CTH07-2: Design of Multi-Antenna Coded Modulators Using Noisy Quantized Channel State Information

Combining the benefits of diversity/coding gain from space-time coding and array gain from beamforming over quasi-static block fading channels is accomplished in a suitable way for erroneous feedback conditions. For this purpose, we utilize multi-dimensional space-time constellation sets or vector codes combined with linear precoders which are designed to minimize the error probability. Furthermore, the design of a feedback link based on maximum received signal-to-noise ratio criterion is considered. In practice, the transmitter channel state information is degraded by several factors in the feedback link, e.g. bandwidth limitation, delay, and noise which is the main problem. The defective information at the transmitter leads to drastic performance degradation unless the system is robustly designed against the feedback errors and mismatches. Therefore, we employ quantized feedback strategies optimized for noisy channels. The most attractive property of our scheme is that it converges to space-time coding in extremely poor feedback cases and to pure beamforming in relatively high quality feedback situations. Simulation results confirm the good performance of our scheme.