ket Radio Service (GPRS) enables GSM with Internet access at high spectrum efficiency by sharing time slots between different users. It affords data rates of over 100 kbits/s to a single user while offering direct IP connectivity. Enhanced Data Rate for GSM Evolution (EDGE) modifies the radio link modula- tion scheme from GMSK to 8QPSK. Thereby increasing by three times the GSM throughput using the same bandwidth. EDGE in combination with GPRS (E- GPRS) will deliver single user data rates of over 300 kbits/s. UMTS as 3rd generation wireless technology utilizes a Wideband CDMA or TD/CDMA transceiver. Starting with channel bandwidths of 5 MHz it will offer data rates up to 2 Mbits/s. UMTS will use new spectrum and new radio network configurations while using the GSM core infrastructure. 1 For example WAP terminals. Including voice or IP as a new trend. 3 In the USA - TIP1, in Japan - ARIB, in Korea - TTA, and in China - CWTS. Evolving Mobile Networks 2000 k 1000 k Packet 100 k Circuit HSCSD Evolution Year Figure 1.2 Evolution for wireless networks4 e.g. GSM. Although the circuit switched enhancements such as HSCSD will increase transmission rates, it is packet switched enhancements, which will meet the challenges or demands posed on current wireless networks. Thus, GPRS and UMTS with EDGE as an interme- diate solution will provide the platform to support integrated services of voice and data including multimedia. While GPRS and UMTS meet the demands for Internet (IP) features and higher band- widths in mobile networks, another evolution step is taking place in the network infra- structure. This is the convergence of single networks into a multi-purpose backbone network. The next section covers this step, which will have also impact on the imple- mentation of UMTS radio access technology. 1.1.1 Convergence of Fixed and Mobile Networks Convergence, i.e. the closer interworking between fixed and mobile telecommunica- tions, although it has long been a buzzword in the telecom market, is now coming into reality. As Eric