Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book discusses the fundamental principles of Intelligent Reconfigurable Surfaces (IRS)-aided communications and provides an analysis on the near-field region, wherein the channel modelling and phase shift design problems differ from those in the far-field. It explores the potential of deploying IRSs in merging non-terrestrial networks (NTNs). The book highlights how IRSs can be integrated in NTN to enable a typical mobile handset to directly communicate with satellites. It provides an overview of the general hardware architecture of IRS that opened a new platform to dynamically manipulate electromagnetic waves. The book explores channel modelling frameworks for facilitating a thorough and accurate evaluation of the system performance of IRS-aided communications operating in the millimetre wave and sub-6 GHz bands. It investigates the significant role that IRS will play in fifth-generation and sixth-generation wireless networks.