BER reduction of OFDM based broadband communication systems over multipath channels with impulsive noise

This paper presents an efficient technique to jointly mitigate the severe bit error rate (BER) performance degradation caused by impulsive noise (IN) and multipath fading in broadband transmission systems. The proposed system is based on a low complexity interleaving process applied after the inverse fast Fourier transform (IFFT) in orthogonal frequency division multiplexing (OFDM) systems, hence it is denoted as time-domain interleaving (TDI). The proposed TDI introduces both time and frequency diversity, which can be used to effectively combat impairments such as IN and frequency-selective fading. In addition to its substantial BER reduction capability, the TDI does not degrade the spectral efficiency and has low computational complexity. In frequency-selective fading channels, the BER of the proposed system is mathematically equal to that of Walsh-Hadamard precoded OFDM systems. In presence of IN, analytical and simulation results show that TDI can remarkably reduce the level of the error floors that are commonly observed. Specifically, TDI can achieve a BER of 10^-5 for less than 1 dB difference from the IN-free case.