Mr. Wei Yu
Electrical Engineering Department
Stanford University, CA
Monday, April 29th, 11:00 AM, ENS 637
There are three main results in this talk. First, we show that in a Gaussian multiple access channel with multiple transmit and receive antennas, the optimum transmission strategy that maximizes the sum capacity can be found by an iterative water-filling procedure, where each user competitively maximizes its own rate. Thus, a competitive optimum in a Gaussian multiple access channel is also a global optimum. Second, we look at the long-standing non-degraded broadcast channel problem, and show that in a multi-antenna Gaussian broadcast channel, the sum capacity is achieved at a saddle-point of a mutual information game, where the transmitter chooses a transmit strategy to maximize the mutual information, and "Nature" chooses a fictitious noise correlation to minimize the mutual information. Thus, the sum capacity of a Gaussian vector broadcast channel corresponds to a competitive equilibrium. Third, we show that in a Gaussian interference channel, although a competitive optimum is not necessarily the global optimum, it leads to a desirable operating point.
Implications for practical wireless and wireline system design will be discussed. Several novel multi-user transmission and network optimization techniques will be presented.
A list of Telecommunications and Signal Processing Seminars is available at from the ECE department Web pages under "Seminars". The Web address for the Telecommunications and Signal Processing Seminars is http://signal.ece.utexas.edu/seminars