低复杂度的OFDM信号信噪比的盲估计  

Blind SNR Estimation Scheme for OFDM Signals with Low Complexity

作　　者：李兵兵[1] 曹超凤[1] 刘明骞[1] 曾华阳[1] 

机构地区：[1]西安电子科技大学综合业务网理论与关键技术国家重点实验室,陕西西安710071

出　　处：《四川大学学报（工程科学版）》2012年第3期159-163,共5页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(60772138);国家高技术研究发展计划资助项目(2007AA01Z288);高等学校学科创新引智计划资助项目(B08038)

摘　　要：针对非合作通信系统中,多径信道下传统的正交频分复用(OFDM)信号信噪比盲估计方法的估计性能差,计算复杂度高的问题,提出了一种低复杂度的OFDM信号信噪比盲估计方法。该方法首先根据接收到的观测信号建立自回归(AR)模型,通过AR模型估计出信号的功率谱,然后基于高阶累积量的2阶和4阶的组合特征量与寻求跳变值的方法相结合估计出信号的带宽,最后通过计算出带宽之内的信号总功率和带宽之外的噪声功率估计出接收信号的信噪比。实验仿真结果表明,作者提出的方法无需任何先验信息,在多径信道下具有良好的估计性能,且计算复杂度低,更适合于实时的非合作通信系统。The traditional blind signal to noise ratio（SNR） estimation algorithms for orthogonal frequency division multiplexing（OFDM） signals have the problems of poor performance and high computation complexity in low SNR and multi-path channel conditions.In order to treat these problems,a novel blind SNR estimation method for OFDM signals was proposed.Firstly,the AR model was established to estimate the power spectrum of the received observed signal.Secondly,the bandwidth was estimated by using second-order and fourth-order cumulants combined characteristic quantity and with jump edge extraction method.Finally,the SNR was estimated by calculating the in-band total power and the out-band noise power.The simulation results showed that the proposed method do not need any prior information and have better performance and lower computation complexity,which is more suitable for real-time non-cooperative communication systems.

关 键 词：正交频分复用(OFDM) 信噪比估计 带宽估计 高阶累积量 空载波 

分 类 号：TN911.7[电子电信—通信与信息系统]