Chapter 1 has presented a window to perceive the environment into which UMTS 12 will develop. It has set the background to introduce UMTS Radio Access Technology, the aim of this book. From the impressive growth of GSM and the Internet, as well as the UMTS air-interface specification requirements, UMTS Terrestrial Radio Access (UTRA) is well positioned to play the key role in the convergence of telecommunica- tions towards integrated services. Therefore, the contents of future chapters describe in more detail some of key elements shown generically in this chapter. References Mehrotra, A. "Cellular Radio - Analog and Digital Systems", Ch1 Artech House, Nor- wood, MA, 1994. Young, W.R. "Advanced Mobile Phone Service: Introduction, Background, and Objec- tives", Bell System Tech. J., 58(1), 1979, 1-14. Macdonald, V.H. "Advanced Mobile Phone Service: The Cellular Concept", Bell System Tech. J., 58(1), 1979, 15-41. UMTS 22.01 Service Aspects - Service Principles. UMTS 22.25 Quality of Service and Network Performance. UMTS 22.05 Service Capabilities. [7] UMTS 33.20 Security Principles for UMTS. UMTS 22.15 Security and Charging. [9] UMTS 22.24 New charging and Accounting Mechanisms. [10] UMTS 22.70 Virtual Home Environment. [11] UMTS 22.71 Automatic Establishment of Roaming Agreements. [12] UMTS 23.05 Network Principles. [13] TG24 Requirements for Charging, Billing, Accounting, Tariffing. [14] UMTS 22.20 Service Management. [15] UMTS 22.25 Quality of Service and Network Performance. [16] Ericsson, Connection No. 2 June 1999. [17] TG32 UMTS - Radio Requirements. 12 In particular UTRA. The UMTS Network and Radio Access Technology [18] High Level Requirements Relevant for the Definition of the UTRA concept, v3.0.1, 1998- [19] Godara, L.C. "Application of Antenna Arrays to Mobile Communications", Part I: Per- formance Improvement, Feasibility, And System Considerations", Proc. IEEE, 85(7), 1997, 1031-1060. [20] Godara, L.C. "Application of Antenna Arrays to Mobile Communications, Part II: Beam- forming And Direction-of-Arri