OFDM水声通信系统LS-DFT信道估计算法

对于正交频分复用(orthogonal frequency division multiplexing, OFDM)水声通信系统，频域最小二乘(least square, LS)信道估计算法受噪声影响较大，离散傅里叶变换(discrete Fourier transform, DFT)插值算法引入了由于空载波所产生的误差。针对上述问题，提出了一种LS-DFT信道估计算法，先对导频子载波进行LS信道估计，再通过DFT作降噪处理，然后通过误差对比和数据替换，得到一组新的导频信道估值，最后通过线性插值获得数据子载波处的信道估值。理论分析和仿真结果均表明，该算法能以较小的复杂度有效提升系统的性能。

LS-DFT channel estimation algorithm for underwater acoustic OFDM systems

For orthogonal frequency division multiplexing (OFDM) underwater acoustic (UWA) communication systems, the least square (LS) channel estimation algorithm is greatly influenced by the noise, and a new error is introduced due to null subcarriers for the discrete Fourier transform (DFT) interpolation algorithm. In view of the above problems, an LS-DFT channel estimation algorithm is proposed. First，the pilot channel estimation is done by the LS algorithm. Secondly, the above data are calculated through the DFT for noise reduction processing. After that, the data replacement is finished, and a group of new pilot channel data is acquired. Finally, linear interpolation is used to get a valuation in the other data subcarrier channel by the new pilot data. The theoretical analysis and computer simulation results show that the algorithm can effectively improve the performance of the system with a lower complexity.