Title: Capacity Limits of Wireless Channels with Multiple Antennas: Challenges, Insights, and New Mathematical Methods
Speaker: Andrea Goldsmith, Stanford University
Date: Thursday, April 24, 2003 4:30-5:30pm
Location: CAIP Seminar Room, Room 601 CoRE Bldg., Rutgers University, Busch Campus, Piscataway, NJ
Wireless systems of the future must support ubiquitous multimedia communications between people as well as devices. There are many research challenges associated with such systems, including limited bandwidth, random variations in the wireless channel, and battery constrants in small radio transceivers. Many of these challenges can be overcome with multiple antennas at the transmitters and receivers of the wireless network, since these antennas both increase data rate and reduce channel randomness. However, traditional methods for determining Shannon capacity fail for channels with multiple antennas, especially when there are multiple users, channel variations over time, or channel memory. We present several new mathematical techniques to study Shannon capacity of multiantenna wireless channels with these properties, including duality, dirty paper coding, and Lyapunov exponents for products of random matrices. These techniques not only provide solutions to open problems in Shannon capacity, but also yield much insight into the optimal transmission strategies that achieve these capacity limits.