Joint Impulsive Noise and Narrowband Interference Mitigation in Time-Varying OFDM Communications

Abstract

In this letter, we develop a novel sparsity-aware framework to model and mitigate the joint effects of impulsive noise (IN) and narrowband interference (NBI) in the time-varying orthogonal frequency division multiplexing (OFDM) systems. Due to its Doppler shift sensitivity, the time-varying characteristic will degrade the performance of OFDM. After Doppler shift compensation, the algorithms for eliminating NBI and IN are proposed within the sparsity-aware framework for OFDM system. In particular, the proposed interference mitigation technique exploits the sparsity of NBI and IN in the frequency and time domains, respectively. The chirp-z transform combined with the least square method is first used to address the issue of NBI causing the spectrum leakage effect after OFDM demodulation. Furthermore, based on the OFDM measurements with NBI suppression, the turbo compressed sensing algorithm is performed to iteratively correct the estimate of the impulsive noise from the residual NBI interference and ambient noise. The extensive simulation results illustrate the superiority of the proposed processing method compared with the counterpart methods.