Pre-diversity using coding, multi-carriers and multi-antennas

In this paper, we describe a prediversity (diversity at transmitter) scheme using coding, multi-carriers and multi-antennas designed for fading channels. Burst errors occur frequently in the Rayleigh flat fading mobile channel. To solve this kind of problem, the time interleaving technique has been utilized. However it can not deal with slow fadings, and has a long processing delay. Our proposal requires no time delay and provides a fixed BER characteristic not only for a slow fading but also for a fast fading channel. We derive an upper-bound for the BER. Through computer simulations, we show that the proposed system with (7,4) block code, 7-carriers and 7-antennas achieves 15 dB improvement in a slow fading channel (Doppler frequency f _D=10 Hz) compared with a time interleaving system. As another application, we apply the pre-diversity technique to normal MPSK post-diversity system using trellis code