Hybrid median-nulling scheme for impulsive noise mitigation in OFDM transmission

Orthogonal Frequency Division Multiplexing (OFDM) is a rapidly growing technology in digital communications. OFDM performance is degraded by impulsive noise which can be mitigated by introducing different non-linearity schemes at the OFDM receiver like clipping, nulling, hybrid clipping-nulling and replacement. Clipping and nulling are the simplest schemes. Hybrid clipping-nulling combines the advantages of both clipping and nulling and performs better than the other schemes. Replacement scheme defines the clipping level equal to the average of the transmitted signal and gives comparable results as hybrid clipping-nulling. This article reviews some impulsive noise mitigation schemes suggested in literature and proposes a new scheme, known as hybrid median-nulling, which clips the signal values at the level defined by median of the received signal samples. Simulation results show that the proposed scheme results in better signal to noise ratio and symbol error rate as compared to other schemes.