The next generation of wireless standards are aimed at providing high speed communication to mobile users. Two of the most promising technologies that can dramatically increase the information rate without the increase of power or spectrum are those that exploit multiple antennas and finite-rate feedback from the receiver to the transmitter. The benefit of side information at the transmitter is significant in regimes that happen to fit the requirements of high speed downlink communication by mobile devices, where there are more transmit than receive antennas. Among the post Third Generation wireless technologies, most of them, such as WiMax, Super3G/LTE (Long Term Evolution), 802.11n, employ MIMO-OFDM technology. It is anticipated that this research will lead to methods for significantly increased spectral efficiencies in these technologies.
The proposed research is on wireless communications ranging from its fundamental underpinnings in information theory to the analysis and optimization of novel and practicable communication architectures that exploit a few bits of feedback per channel realization. Mechanisms exist for providing finite-rate feedback and methods by which the wireless channel fluctuations can be exploited with this feedback will be investigated. Because of the enormous potential of multi-antenna systems, the fundamental limits with finite-rate feedback, namely ergodic and outage capacities, will be characterized and low complexity methods with near-optimal performance will be designed and analyzed for multi-antenna (MIMO) communication for single- and multi-carriers (OFDM) systems. The nature of the problems which are at the heart of the proposed research demand collaboration across the fields of information theory, quantization, error-correction coding, random matrices and large deviation theory. This research is expected to also motivate new mathematical discoveries that are expected to find broader applications in other areas.
