Decision-feedback receiver for quasi-orthogonal space-time coded OFDM with correlative coding over fast fading channels

We propose to apply the frequency-domain correlative coding combined with a modified decision-feedback (DF) detection scheme to effectively suppress error floors of space-time coded orthogonal frequency division multiplexing (ST-OFDM) systems over fast fading channels. OFDM is robust against frequency selective fading, but it is more vulnerable to time selective fading than single-carrier schemes. In quasiorthogonal ST-OFDM systems, channel variations introduce not only inter-carrier interference but also inter-transmit-antenna interference among different transmit antennas. Common ST-OFDM receivers usually suffer from an irreducible error floor. We provide models of ST-OFDM systems with correlative coding in time-varying fading environments and design a DF receiver. Simulation results demonstrate the effectiveness of the proposed scheme in mitigating the effects of time selective fading.