This is the first textbook which presents the theory of pure discrete communication systems and its relation to the existing theory of digital and analog communications at a graduate level. Based on the orthogonality principles and theory of discrete time stochastic processes, a generic structure of communication systems, based on correlation demodulation and optimum detection, is developed and presented in the form of mathematical operators with precisely defined inputs and outputs and related functions. Based on this generic structure, the traditionally defined phase shift keying (PSK), frequency shift keying (FSK), quadrature amplitude modulation (QAM), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) systems are deduced as its special cases. The main chapters, presenting the theory of communications, are supported by a set of supplementary chapters containing the theory of deterministic and stochastic signal processing, which makes the book
