Multiple-input multiple-output orthogonal frequency division multiplexing in fast fading channels

The increased data rates and reliability required to support emerging multimedia applications require new communications technology. We present results regarding two techniques used in high data rate transmission---orthogonal frequency division multiplexing (OFDM) the and multiple-input multiple-output (MIMO) scheme. The aim of this dissertation is to find efficient methods of providing reliable communication links using MIMO-OFDM under fast fading scenarios. Toward this end, both equalization and channel coding techniques are investigated.; Despite many advantages of OFDM, OFDM signals are very susceptible to the time-varying channel, which breaks the orthogonality between subcarriers, resulting in interchannel interference (ICI). The ICI increases an irreducible error floor in proportion to the normalized Doppler frequency. A New hardware efficient equalizer, the q-tap MMSE equalizer, is developed to reduce ICI in MIMO-OFDM signals. Using the fact that the energy of ICI is localized in adjacent subchannels, the complexity of frequency domain MMSE equalizer can be reduced significantly without much performance degradation.; New metrics applicable for both space-time convolutional code (STCs) and space-time bit-interleaved coded modulation (ST-BICM) are developed, in order to combine the channel coding schemes with the q-tap MMSE equalizer. Simulation results showed that, for both STCs and ST-BICM, new metrics and 3-tap MMSE equalizers provide 2--3 dB gains at 10 -5 bit error rate.