Research On Underwater Acoustic Communication Receiver Technology Based On Efficient Spatial And Temporal Processing

Underwater acoustic channels have serious multi-path expansion and strong background noise,it is difficult to obtain sufficient signal-to-noise ratio for single-output channel receiver,and the computational complexity of conventional multi-output channel receiver increases significantly with the increase of the number of input channels.At the same time,the communication signal will experience a serious broadband Doppler effects.The narrow-band Doppler compensation method based on the adaptive phase-locked loop technology can only compensate for the limited carrier phase variation,and cannot compensate for broadband Doppler effects(e.g.the contraction or expansion of waveform)caused by the high-speed relative motion of sonar platform.In order to solve the above problems,this paper studies the technology of underwater acoustic communication receiver based on effective spatial and temporal processing technology and broadband Doppler compensation technology,combined with Turbo iterative equalization.Firstly,the mobile single carrier receiver based on spatial and temporal processing technology is studied.For single channel received signals,a broadband Doppler compensation linear iterative equalization receiver based on channel estimation which combined with a broadband Doppler compensation linear equalization receiver based on channel estimation and soft in/soft out(SISO)Turbo iterative equalization are studied.For the multiplex received signals,a spatial and temporal processing receiver based on adaptive broadband Doppler compensation technology is studied.The receiver uses spatial and temporal processing to reduce the processing complexity under the premise of ensuring performance.In order to reduce the bit error rate of the receiver,an iterative channel estimation linear equalization spatial and temporal processing receiver based on broadband Doppler compensation is proposed.The receiver combines SISO-Turbo iterative equalization technology with linear equalization spatial and temporal processing technology to achieve multi-channel robust communication.Then,direct sequence spread spectrum spatial and temporal processing receiver technology is studied.A spatial and temporal processing receiver based on symbolic decision feedback equalization algorithm is proposed for communication systems with relatively stable channel conditions.The receiver updates the system parameters at symbol rate and has less complex.In order to reduce the bit error rate of the receiver,a spatial and temporal processingreceiver based on symbolic decision feedback equalization using SISO-Turbo iterative equalization algorithm is proposed.For the communication system with fast channel change,a spatial and temporal processing receiver based on the hypothesis-feedback equalization algorithm is studied.The receiver acquires a hypothetical chip sequence by assuming transmitted symbol and updates parameters at chip rate.Finally,experimental data processing and simulation analysis.The effectiveness of the mobile single-carrier receiver studied in this paper is verified by the linear array test data and the distributed receiver array test data.The experimental results show that the studied mobile single carrier receiver includes the effective spatial and temporal processing technique and the broadband Doppler compensation structure can effectively obtain the spatial gain from multiplex received signals and compensate broadband Doppler effects.Thereby,underwater acoustic communication between high speed mobile platforms is realized.The simulation data is used to verify the effectiveness of the receiver based on direct spread spectrum spatial and temporal processing.The simulation results show that the hypothetical decision feedback equalization receiver studied in this paper can track the channel variation under time-varying channel and extract the spreading gain under the long spreading sequence.