OFDM系统双选择性慢衰落信道的压缩感知估计  

Compressed Sensing Based on Doubly-selective Slow-fading Channel Estimation in OFDM Systems

作　　者：叶新荣[1,2] 朱卫平[1] 张爱清[1,2] 孟庆民[1] 

机构地区：[1]南京邮电大学信号处理与传输研究院,南京210003 [2]安徽师范大学物理与电子信息学院,芜湖241000

出　　处：《电子与信息学报》2015年第1期169-174,共6页Journal of Electronics & Information Technology

基　　金：国家自然科学基金(61372122);江苏省普通高校研究生科研创新计划(CXZZ11-0397)资助课题

摘　　要：为了增强压缩感知框架里0Sl(Smoothed 0l-norm)重构算法的抗噪性能,该文在其目标函数里添加一个误差容允项,并提出了一种改进型重构算法2 0l-Sl(Smoothed 0l-norm regularized least-square)。另外通过对多径信道的时延和多普勒频移参数构成的时频2维有界区域进行量化,将OFDM时频双选择性慢衰落信道估计问题建模为压缩感知理论中的稀疏信号重构问题,提出了一种采用2 0l-Sl估计信道时频参数的方法。仿真结果表明在相同的噪声环境里,2 0l-Sl的重构性能优于0Sl10 d B左右;运用2 0l-Sl的信道估计方法可获得接近于理想最小二乘法的估计性能,且该方法在低信噪比的场景里也能获得较高的估计准确度。In order to improve the reconstruction accuracy of smoothed 0l-norm（0S l） algorithm in the presence of noise, a modified algorithm named smoothed 0l-norm regularized least-square（2 0l-S l） is proposed in this paper, which permits a small perturbation. Further, through placing a finite grid in the planar time-frequency bounded region, the problem of doubly-selective slow-fading channel estimation in OFDM system is modeled as the problem of sparse signal reconstruction in compressed sensing framework, and then the 2 0l-S l algorithm is applied to reconstruct the channel parameters. A number of computer-simulation-based experiments show that reconstruction accuracy of the 2 0l-S l algorithm is improved by approximately 10 d B as compared with the 0S l algorithm in the presence of noise. The performance of the proposed doubly-selective slow-fading channel estimation method using 2 0l-S l algorithm is nearly close to that of the ideal Least Square（ideal-LS） method. Moreover, the proposed method has higher estimation uccuracy well in the case of low SNR.

关 键 词：压缩感知 OFDM 慢时变信道 信道估计 

分 类 号：TN92[电子电信—通信与信息系统]