S UTRAN GPRS / EDGE packet switched Interactive / background Interactive / background bearers (with several time bearers slots in BSS) Streaming video UMTS UTRAN GPRS / EDGE packet switched Streaming QoS bearers Streaming bearers (with several time slots in BSS) Figure 5.26 Example of matching services and networks Understanding Changing Telecommunications - Building a Successful Telecom Business Business cases are suitable inputs to take decisions. For the expensive access network stepwise extensions give good results. Examples of stepwise approaches are GPRS and EDGE on the mobile side and the xDSL systems on the fixed side. UMTS also represents a step, since it complements GSM for established GSM operators, but the step is more expensive with new base stations. See Figure 5.27. Access External equipment network network networks GSM access UMTS access Intranet Extranet Internet Figure 5.27 UMTS can be regarded as a complement to GSM Remote subscriber stage Local exchange Radio switch Radio switch Figure 5.28 Access network shape for baseline investments Services Fiber Ethernet ADSL, VDSL, SHDSL, Access node Wireline packet ADSL Lite Multi-service packet access backbone network Access transport Modem FR, SDH Figure 5.29 Transport in the access network In 3G, the enhanced bandwidth capabilities and advanced terminals enable video and audio, either real time, near real time or download. Examples are two-way video con- ferencing with audio, video streaming, hi-fi music streaming and interactive games. The speed and quality of the service will enable new presentation formats. The need for new base stations is substantial when extending mobile systems to 3G, in view of the maximum coverage area radius: GSM 900 about 35 km, GSM 1800 about 8 km and UMTS cells about 5 km radius. About 10 years ago the fixed access network would have had the look of Figure 5.28. To be fair it must be pointed out that the figure is voice oriented. Thus, there were also dedicated and switched (X.25, frame relay, ATM) data accesses to the e