先验信息整合的OFDM快衰落信道感知估计  

Prior Information Based OFDM Fast Fading Channel Sensing Estimation

作　　者：张军[1] 

机构地区：[1]广东工业大学信息工程学院,广东广州510006

出　　处：《湘潭大学自然科学学报》2012年第3期43-47,共5页Natural Science Journal of Xiangtan University

基　　金：国家自然科学基金项目(60901027)

摘　　要：在OFDM系统中,如何对快时变信道进行准确估计,同时提高频谱利用率是一个极具挑战的问题.传统信道估计方法如最小二乘法和最小均方误差法均基于多径信道密集型假设,导致频谱利用率低下.本文在压缩感知的框架下,利用多径信道的稀疏特性同时整合前次OFDM块中所估计的多径位置信息,提出了一个新的OFDM快衰落信道估计方法.因为利用了信道稀疏性与多径位置信息,本文提出的方法克服了奈奎斯特采样率的约束,大幅度减少了精确估计信道对导频数的需求.仿真实验结果表明,与经典的压缩感知和最小二乘方法相比,该文方法不仅获得了更好的估计精度,而且大幅度地提高了信道的频谱利用率.Fast fading of propagating channels degrades the performance of Orthogonal Frequency Divi- sion Multiplexing{OFDM）systems. Traditional channel estimation methods such as least squares {LS） and minimummean square error [ MMSE} are based on the rich multipath assumption which leads to low fre- quency spectrumutilization. This paper addresses the problem of estimating a fast Rayleigh fading channel in Orthogonal Frequency Division Multiplexing {OFDM} systems. A new channel estimation technique using the recent methodology of compressed sensing （CS} is proposed. CS-based channel estimation incorporates the prior knowledge exploited from the previous OFDM block to improve the performance of estimator and reduce the number of pilots. Simulation results demonstrate the proposed scheme has better performance and a significant reduction of the number of pilots than the conventional methods.

关 键 词：信道估计 压缩感知 OFDM 频谱利用率 

分 类 号：TN929.5[电子电信—通信与信息系统]