate optical communication to transmit large data such as images and videos,thereby improving data transmission rate and breaking the problem of difficult transmission of large data information such as underwater images and videos.At the same time,the protocol considers the node energy consumption problem,and increases the node life cycle by adding an energy threshold module.Secondly,aiming at the proposed competition-based hybrid optical-acousticwireless sensor network OA-CMAC protocol,there will be cases where nodes have been unable to compete for channels in the process of node competition.An OA-HMAC protocol based on CSMA&TDMA hybrid optical-acoustic fusion wireless sensor network is proposed.The protocol divides the underwater fixed nodes into two types,one is an important node for monitoring important data or not dominant in the competition process,and the other is a common node.The protocol is also based on hybrid optical-acoustic communication for data transmission,however,in the data transmission phase,according to the type of successful node of the optical handshake,the frame structure is divided into three cases,and the node data transmission request is satisfied as much as possible to ensure that the data can be transmitted.In the simulation process,the fairness indicators of the two protocols are evaluated,and it is fully found that the OA-HMAC is more fair than the OA-CMAC protocol.Finally,the performance evaluation of the proposed underwater layer optical fusion wireless sensor network MAC layer protocol is realized by OMNeT++simulation software.The simulation results show that in the throughput simulation,when the optical handshake success rate is greater than 50%,the throughput of the OA-CMAC protocol is doubled compared with the O-A handshake protocol based on time slot allocation.In the energy consumption simulation,the lifetime of the OA-UWSN node is increased by 14% compared to the OA-UWSN node without the energy threshold,which is 30% longer than the lifetime of the optical and acoustic shaking hands at the same time OAs-CMAC.In the comparison of node fairness,the OA-HMAC protocol is improved by 0.12 compared with the OA-CMAC protocol fairness index.Using OA-CMAC protocol can achieve higher throughput and lower node energy consumption,suitable for underwater wireless communication environment with high load and large data.