改进的信道稀疏度检测正交多载波多普勒估计方法

针对正交频分复用水声移动通信中频域变采样技术联合信道稀疏度检测的多普勒估计算法在冰水混合区复杂信道环境下多普勒估计效果欠佳且计算量大的问题,提出了一种改进的多普勒估计算法。采用时域重采样技术对信号进行不同压缩因子的补偿,避免了频域变采样技术中的高阶快速傅里叶变换运算,从而降低了算法复杂度。利用梳状导频位置向量结合时域变采样技术更准确提取的导频子载波,进而获得更加精确的信道估计和信道稀疏度检测结果,提高了多普勒估计精度。仿真结果和冰下试验结果表明,与原始算法相比,改进的方法在冰水混合水域复杂多径时变信道环境下可以有效实现对信号多普勒畸变的跟踪并且计算量显著下降,能够保障正交频分复用水声移动实时通信。 

An improved channel sparsity-based Doppler estimation method for underwater orthogonal frequency-division multiplexing

To overcome the disadvantages of Doppler estimation algorithm based on channel sparsity detection,an improved method is proposed to achieve better performance under ice-water mixed regions and reduce computational complexity.This algorithm utilizes time domain resampling technique to compensate the signal with different compression factors,which avoids the high-order fast Fourier transformation operation in the frequency-domain resampling technique,thereby reducing the complexity of the algorithm.The pilot subcarriers are extracted more accurately by combining the comb pilot position vector,thereby obtaining more accurate channel estimation and channel sparsity detection results,and improving the precision of Doppler estimation.The simulation results and under-ice experiments demonstrate that this improved algorithm is able to effectively track the doppler under ice-water mixed regions and reduce the computational complexity,ensuring the robust mobile orthogonal frequency division multiplexing communication.