Research On Underwater Real-time Wireless Communication Technology Based On Blue-green Laser

Life comes from the ocean,and the exploration of the ocean is an eternal proposition of mankind.Valuable resources in the ocean not only play an important role in international business and fisheries,but also play a pivotal role in environmental monitoring,climate change and the international relation.Among them,underwater communication is an important technology for human exploration of the ocean.Wireless communication mainly includes three types:water acoustic communication,electromagnetic communication and underwater optical communication.Compared with these three methods,underwater optical communication has the advantages of higher transmission bandwidth,lower link delay,higher data rate etc.It is an ideal underwater communication technology.In this paper,because of the low attenuation of blue-green light underwater,the research is carried out around the underwater blue-green laser real-time communication system.The work is as follows:(1)The paper introduces the basic model of underwater real-time wireless optical communication system,the underwater real-time signal processing system is designed and implemented on the FPGA development board by Verilog hardware programming language.The correctness of the function of each module was verified by simulation and development board.(2)The real-time underwater optical communication experimental system is built in the laboratory,and the transmission performance of the system are tested and verified.From the experimental results,the underwater blue-green laser real-time communication system proposed in this paper can achieve error-free transmission with a transmission distance of 4 meters and a transmission rate of 75 Mbps.(3)We demonstrate QAM-based stream cipher(QSC)for underwater wireless optical communication.Experimental results show the system using QSC has only 1dB penalty and guarantees the security of the system compared to QPSK without encryption.