This is the fourth edition of this successful professional reference book on transceiver design, the device that both sends and receives signals, and its place within the wireless communication system. It gives engineers and others a good intuitive understanding of wireless systems and spread spectrum. New topics covered include cognitive radio, systems, networks, and commercial communications. In addition, many items have been extensively updated to improve the flow of the book and enhance comprehension.The new edition provides more of the latest technologies that are vital to wireless communications with the addition of cognition and commercial wireless systems.The revision rounds out the areas in concept and development and most importantly, adds modern developments on the cognitive areas associated with adaptive technology that makes a system smart.