am, and the Internet is widespread not Mobile Internet Figure 1.1 The growth of mobile and internet services. The UMTS Network and Radio Access Technology only in the corporate environment but also in households. Large number of consumers have embraced the Internet and use it today to access information online, for interactive business transactions, and e-commerce as well as electronic mail. Figure 1.1 illustrates the growth in mobile and Internet subscribers. The success of mobile communications, i.e. the ubiquitous presence it has established and the emergence of the Internet point towards a tremendous opportunity to offer inte- grated services through a wireless network. One of the main market segments for wireless services besides corporate intra- net/internet access is the consumer sector. The availability of intelligent terminals or multipurpose wireless telephones is already ushering a new era of the information age, where subscribers can receive directly through GSM-SMS: news, sport updates, stock quotes, etc. However, the progress of audiovisual techniques and the support for a Web- like interface in a new generation of terminals, will push consumers to a new era of multimedia communications with a focus on services rather than technology. To support the growth of Internet type services and future demands for wireless ser- vices, ETSI SMG and other standards bodies have completed or are now completing specifications to provide a transition platform or evolution path for wireless networks like GSM. Figure 1.2 illustrates the wireless data technology options. The technology options in Figure 1.2 can be summarized as follows: 14.4 kbits/s allows GSM data calls with a rate of 14.4 kbits/s per time slot, resulting in a 50% higher data throughput compared to the current maximum speed of 9.6 kbits/s. High Speed Circuit Switched Data (HSCSD) aggregates symmetrically or asym- metrically several circuit channels, e.g. 28.8 kbits/s for two time slots (2 + 2) or 43.2 kbits/s for three time slots (3 + 1). General Pac