星地通信中基于压缩感知的OTFS信道估计  

Channel Estimation of OTFS Based on Compressive Sensingin Satellite-Ground Communication

作　　者：邵凯[1,2] 聂芝荣 SHAO Kai;NIE Zhirong(School of Communications and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;Chongqing Key Laboratory of Mobile Communications Technology,Chongqing 400065,China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065 [2]移动通信技术重庆市重点实验室,重庆400065

出　　处：《电讯技术》2025年第2期214-222,共9页Telecommunication Engineering

摘　　要：针对低轨卫星星地通信高动态信道特点,采用正交时频空(Orthogonal Time Frequency Space, OTFS)调制方式,提出一种低导频开销、高精度的两阶段信道估计方法,实现对时延、多普勒频移和信道增益3个参数的精细估计。所提TP-CSIE(Two Phase Channel State Information Estimation)方案采用时域训练序列为导频结构,解决时延-多普勒(Delay-Doppler, DD)域嵌入式导频方案在高动态星地链路下导频开销过大的问题。由于DD域信道的固有稀疏性,OTFS信道估计问题被转化为稀疏信号的恢复问题。在算法第一阶段,选用稀疏信号恢复算法进行信道参数的初始估计,利用重叠相加法获得部分先验信息以提高压缩采样匹配追踪(Compressive Sampling Matching Pursuit, CoSAMP)算法的准确性。在算法第二阶段,设计增强型旋转不变子空间算法实现信道参数的准确估计。仿真结果表明,与现有方案相比,所提算法归一化均方误差性能约有7 dB性能的提升,误码率性能约有10 dB的提升。In view of the high dynamic channel characteristics of low Earth orbit(LEO)satellite-ground communication,a two-phase channel estimation method based on orthogonal time frequency space(OTFS)modulation is proposed.The proposed method achieves precise estimation of three parameters:delay,Doppler frequency shift,and channel gain with low pilot cost and high accuracy.The Two-phase Channel State Information Estimation(TP-CSIE)scheme adopts a time domain training sequence(TD-TS)as the pilot structure to solve the excessive pilot overhead problem of embedded pilot scheme in the delay-Doppler(DD)domain for the high dynamic satellite ground links.Due to the inherent sparsity of DD domain channels,the OTFS channel estimation problem is transformed into the recovery problem of sparse signals.In the first stage of the algorithm,the sparse signal recovery algorithm is chosen for the initial estimation of the channel parameters,and the overlapping addition(OLA)method is designed to obtain partial prior information for improving the accuracy of the compressive sampling matching pursuit(CoSAMP)algorithm.In the second stage of the algorithm,the enhanced rotationally invariant subspace algorithm is designed to realize the accurate estimation of channel parameters.The simulation results show that,the proposed algorithm has a normalized mean square error(NMSE)performance improvement of about 7 dB and a bit error rate(BER)performance improvement of about 10 dB,compared with existing schemes.

关 键 词：低轨卫星 星地通信 正交时频空(OTFS) 信道估计 压缩感知 

分 类 号：TN927[电子电信—通信与信息系统]