Principles of Communications provides an introduction to the fundamental principles of communications. Basic mathematical background for system and signals, analog communication systems and modern digital communication systems are systematically introduced. Principles of Communications theory is been explained in an easy-to-understand way. Advanced topics in modern digital communications, especially related to wireless communications, have been conceptually explained, including forward error correcting codes, fading channels, OFDM, and CDMA. This book serves as the basis of communication system design, and as a way to quickly understand the principles of communication systems for those who do not major in communications. Its readership includes undergraduate and graduate level students in the field of Communications and research engineers at Communications companies.Contents- Preface, - History and Milestones of Communication Technology- Filtering of Random Processes and Signals- Analog Communications- Pulse Modulations and Digital Coding- Optimal Receiver of Digital Communication Systems- Passband Digital Transmission- Error Correcting Codes- Communications over Wireless in Fading Channels- Orthogonal Frequency Division Multiplexing- Spread Spectrum Communications and Code Division Multiple Access- References; Index