Effective Data Detection Algorithms for OFDM Systems over Time-Varying Multipath Fading Channels

For fast-fading time-varying channels, channel variations over an OFDM symbol destroy the orthogonality among subcarriers. The resulting intercarrier interference (ICI) degrades the system performance. The degradation becomes severer as mobile speed, carrier frequency, or symbol duration increase. In this work, based on the existing data detection methods, several modifications are proposed to improve the system performances and to reduce the computational complexity. The proposed methods effectively use frequency diversity provided by time-varying channels. As a result, the proposed techniques noticeably outperform the conventional methods, including the ICI cancellation method and zero-forcing (ZF) detection. For implementation, the proposed methods are modified to have acceptable complexity.