| Underwater communication technology is conducive to the promotion of marine scientific research and plays an important role in the field of national defense.The use of underwater communication technology to establish a deep-sea communication network has important research significance.Deep sea communication network is a distributed,multi-node,large area coverage underwater communication system consisting of underwater base stations,surface gateways and two-way acoustic links between them,which are placed on the seabed or in the sea.It can collect,process and forward the information of marine targets and realize the sensing of various types of vehicles in deep sea environment.Due to the complexity of hydroacoustic channels,it brings many uncertainties to underwater multi-node cooperative detection and communication.The architecture design,data transmission and effectiveness issues of hydroacoustic networks are to be studied in depth.This paper revolves around the communication base station,combining underwater communication and sonar positioning technology to establish a deep-sea communication network and conduct experimental verification.The main research of this paper includes the following three items.1.Based on the physical characteristics of the South China Sea and the characteristics of hydroacoustic propagation,the deep-sea hydroacoustic communication network architecture with physical layer,link layer and network layer is proposed.In the physical layer,in order to solve the modulation problem,a sparse channel estimation method based on sparse Bayesian learning for hydroacoustic orthogonal frequency division multiplexing is proposed,and the performance indexes such as channel mean square error,frequency response mean square error and receiver false bit rate are simulated and analyzed to improve the accuracy of hydroacoustic channel estimation.At the link layer,to solve the data transmission problem,a minimum frame cycle link scheduling method based on the conflict model is proposed,a solution that maximizes network throughput and energy consumption while avoiding conflicts and interference between channels.2.In order to improve the positioning accuracy and detection effectiveness of deep-sea hydroacoustic networks,algorithms are studied for the multi-static sonar positioning problem and the optimal selection problem of multi-static network.Firstly,the resource allocation method of deep-sea dual/multi-base sonar positioning is proposed,and the optimal separation angle of the system is deduced by calculating the lower bound of Crameruo for bistatic sonar positioning accuracy,and the optimal deployment of sonar stations is carried out accordingly to improve the positioning accuracy of the system.Secondly,convex optimization theory is introduced into the multi-static optimal selection problem,and a multi-static selection algorithm based on the projected gradient method is proposed,which achieves higher convergence speed with less memory occupation.3.The design of deep-sea communication network base station and field test verification are carried out.Firstly,a deep sea communication network base station shell,and a kind of fiber grating sensor are designed and processed.Through this sensor,the pressure on the base station shell can be monitored in real time to ensure the health of the deep-sea base station,and then ensure the normal operation of the whole deep-sea communication network.Secondly,the multi-node hydroacoustic communication network field test was carried out to verify the effectiveness of the simulation algorithm by testing the transmission distance,communication rate and two-hop communication function of three underwater nodes,and then provide reference for the construction of large-scale deep-sea communication network. |
