Block-Sparse Impulsive Noise Reduction in OFDM Systems—A Novel Iterative Bayesian Approach

摘要

Using a novel block iterative Bayesian algorithm (Block-IBA), this paper presents a new impulsive noise reduction method for OFDM systems. The method utilizes the guard band null subcarriers and data subcarriers for the impulsive noise estimation and cancellation. Unlike some other general OFDM transceivers which use time-domain interleaving (TDI) to cancel impulsive noise, we design a specific receiver for bursty impulsive noise channels that removes the delay due to TDI and saves memory space. The Block-IBA first estimates the variance and the transition matrix of Markov chain model for the impulsive noise. It then iteratively estimates the amplitudes and positions of the block-sparse impulsive noise using the steepest-ascent based expectation-maximization (EM), and optimally selects the nonzero elements of the block-sparse impulsive noise by adaptive thresholding. Numerical experiments show that the proposed receiver outperforms existing receivers under the block-sparse impulsive noise environment.