An Efficient Technique for OFDM Systems over Fading Channels Impaired by Impulsive Noise

In this work, an elegant interleaving process is used not only to mitigate the impact of bursty impulsive noise on the performance of orthogonal frequency division multiplexing (OFDM) systems but also to break bursty multipath fading channel errors. While, conventional OFDM systems implement the interleaving process in the frequency domain, the system proposed here uses a block interleaver of size N² samples in the time domain. As a result, time diversity has been exploited through the use of the interleaver by spreading the samples contaminated by impulsive noise over the impulse-free OFDM symbols and breaking the correlated behaviour of the multipath fading channel. Nevertheless, the results, given in this work, have shown that the performance of the proposed system depends on the kind of equalization process used. A serious degradation in the performance is noticed when zero forcing (ZF) equalizer is utilized. However, a simple and low complexity solution to improve the ZF equalizer performance is also proposed. On the other hand, utilizing a minimum mean square error (MMSE) equalizer demonstrates better performance than the ZF equalizer. The simulation results have confirmed the validity of the proposed system over different scenarios of the channels considered in this work.