RIS-Assisted Wireless Systems

RISs have emerged as a promising technology for revolutionizing wireless communication systems. These intelligent surfaces, composed of passive elements, have the ability to manipulate and shape electromagnetic waves, enabling improved signal quality, enhanced coverage, and increased energy efficiency. This chapter introduces the RIS technology and provides an in-depth exploration of its concepts and principles. The benefits of RIS are discussed, highlighting its potential to realize future wireless communication systems. Furthermore, the chapter presents specific use cases for RIS in wireless systems, focusing on cognitive radio, unmanned aerial vehicles, and simultaneous wireless information and power transfer. To facilitate a deeper understanding of RIS-assisted systems, the chapter presents sample system models that operate in both half-duplex and full-duplex modes. These models serve as a foundation for the applications discussed in subsequent chapters of this book.