一种改进的稀疏多径信道盲辨识算法

An Improved Blind Channel Identification Algorithm for Sparse Multi-path Channels

  • 摘要: 针对无线多径稀疏信道,利用信道有效近似思想,提出了一种改进的基于矩阵外积分解的信道盲辨识与盲均衡算法。算法首先利用改进的VIA信道阶数估计准则,对多径稀疏信道“有效部分”的阶数进行精确估计,然后利用改进的矩阵外积分解算法估计出信道冲激响应的“有效部分”,最后利用该估计结果对接收数据进行反卷积运算,恢复出发送信号。为了降低噪声以及信道冲激响应中的“零抽头”部分对信道盲辨识性能的影响,本算法对噪声方差估计方法进行了改进,提高了算法在中、低信噪比条件下的盲辨识性能。与现有算法相比,本算法不仅降低了对信噪比的要求,而且克服了基于LC准则的子空间算法(SSA, Subspace Algorithm)的相位偏转问题,其中噪声方差的估计方法也可应用于信噪比估计技术。仿真实验以及对SPIB微波信道测试结果验证了本文算法的有效性。

     

    Abstract: Based on the idea of the effective approximation, this paper uses the matrix outer-product decomposition and proposes a new blind identification and blind equalization algorithm to solve the sparse multi-path channel (SMC) problem in the wireless communication. Firstly, an improved VIA principle is adopted to precisely estimate the order of the effective part of the SMC. Then the channel coefficient of the effective part is estimated with the improved matrix outer-product decomposition. Finally, based on the results of the estimation, the received signal is deconvoluted so that the transmitted signal is derived. In order to eliminate the interference of the noise and the zero-taps (ZT) in the channel impulse response, this paper adjusts the noise variance estimation method so that the performance of the blind identification is improved when the signal-to-noise ratio (SNR) is low. Compared to the existing method, the algorithm proposed relaxes the SNR requirement of the estimation, and overcomes the phase distortion problem in Subspace Algorithm(SSA) which is based on the LC(Liavas’ Criterion), and the noise variance estimation method in the algorithm can also be used in SNR estimation techniques. The validity of the proposed method is verified via numerical simulations and the test results on SPIB microwave channel.

     

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