Modern Communications Systems is a senior-level introduction to communications systems, although it can also serve as a reference for graduate students and practicing engineers. It includes treatments of wireless and cabled transmission, cellular systems, and analog and discrete modulation and coding techniques. Examples include Wi-Fi, 4G and 5G cellular systems and DSL. Multicarrier and MIMO communication systems are also covered. All of the mathematics needed is included where it is used rather than in an early introduction, which makes it easier to follow. An extensive number of end-of-chapter problems, along with summaries of concepts, formulas and terms presented in each chapter, are included. Solutions to the end-of-chapter problems are available to instructors teaching from the book.