Nonlinear MMSE Equalizer for Impulsive Noise Mitigation in OFDM-Based Communications

Destructive effects of impulsive noise has been broadly observed not only in wireless communication systems but also in power-line communications. Impulsive noise is a common impediment in orthogonal frequency division multiplexing (OFDM) based communication systems for industry applications. This non-Gaussian noise degrades the performance of conventional equalizers and, hence, elicit a modified version of the equalizer that fits the non-Gaussian description of the noise. This letter proposes a nonlinear minimum mean square error equalizer for OFDM systems where the characteristics of the added noise to the system is known. The soft values were obtained based on the derivation of the equalizer for a memory-less channel impaired with impulsive noise. Obtaining such values are required for the implementation of a turbo-equalization scheme. The validity of such an equalizer is tested through simulations and the result of simulations shows that the nonlinear equalizer is successful in combating the effect of an impulsive noise. Thus, the turbo-coded OFDM system shows a significant boost at low signal-to-noise ratios.