Communication over Wireless Fading Channels: A Modern View

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

The design of efficient wireless communication systems relies on a deep understanding of the basic characteristics of the underlying channel. The most fundamental and unique characteristic of wireless channels is the random time-variation of the channel strengths, a phenomenon known as fading. Communication over fading channels has been a topic of study since the 60's. A very different view of the problem, however, emerges from recent research. The traditional view of fading is that it is a source of unreliability that has to be compensated for by various diversity techniques. The modern view is much more powerful and considers fading as a source of randomization from nature that can be exploited to get very significant capacity boost. The research project addresses several key problems within this modern paradigm. They will be centered around two areas: 1) opportunistic communication : the dynamic rate and power allocation over the dimensions of time, frequency, antennas and users so that transmission is done when and where the channel is strong; 2) multi-antenna communication: the use of multiple transmit and receive antennas to increase the number of degrees of freedom available for communication in richly scattered fading environments. The issues studied are focused on how the random fading can be exploited even in the face of channel uncertainty, and the interplay between the modern and traditional views of channel fading.