This book is about radio frequency (RF) transceiver system design for wireless communication systems. Most digital communications texts focus on the system design of the digital base-band rather than the RF section. The text is written for RF system design engineers as well as RFIC design engineers involved in the design of radios for digital communication systems. It is also appropriate for senior undergraduates and graduate students in electrical engineering. The text develops systematic design methods of RF receivers and transmitters along with a corresponding set of comprehensive design formulas. Attention is given equally to the analysis of the RF systems. The book is focused on mobile communication systems implemented in RF application specific integrated circuits (ASICs) but it is applicable to other wireless systems such as, for examples, WLAN, Bluetooth and GPS. It covers a wide range of topics from general principles of communication theory, as it applies to digital radio designs, to specific examples on the implementation of multimode mobile systems. It is assumed that the reader has a good RF background, basic knowledge of signal and communication theory, and fundamentals of analog and mixed signal circuits.