 of multimedia data. Due to the need to sup- port legacy interconnect options to the cell site for many years, Frame Relay remains an attractive option to maximize the efficiency of the Base Trans- ceiver Station (BTS) backhaul links. The key changes in the UMTS architecture are that The Network Subsystem (NSS) has moved to an efficient packet-based transport, using low-cost standard packet switches to route the call and signaling traffic. This also requires changes to the peripherals, such as the voice mail system, which now operates in a packet-based voice-transcoded (and thus higher voice quality) mode. Transcoding and data-interworking functions have moved to the periphery of the network, where it connects with other networks. In the future UMTS network, the functions required to control the mobile network are server based and the underlying broadband network carries out the switching functions, as shown in Figure 11-13. The core plat- forms are built upon a common hardware and software architecture, enabling functions to be distributed as required. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Future Enhancements and Services Chapter 11 Figure 11-13 Service Provider UMTS in the future. Telephony and Service IP Networks Mgmt. Circuit HLR, SLR Switch Gateway SIM-Server CAMEL Server Network Broadband Server Mgmt. Network Application Center Server BSC/RNC Server Corporate User Spectrum for UMTS WRC-2000 identified the frequency bands 1,885 to 2,025 MHz and 2,110 to 2,200 MHz for future IMT-2000 systems, with the bands 1,980 to 2,010 MHz and 2,170 to 2,200 MHz intended for the satellite part of these future systems. CDMA is characterized by high capacity and small cell radius, employing spread-spectrum technology and a special coding scheme. The capabilities of cdmaOne evolution have already been defined in standards. IS-95B provides Integ