TABLE OF CONTENTS In Chapters 8 12, HSPA and the evolution thereof were described. As explained in these chapters, HSPA is an evolution of WCDMA, building upon the basic WCDMA structure and with a strong requirement on backwards compatibility to leverage on already deployed networks. In parallel to evolving HSPA, 3GPP is also specifying a new radio access technology, known as Long-Term Evolution (LTE). As described in Chapter 2, LTE targets more complex spectrum situations and has fewer restrictions on backwards compatibility. Thus, 3G evolution consists of two parallel tracks, both having their respective merits, for the radio access evolution. Figure 13.1 illustrates the relation between HSPA and LTE.
To support the new packet-data capabilities provided by the LTE radio interfaces, an evolved core network has been developed. The work on specifying the core network is commonly known as System Architecture Evolution (SAE).
Part IV of this book describes LTE and SAE, based on the specification work in 3GPP. The drivers behind LTE and SAE were explained in Chapter 2. Prior to starting the work on LTE and SAE, 3GPP agreed on a set of requirements, or design targets, to be taken as a basis for the development of LTE and SAE. Naturally, many of the SAE and LTE requirements overlap in terms of...
