MMSE turbo receiver for space-frequency bit-interleaved coded OFDM

This paper considers transmission of OFDM modulated signals over MIMO frequency-selective fading channels. To benefit from diversity, coding is introduced in the space and frequency dimensions by means of bit-interleaved coded modulation. Assuming the OFDM cyclic extension works properly, MIMO space equalization has to be performed for each individual tone. A set of low-complexity MMSE SISO equalizers, achieving both spatial-interference mitigation and demodulation, is used. This set of MMSE equalizers exchanges soft information with the SISO decoder according to the turbo principle. The performance of this scheme is illustrated by computer simulations for quasistatic frequency-selective channels. It is shown that this receiver is able to exploit space and frequency diversity.