roadband data, whereas traditional 2G mobile systems were built mainly for speech service. The main improvements of 3G systems compared with 2G are [HT04]: Much higher peak data rates X. Li, Radio Access Network Dimensioning for 3G UMTS, DOI 10.1007/978-3-8348-8111-3_2, Vieweg+Teubner Verlag | Springer Fachmedien Wiesbaden GmbH 2011 2 UMTS Evolution Variable data rates to allow bandwidth on demand Support of asymmetric data rates on uplink and downlink to transfer packet- switched traffic, e.g. web browsing, ftp download/upload Provisioning of Quality of Service (QoS) for various applications and services, e.g. guaranteed error rates and delays Support of QoS differentiation, e.g. between delay-sensitive real-time services and best-effort packet data High spectral efficiency The air interface of UMTS is based on Wideband Code Division Multiple Access (WCDMA) technology that utilizes the direct-sequence spread spectrum method of asynchronous code division multiple access to achieve higher speeds and support more simultaneous users compared to the implementation of Time Division Multiple Access (TDMA) and Frequency Division Multiple Access (FDMA) used by the 2G GSM networks. Within 3GPP, WCDMA is called Universal Terrestrial Radio Access (UTRA). It has two modes of operation, namely UTRA-FDD (Frequency Division Duplex) and UTRA-TDD (Time Division Duplex). UTRA- FDD uses paired frequency bands for Uplink (UL) and Downlink (DL) data transmissions, whereas UTRA-TDD uses a common frequency band for both directions and adjusts the time domain portion assigned for UL and DL transmissions dynamically. In this thesis, only the UTRA-FDD mode is considered. In 1999 the 3GPP produced the first version of the WCDMA standard, which is the basis of UMTS deployed in most of the world today. This release, called Release 99, contains all the basic elements to meet the requirements for IMT-2000 technologies. As WCDMA mobile penetration increases, it requires UMTS networks to carry a larger share of packet data traffic. Thus 3GPP Rel