基于OFDM的水声通信非一致多普勒补偿方法

Non-uniform Doppler compensation in underwater acoustic communication based on OFDM

当多径信道各径多普勒因子不一致时,传统的多普勒补偿技术会带来较大的残余误差。针对此问题,通过理论推导提出了一种针对水声多径信道存在非一致多普勒扩展的补偿方法。该方法采用多次内插与快速傅里叶变换相结合的算法,首先通过对接收信号进行单次重采样预处理以降低多普勒因子大小,再利用等效信道参数估计模型,获得信道统计量后进行正交频分复用解调,实现非一致多普勒补偿。仿真结果表明,所提方法在信道信息已知与未知的条件下,都具有较高的补偿性能,特别是在非一致多普勒扩展比较严重的情况下,其优势更加明显。

When there is different Doppler factors in each path of multi-path channel,the traditional Doppler compensation techniques will bring large residual Doppler spread.To solve the problem,a compensation method for non-uniform Doppler spread through a theoretical derivation is proposed,which uses multiple interpolation combined with the fast Fourier transform（FFT）algorithm.After a single resampling preprocessing aiming to reduce the size of the Doppler factor,an equivalent channel parameter model is considered.Further,to demodulate the orthogonal frequency-division multiplexing（OFDM）data,channel statistics are obtained by multiple interpolation and FFT.Numerical simulation results show that the proposed method has a high Doppler compensation performance both in known or unknown channel information.Especially when the non-uniform Doppler spread is serious,the performance of the method is much better than others.