Performance Analysis and Optimization for Advanced Multi-Antenna Systems with Nonlinear Power Amplifiers

Millimeter-wave (30-300 GHz) and Terahertz-band communications (0.3-10 THz) are envisioned as key wireless technologies to satisfy the demand for Terabit-per-second (Tbps) links in the 5G and beyond eras. The very large available bandwidth in this ultra-broadband frequency range comes at the cost of a very high propagation loss, which combined with the low power of mm-wave and THz-band transceivers limit the communication distance and data-rates. This project envisions the 6G wireless communications as intelligent communication environments enabled by Massive MIMO platforms to increase the communication distance, data-rates, and transmission reliability at mm-wave and THz-band frequencies.

The Reconfigurable Intelligent Surfaces (RIS) have given rise to the emerging concept of intelligent communication environments. A RIS is a meta-surface equipped with integrated electronic circuits that can be programmed to alter an incoming electromagnetic field in a customizable way. It consists of a single- or few-layer stack of planar structures that can be readily fabricated using lithography and nano-printing methods. Each RIS unit is implemented by reflect-arrays that employ varactor diodes or other MicroElectrical-Mechanical Systems, and whose resonant frequency is electronically controlled.