Combining Beamforming and Space-Time Coding Using Quantized Feedback

We combine space-time coding and transmit beamforming over multiple-antenna quasi-static fading channels using resolution-constrained channel state information at the transmitter (CSIT). The combining is performed using a class of constellation sets inspired from orthogonal designs and directional beamforming or in general, unitary precoding with quantized feedback. This constellation class is called partly orthogonal designs (PODs). The conventional way of using quantized feedback at the transmitter is through precoded space-time block codes (PSTBCs) that provide full-diversity order with all system configurations in terms of the number of feedback regions and the number of transmit antennas. PODs maintain the same advantage. However, they require less decoding and quantization complexity compared to PSTBCs. We develop PODs for transmission over multiple-antenna channels, analyze their performance, and optimize their structures based on pairwise error probability analysis. PODs creat...

• Type: Journal
• Year: 2008
• Where: TWC
• Authors: Siavash Ekbatani, Hamid Jafarkhani
• Keywords: Beamforming, Orthogonal Designs, PODs, TWC 2008