Time- and Frequency-Domain Impulsive Noise Spreader for OFDM Systems

Abstract

In this work, a new technique for mitigating the impulsive noise impact on the orthogonal frequency division multiplexing (OFDM) system is proposed, and its performance is compared with a previously published technique (referred to as time-domain interleaving (TDI) technique). In the TDI technique, the samples contaminated by impulsive noise are spread in timedomain over N OFDM symbols by using an interleaver after the inverse fast Fourier transform (IFFT) process. Accordingly, the effect of the impulsive noise burst will be averaged over N OFDM symbols, which reduces the impact on the bit error rate (BER) considerably. However, to achieve the same goal, the proposed system is using an additional orthogonal transform in form of an IFFT at the output of the interleaver. In general, the two techniques have shown a superior improvement in BER performance compared to that of the standard OFDM system, which suffers from error floors at high values of signal to noise ratio (SNR). However, for quadrature phase shift keying (QPSK) modulation with low signal to impulsive noise ratio (SIR), the proposed technique outperforms the TDI technique for different impulsive noise distributions. For high modulation order 16 and 64 quadrature amplitude modulation (QAM) in severe impulsive noise channels, the proposed technique demonstrates more robustness than the TDI, which suffers from error floors for the considered values of SIR and impulsive noise distributions.