The Simulation Research Of The Network Protocols For The Underwater Acoustic Communication Mobile Nodes

As countries are looking to the larger ocean space,unmanned underwater vehicle as an important means of combat and access to information has become the focus of marine development research and the core of the combat in the future.At the same time,the unmanned underwater vehicle's coordination is related to the operational efficiency of the underwater mobile network.In order to further enhance the flexibility and high efficiency of its mobile underwater network,it is urgent to study on the coordination and formation for underwater mobile networking technology.Meantime,underwater mobile network simulation technology is widely optimistic because of its low cost,low hardware platform and flexible operation.This paper is based on such requirements to carry out related research work.Firstly,we design an underwater mobile node model in OPNET platform,including simulation mechanism and process research,keeping in view the features of the underwater mobile environment pipeline modeling and node movement modeling.Furthermore we select the spread spectrum communication as a modulation method and the physical simulation nodes in different SNR-BER curve under the speed to move,in order to close to the underwater environment.According to the application requirements,the two kinds of mobile network of data acquisition and long-distance communication are classified,and their corresponding topological structure and research content are determined,which lays the foundation for the subsequent simulation.Secondly,given the network protocol performance evaluation standard of the mobile network and completed the analysis of the applicable MAC layer protocol for the data collection class mobile network.The paper designed the network tri-message time synchronization protocol,and TDMA protocol based on the time slot redistribution.Simulation network clock offset correction in OPNET simulation platform,to explore the effectiveness of time synchronization protocol and the limits of its mobile case.By obtaining the skew and offset parameters,it is found that in this topology environment,the moving speed of the mobile node is in good time synchronization performance under 8 knots,satisfying the aggregation business requirements.Then simulate the improved TDMA protocol and tradional TDMA protocal,including network throughput,packet loss rate,end-to-end delay.The results verify that the performance of the improved TDMA protocol network is better than the traditional TDMA protocol.Further,the paper analysed the MAC and routing layer protocol which appropriate to the long-distance communication class mobile network,completed the principle analysis and process layer design of MACAU and AODV protocols on the simulation platform.On the routing layer,the performance and effectiveness of the road are proved by the aspects of end-to-end delay,average hops,throughput,mobile efficiency and topological adaptability.Finally,on the MAC layer of the long-distance communication class mobile network,the paper simulated the protocols of ALOHA and MACAU,conducted the performance of the two protocal through the simulation results of end-to-end delay,packet loss rate and throughput.It is found that the ALOHA protocol has a slight advantage in the throughput of the instruction(short frame)transmission,but in the overall comparison,the performance of the MACAU based on the handshake and channel silent mechanism is better than the ALOHA protocol.The underwater long-distance communication class mobile network adopts the MACAU protocol on the MAC layer and use AODV design on the routing layer can meet the demand of long-distance communication class mobile network.