Adaptive blind equalization of the time-and frequency-selective OFDM system based on the local approximation

Abstract

Time-and frequency-selective fades will largely degrade the performance of orthogonal frequency-division multiplexing (OFDM) systems because the former introduces the inter-carrier interference (ICI) and the latter attenuates the amplitude and blurs the phase of transmitted sequence. In this paper, by dividing a long OFDM block into a series of short segments in which the time variation is significantly small and can be neglected, the time-and frequency-selective channel is approximated as a set of linear time invariant (LTI) systems, and thus can be further equalized using the blind equalization schemes of LTI systems. The study shows the new blind equalization has an improved performance in canceling the effects of the time-and frequency selective fades.