ABSTRACT
The UMTS system, presented in Chapter 3, proposed for third-generation cellular networks in Europe is meant to provide enhanced spectral efficiency and data rates over the air interface. The objective for UMTS, known as WCDMA in Europe and Japan, is to support data rates up to 2 Mbps in indoor or small-cell outdoor environments and up to 384 Kbps in widearea coverage for both packet and circuit-switched data. The 3GPP, responsible for standardizing the UMTS system, realized early on that the first releases for UMTS would be unable to fulfill this objective. This was evidenced by the limited achievable bit rates and aggregate cell capacity in Release 99. The original agenda and schedule for UMTS evolution has been modified to meet these goals by gradual introduction of advanced radio, access, and core network technologies through multiple releases of the standard. This phased roll-out of UMTS networks and services also would ease the transition from second-to third-generation cellular for manufacturers, network, and service providers. In addition, to meet the rapidly growing needs in wireless Internet applications, studies initiated by 3GPP since 2000 not only anticipated this needed evolution but also focused on enhancements of the WCDMA air interface beyond the perceived third-generation requirements.
