基于子载波间干扰深度估计的MIMO-OFDM水声通信接收机

MIMO-OFDM Underwater Acoustic Communication Receiver Based on Intercarrier Interference Depth Estimation

多输入多输出正交频分复用(MIMO-OFDM)水声通信系统中,由于子载波间干扰(ICI)对信号的影响程度未知,导致接收处理时干扰消除不完全或计算复杂度高。针对这一问题,该文提出一种迭代的基于子载波间干扰深度估计的MIMO-OFDM接收机。该接收机使用导频频域相关对每个发射信号的子载波间干扰深度进行估计,信道估计时利用估计出的干扰深度重建各个信道的频域矩阵,避免对不同信道选择相同的干扰深度,在自适应信道变化的同时降低了计算复杂度。此外,将判决反馈均衡引入MIMO-OFDM水声通信系统,利用已均衡出的符号信息消除子载波间干扰。仿真结果表明,该接收机相比于干扰深度渐进的接收机,译码成功所需的时间更短。

Due to the unknown influence of Inter-Carrier Interference(ICI)on the signal in Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing(MIMO-OFDM)underwater acoustic communication systems,the receivers have problems with incomplete interference cancellation or high computational complexity.To solve this problem,an iterative MIMO-OFDM receiver based on ICI depth estimation is proposed.The pilot frequency domain correlation is used to estimate the ICI depth for each transmitted signal.In channel estimation,the frequency domain matrix of each channel is reconstructed by using the estimated interference depth,which avoids selecting the same interference depth for different channels.Therefore,the proposed receiver can self adapt to channel variations and reduce computational complexity.Furthermore,decision feedback equalization is introduced into the MIMO-OFDM underwater acoustic communication system,and the equalized symbols are used to eliminate ICI.Simulation results show that the correct decoding time of the proposed receiver is less than that of the ICI-progressive receiver.