Linear precoding with low complexity MMSE turbo-equalization and application to the wireless LAN system

An improved turbo-equalization process is proposed for linear precoding with iterative decoding. Using recent results in turbo-equalization, we derive the equalization coefficients for an optimized preceding decoder thanks to the SINR criterion. The proposed method keeps a low complexity even with large size precoders and high order modulations. Theoretical and simulation results show that full diversity is achieved after three or four iterations over a flat Rayleigh fading channel. An application of this transmission scheme is presented in the context of the OFDM wireless LAN 802.11a. We observe a gain of several decibels compared to the conventional unprecoded transmission scheme.