i-user detection tech- niques, and software radio applications. Chapter 2 presents the fundamentals of system analysis, e.g. multiple access options, which considers narrow-band and wide-band digital channels, as well as the background for the UTRA FDD and TDD modes. It covers signal processing aspects describing the principles of spread spectrum, modulation and spreading, the CDMA performance, PN sequences, power control and handovers. It presents the communications environments envisaged for UMTS operation and deployment. It also describes the channel models used to verify and justify the performance for the selected operating scenarios. It pro- vides a summary of the mathematical formulation for the performance analysis results seen in the forthcoming chapters (e.g. Chapter 7). Chapter 3 describes the UMTS development platform. It introduces its architecture top down, identifying the core and access network domains. It defines the UTRA identifiers and functions, e.g. system access control, radio channel ciphering and deciphering, mo- bility functions, and radio resource management and control functions. It also presents mobility management with its signaling connections and impact of mobility handling. Chapter 3 presents the UTRAN sychronization and UTRAN interfaces besides pointing out co-existing 2G/3G network issues. It also introduces the radio interface protocol architecture with its structure in terms of services and function layers. This chapter thus outlines the most relevant elements, which require technical description for design and implementation. Chapter 4 describes the UTRA physical layer design and configuration, where we intro- duce all the building blocks in detail with their respective technical description and re- quirements. It covers dedicated common transport channels, configuration of FDD and TDD physical channels in the uplink and downlink with their spreading and coding characteristics. Spreading and modulation, including scrambling, multiplexing and channel coding are also discussed. 