tailieunhanh - Các mạng UTMS và công nghệ truy cập vô tuyến P9

TOWARDS IP BASED NETWORKS BACKGROUND In the preceding chapters we covered UMTS in the context of the 3GPP Release 99 specifications. This chapter covers the forthcoming releases of UMTS, primarily Release 4 and 5 formerly Release 00. However, before we describe the reference architecture we outline the vision of the UMTS technical specification evolution from Ref. [1]. | The UMTS Network and Radio Access Technology Air Interface Techniques for Future Mobile Systems Jonathan P. Castro Copyright 2001 John Wiley Sons Ltd Print ISBN 0-471-81375-3 Online ISBN 0-470-84172-9 Û Towards IP Based Networks Background In the preceding chapters we covered UMTS in the context of the 3GPP Release 99 specifications. This chapter covers the forthcoming releases of UMTS primarily Release 4 and 5 formerly Release 00. However before we describe the reference architecture we outline the vision of the UMTS technical specification evolution from Ref. 1 . The UMTS Release 99 and Medium Term Architecture Release 99 RAN Release 99 Figure illustrates the service drivers of the UMTS architecture for R99 and future releases starting with R00. The latter has now been broken into Release 4 and 5. Added feature to R99 for later Releases External IP Networks IP Multimedia Subsystem CS Domain PS Domain Figure Release 99 and medium term architecture. The service drivers for R99 based on Ref. 1 include compatibility with GSM access to high-speed data services and managed QoS. The CS domain provides circuit-oriented services based on nodal MSCs an evolved GSM while the PS domain provides IP-connectivity between the mobiles and IP networks an evolved GPRS . Release R4 and R5 The medium term vision starting R4 and R5 has the added feature of IP multimedia as illustrated in Figure . The service drivers include compatibility with Release 99 addition of IP-based multimedia services and an efficient support of voice-over-IPover-radio for the multimedia service but not necessarily fully compatible with the telephony service and its supplementary services. 318 The UMTS Network and Radio Access Technology The CS domain retains and provides 100 backwards compatibility for R99 CS domain services. We can implement this domain through the evolution of MSCs or MSC servers and a packet backbone. The PS domain also retains and provides IP .