roc. Multiaccess, Mobility and Teletraffic for Personal Communications Workshop, MMT'97, Melbourne, 1997. [12] Zander, J. "Radio Resource Management - An overview", Proc. IEEE Vehicular Technol- ogy Conf., VTC 96, Atlanta, GA, 1996, pp. 661-665. [13] Chen, L., et al, "A Dynamic Channel Assignment Algorithm for Asymmetric Traffic in Voice/Data Integrated TDMA/TDD Mobile Radio", Int. Conf. on Information, Communi- cations and Signal Processing ICICS'97, 1997, pp. 215-219. Mihilescu, C., Lagrange, X. and Godlewski, Ph. "Dynamic Resource Allocation in Locally Centralized Cellular Systems", Proc. IEEE Vehicular Technology Conf., Ottawa, 1998, pp. 1695-1700. [15] Huang, C.Y. and Yates, R.D. "Call Admission in Power Controlled CDMA Systems", VTC'96, 1996. [16] Zander, J. "Performance of Optimal Power Control in Cellular Radio Systems", IEEE Trans Vehic. Tech., 1, 1992. [17] 3GPP Technical Specification 25.101 UE Radio Transmission and Reception (FDD). [18] Ericsson, Tdoc SMG2 UMTS-L1 101 / 98, UTRA FDD Guard Band Analysis, 1998. [19] Hess, G.C. Land-Mobile Radio System Engineering, Artech House, Norwood, MA, 1993. [20] Yang, S.C. "CDMA RF System Engineering," Artech House, Norwood, MA, 1998. 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 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 Re- lease 4 and 5 formerly Release 00. However, before we describe the reference architec- ture we outline the vision of the UMTS technical specification evolution from Ref. [1]. 9.1.1 The UMTS Release 99 and Medium Term Architecture 9.1.1.1 Release 99 Figure 9.1 illustrates the service drivers of the UMTS architecture for R99 and future releases starting with ROO. The latter has now been broken into Release 4 and 5. Added feature to R99