Analysis and Enhancement of Directional Millimeter Wave and Terahertz Band Systems

The emergence of directional millimeter wave (mmWave) and terahertz (THz) communication systems is one of the major innovations introduced by the telecommunication industry in recent decades. First, the broad bands available in themmWave and THz spectrums promise an order of magnitude improvement in the data rates. Second, highly-directional transmissions offer better spatial diversity that facilitates the performance and security of next-generation communication systems. As a result, the directional communications over the mmWave and THz bands may effectively support novel applications and services, ranging from augmented reality to collective driving by the fleets of autonomous vehicles. Together with many advantages, mmWave and THz communications bring new challenges that require revisiting the conventional approaches to design and analyze wireless networks. The unique features of mmWave and THz signal propagation combined with the directionality of the links form a unique set of open research problems that were not as pressing at lower frequencies. In response, novel approaches, methods, and tools are needed to carefully model and evaluate the emerging mmWave and THz wireless systems. This thesis is targeted at developing a comprehensive set of mathematical frameworks and simulation tools capable of accounting for the essential features of directionalmmWave and THz wireless systems. The formulated models are then applied for constructing the first-order performance estimations of mmWave and THz communications operation in prospective usage scenarios. Later, on top of analyzing the state-of-the-art approaches for buildingmmWave and THz systems, the new technological enhancements to the advanced wireless networks operating in these bands are evaluated. The contributed frameworks and tools can be extended to model and assess the further developments in mmWave and THz communications