Research on Low Complexity Underwater Acoustic Multiple Input Multiple Output Orthogonal Time Frequency Space Modulation Communication Method
In the Multiple Input Multiple Output Orthogonal Time Frequency Space(MIMO-OTFS)underwater acoustic communication system,MIMO-OTFS communication based on the Message Passing(MP)algorithm have problems with high computational complexity,which may increase equipment costs in practical applications.To solve this problem,an MIMO-OTFS equalization algorithm based on two-dimensional Virtual Time Reversal Mirror(VTRM)is proposed,which uses the time-frequency-space focusing characteristics of VTRM to effectively improve the equalization performance.The channel estimation is performed using the Improved two-dimensional Proportional Normalized Least Mean Square(IPNLMS)algorithm,which utilizes the sparse characteristics of the time-delay Doppler domain channel to improve convergence speed at a lower computational complexity.Finally,residual inter-symbol interference is eliminated and system performance is further improved through the use of the two-dimensional adaptive decision feedback equalization algorithm.The simulation results demonstrate the feasibility of the proposed equalization algorithm,and show that it has lower complexity than the MP algorithm while ensuring the same performance.
Underwater acoustic communicationOrthogonal Time-Frequency-Space(OTFS)modulationVirtual Time Reversal Mirror(VTRM)Multiple Input Multiple Output(MIMO)