Waveform Diversity for Wireless Communications with Joint Transceiver Multipath Exploitation and Interference Avoidance

Purdue University, West Lafayette IN

Investigators

Abstract

Multi-input multi-output (MIMO) wireless communication systems, equipped with multiple transmit and receive antennas, offer dramatically improved error performance and enhanced capacity. However, realizing the potential of MIMO systems is countered by the effects of fading, mobility, interference, and low-power requirements. The problem of interference is exacerbated by the proliferation of ad-hoc networks and the emergence of ultra-wideband communications. Existing approaches to MIMO wireless transceiver design assume either perfect channel knowledge or no channel knowledge at the transmitter. The latter yields pessimistic designs, while the former is unrealistic and can result in substantial performance losses in cases of severe channel mismatch. Thus, the researchers are investigating the fundamental capacity and error performance limits of MIMO wireless systems for varying degrees degrees of PARTIAL channel knowledge. Correspondingly, they are developing channel-adaptive MIMO transceivers based on partial channel knowledge that minimize transmit-power and maximize data rates at a prescribed error probability margin. Hybrid schemes are being researched that incorporate both space-time block coding and space-time beam forming to effect interference avoidance and robustness to imperfect channel knowledge. The advanced algorithms under development will profoundly alter MIMO technology and directly impact the robustness and bandwidth efficiency of wireless multi-antenna communications.