OFDM水声通信CS限幅失真补偿与LS信道估计优化算法*

正交频分复用技术应用于水声通信系统时,会引起较高的峰均比,当采用限幅法对峰均比进行抑制时,会产生非线性失真。另外,系统采用最小二乘法进行信道估计受噪声的影响较大。针对以上问题,提出了一种基于压缩感知技术的补偿限幅非线性失真与最小二乘信道估计相组合的新算法,在接收端利用导频数据采用压缩感知算法对限幅失真进行补偿,同时对最小二乘信道估计进行优化运算,以减小噪声对其影响。理论分析和仿真结果均表明,新算法不但能够有效抑制限幅法造成的系统非线性失真问题,而且能够降低高斯白噪声对于信道估计的影响。

Optimization algorithm on CS clipping distortion compensation and LS channel estimation for OFDM underwater acoustic systems

Orthogonal frequency division multiplexing (OFDM) technology leads to a higher peak to average power ratio (PAPR) in underwater acoustic (UWA) channel. When the clipping method was used to restrain PAPR, the nonlinear distortion is produced. In addition, the least square (LS) method used is greatly affected by noise for channel estimation in the system. To solve the above problems, this paper proposes an optimization algorithm based on compression sensing (CS) about the nonlinear distortion of clipping and the noise of the LS method. Combined with CS algorithm, pilot data are used to reduce clipping noise in the receiver, and the LS channel estimation is optimized simultaneously. Theoretical analysis and simulation results indicate that the new algorithm can effectively restrain the nonlinear distortion for UWA communication systems. Moreover, the effect of Gaussian white noise on channel estimation can be reduced.