Underwater Acoustic DE-OFDM Communication Based On Speex

Underwater acoustic communication technology is widely used in various fields of Marine resources development,such as underwater vehicle positioning and navigation,offshore oil and gas resources exploration and underwater rescue.The underwater acoustic channel has wide and narrow band,strong and multi-path,and serious noise interference,which causes the received signal to distort and affect the performance of underwater acoustic communication system.Orthogonal Frequency Division Multiplexing(OFDM)technology is one of the implementation methods of multi-carrier transmission scheme,which has strong anti-multi-path interference ability and high data transmission rate,and has been widely used in underwater acoustic communication.Aiming at the problems of time-varying multi-paths and noise interference in underwater acoustic channels,this paper constructs a high-speed and reliable underwater acoustic communication system based on OFDM technology,and studies its security and efficiency.The underwater acoustic DE-OFDM communication system based on Speex is proposed,and the main research contents are as follows:(1)Research on Underwater acoustic OFDM communication algorithm based on dual encoding strategy(DE-OFDM).Channel convolution coding can increase the number of information bits by many times,and obtain coding bits by adding redundant information and restricting inter-information,so as to improve the anti-noise and timevarying multi-path interference performance of the communication system.Based on differential coding technology,the reference phase is constructed,and the symbol is encoded by the adjacent phase difference to effectively eliminate noise and time-varying multipath interference.Based on the actual underwater acoustic channel simulation experiment,the good experimental results verify the effectiveness of the communication system.(2)Conduct research on underwater acoustic DE-OFDM communication based on Speex to improve the safety and efficiency of underwater acoustic communication.The input information is encrypted based on RSA algorithm,and the plaintext is converted to ciphertext,which improves the security of underwater acoustic communication system.Information is compressed based on Speex algorithm,which reduces the amount of communication data,improves the rate of underwater acoustic communication,and realizes efficient underwater acoustic communication.Based on the actual underwater acoustic channel simulation experiment,the good experimental results verify the effectiveness of the communication system.(3)Field test under multi-water area.For the underwater acoustic DE-OFDM communication system based on Speex,the experimental tests of the water tank and Jiaozhou Bay are carried out,and the ultra-short range is 10 m,the short range is 1km,and the long range is 5.5km,all of which can be decoded correctly.The underwater acoustic communication test against time-varying multi-path interference and ship noise interference is carried out in the water tank.The test results verify that the communication system can realize reliable communication under strong multi-path interference and noise interference.The Jiaozhou Bay ocean test verifies that the communication system can realize ocean acoustic communication at different distances.The experimental results show that the underwater acoustic communication system has good application value.Based on OFDM technology,this paper proposes an underwater acoustic OFDM communication system based on dual coding strategy,and constructs a high-speed and reliable underwater acoustic communication system.On this basis,research is carried out on safe and efficient underwater acoustic communication based on RSA algorithm and Speex algorithm,and a underwater acoustic DE-OFDM communication system based on Speex is proposed.Theoretical analysis,simulation experiment and multi-water field test are all decoded correctly,and the test results verify the effectiveness of the communication system.