Performance analysis of banded equalizers for OFDM systems in time-varying channels

OFDM systems affected by severe time-varying channels greatly benefit from equalization schemes based on intercarrier interference (ICI) mitigation, which guarantee improved performance with respect to conventional one-tap equalizers. By exploiting a semi- analytical approach, this paper assesses the BER performance of the so-called banded equalizers, i.e., those equalizers that take into account only the ICI produced by the closest subcarriers. Specifically, by exploiting the Gaussian approximation of the residual ICI at the equalizer output, we evaluate the BER of block linear equalizers designed under a minimum mean-squared error (MMSE) criterion. Simulation results show a very good agreement with the theoretical analysis. In addition, we derive a lower bound and an approximate upper bound for the BER of block decision-feedback equalizers.