Cellular networks are challenged by the limited spectrum available at microwave frequencies. In the past several years, various technologies have been proposed to achieve ultra-high levels of spectral efficiency involving the use of multiple antennas, serving multiple users, and shrinking cell sizes. Many of these technologies have significant potential but do not provide the high data rates due to the limited spectrum available. An alternative is to use the millimeter wave (mmWave) band between 3-300 GHz to provide high bandwidth communication channels. Realizing mmWave cellular communication, however, requires addressing the fundamental difference between mmWave and microwave communication. mmWave networks will require high gain directional antennas at the transmitter and receiver to overcome path loss at higher frequencies and to ensure sufficient signal-to-noise-ratio at the receiver. These directional antennas must be implemented using a combination of analog and digital signal processing techniques, due to power hungry mixed signal hardware. The cellular systems must be designed to support highly directional transmission and reception from their inception, and must also deal with the increased impact of signal blockages.
This research project will establish the potential of millimeter wave cellular networks by incorporating the key features and constraints of mmWave communication. To understand the potential of such networks, this project will develop mathematical tools to analyze the performance of large-scale millimeter wave cellular networks, explicitly incorporating directional antennas and blockages. To enable robust communication, this project will create communication strategies that are simultaneously suitable for the harsh millimeter wave propagation environment and the limited capabilities of millimeter wave hardware. To leverage potential coexistence with lower frequency signals, this project will investigate the design and analysis of a hybrid-access system that exploits the coexistence of microwave and mmWave cellular systems. A main theme in the research thrusts is to incorporate key features of mmWave communication into the algorithms and analysis.
Broader impacts of the project's theory, algorithms, and architectures are expected in diverse areas. The mathematical tools developed in this research will impact the design and realization of cellular networks with directional communication. The signal processing algorithms based on array processing and stochastic geometry will pave the way for a new understanding of millimeter wave wireless communication. Industry impact will occur through the Wireless Networking and Communications Group (WNCG) industrial affiliates incorporating the results of the research into their wireless networking technologies. The project will foster the training of graduate students in course projects and will reach out to the community through public demonstrations.
