Robust OFDM in fast fading channels

Techniques for reducing interchannel interference (ICI) of orthogonal frequency division multiplexing (OFDM) systems under a fast fading channel are presented. Combined frequency domain equalization and bit-interleaved coded modulation (BICM) are investigated. Using the fact that ICI energy is concentrated in adjacent subchannels, the complexity of the frequency domain equalization can be significantly reduced without much performance degradation. New bit metrics for the BICM are derived to improve the performance when the frequency domain equalizer and BICM are used together. Computer simulation demonstrates the robustness of the suggested techniques even when the normalized Doppler frequency is higher than 0.1.