  Asynchronous and cyclostationary impulsive noise can severely impact the
bit-error-rate (BER) of OFDM-based powerline communication systems. In this
paper, we analyze an adaptive nonlinear analog front end filter that mitigates
various types of impulsive noise without detrimental effects such as
self-interference and out-of-band power leakage caused by other nonlinear
approaches like clipping and blanking. Our proposed Adaptive Nonlinear
Differential Limiter (ANDL) is constructed from a linear analog filter by
applying a feedback-based nonlinearity, controlled by a single resolution
parameter. We present a simple practical method to find the value of this
resolution parameter that ensures the mitigation of impulsive without impacting
the desired OFDM signal. Unlike many prior approaches for impulsive noise
mitigation that assume a statistical noise model, ANDL is blind to the exact
nature of the noise distribution, and is designed to be fully compatible with
existing linear front end filters. We demonstrate the potency of ANDL by
simulating the OFDM-based narrowband PLC compliant with the IEEE standards. We
show that the proposed ANDL outperforms other approaches in reducing the BER in
impulsive noise environments.
