Title:  Ultra-Massive MIMO Communications in the Millimeter Wave and Terahertz Bands for Terrestrial and Space Wireless Systems

Committee:

Dr. Ragupathy Sivakumar, ECE, Chair , Advisor

Dr. Gordon Stuber, ECE

Dr. Manos Tentzeris, ECE

Dr. Chuanyi Ji, ECE

Dr. Ashutosh Dehnke, CS

Abstract: In wireless communication channels, electromagnetic waves are propagated in an uncontrolled manner with various alterations including reflections, diffractions, and scattering. These propagation phenomena notably affect the performance of wireless links. Existing techniques, such as small cells, have been developed to improve the spectral efficiency of wireless networks. However, they will be insufficient to keep up with the growing demand for a higher throughput with limited spectral resources in current cellular frequencies. The millimeter wave (mmWave) and terahertz (THz) frequency bands are hence envisioned as one of the key enabling technologies to achieve terabits-per-second (Tbps) links in next-generation wireless networks. Albeit having abundant spectral windows for wireless communications, these frequency bands are subject to limitations in transmission distance, due to the remarkably high path loss inherent to small wavelengths. The objectives of this Ph.D. thesis are to develop solutions to combat such distance limitation problem and analyze their performance in both terrestrial indoor and space communication scenarios. In particular, for indoor communications, a solution of Intelligent Communication Environments is designed based on the ultra-massive multiple-input multiple-output communications and recent advances in the two-dimensional metamaterials (i.e., metasurfaces), which allow active control of electromagnetic waves in wireless propagation environment to extend coverage at the mmWave and THz bands. In parallel to terrestrial communication use cases, the mmWave and THz bands are promising to realize ultra-high-throughput links for inter-satellite communication in small satellite networks. In this direction, a multi-band design of small satellites and a dynamic spectral resource allocation strategy are proposed. Moreover, the orbital perturbation factors and beam-pointing losses are characterized with a link-level performance analysis detailed in this thesis.