| 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. |
