This paper presents a novel approach to mitigate the periodic impulsive noise before the synchronization of the orthogonal frequency-division multiplexing (OFDM)-based power-line communications (PLC) system. The proposed algorithm is employed to detect the periodic impulsive noise and then suppresses the periodic impulsive noise with an adaptive infinite impulse response (IIR) notch filter before the synchronization of the system, finally compensating the distortion of received signals brought by the IIR notch filter. Subsequently, the periodic impulsive noise mitigation algorithm is simulated and implemented in the PLC receiver's physical layer. Finally, the proposed algorithm is verified in field-programmable gate array and tested in the indoor PLC network. The simulation and field trial results show that the proposed periodic impulsive noise mitigation technique is simple and effective for the narrowband OFDM-based PLC system, such as the application of automatic meter reading.Index Terms-Adaptive infinite impulse response (IIR) notch filter, compensation, detection, orthogonal frequency-division multiplexing (OFDM), periodic impulsive noise, power-line communications (PLC).

Adaptive threshold compressive sensing (ATCS) algorithm using adaptive clipping threshold and compressive sensing (CS) has been proposed to mitigate the asynchronous impulsive noise in orthogonal frequency-division multiplexing (OFDM)-based power-line communications (PLC) system. Firstly, the impulsive noise is observed through projections onto the null subcarriers of OFDM, and estimated coarsely with the CS schemes. Then, the support (positions) of impulsive noise can be found with the adaptive clipping threshold based on the CS estimation. Finally, the MMSE estimator is adopted to estimate the amplitude of impulsive noise based on the estimated support. The estimated impulsive noise will be cancelled from the received data. The results of simulation and comparisons show that the proposed algorithm outperforms both MAP based CS technique and nonlinear techniques. The proposed ATCS algorithm is simple and effective, and it is suitable for the OFDM based communication systems.