高速移动通信系统中OTFS分数多普勒信道估计加窗研究

Study on OTFS Fractional Doppler Channel Estimation and Windowing in High-Speed Mobile Communication Systems

针对正交时频空间(OTFS)调制系统中分数多普勒信道对应的物理路径信道状态信息估计困难及计算复杂度较高等问题,该文提出一种节省导频资源的脉冲匹配滤波(PRS-PMF)信道估计算法。该算法首先使用数据与导频联合成帧的嵌入式辅助导频方法获得等效信道的估计,然后通过互相关匹配滤波估计出各路径信道状态信息,相比于传统的脉冲导频互相关匹配滤波信道估计算法,能够在降低计算复杂度的同时减少导频资源的占用。在此基础上,对OTFS系统加窗,减少窗口响应主瓣的整数样点数量并降低旁瓣电平,有效改善了等效信道多普勒响应函数的自相关特性,从而降低了其他符号及噪声对估计符号的干扰。

In the Orthogonal Time-Frequency Space(OTFS)modulation system,it is difficult to estimate the Channel State Information(CSI)of physical path corresponding to fractional Doppler channel,and the computation is very complicated.To solve these problems,a channel estimation algorithm PRS-PMF(Pilot Resource Saving-Pulse Matched Filtering)for pulse matching filter which saves pilot resources is proposed.In the algorithm,the embedded auxiliary pilot is employed to obtain the equivalent channel estimation,then the CSI of each path is estimated through the cross-correlation matched filter.Compared with the traditional crosscorrelation matched filter channel estimation algorithms,it can reduce the pilot resource occupy and the computational complexity.On this basis,the OTFS system is windowed to reduce the number of integer samples of the main lobe of the window response and reduce the side lobe level,which improves effectively the autocorrelation characteristics of the equivalent channel Doppler response function and thus reduces the interference of other symbols and noise on the estimated symbols.