This chapter serves as a system level introduction to UMTS. We begin by describing the 3rd Generation Partnership Project, which is the organisation that defines the architecture and operation of the system. We continue by examining the architecture of UMTS, the interfaces between the different hardware components, and the protocol stacks that they use. At the end of the chapter are two shorter sections that describe the data flows within the system and the allocation of frequency spectrum to third generation systems. By the end of this chapter, you should have an appreciation of how the system fits together, and be ready to take on the details that are covered later in the book.

The 3rd Generation Partnership Project

Most of the information in this book originates in the specifications that define the architecture and operation of UMTS. These specifications are written by an organisation called the 3rd Generation Partnership Project (3GPP). In this section, we will describe how 3GPP is organised, and go on to discuss the specifications themselves.

Organisation of 3GPP

The 3rd Generation Partnership Project was formed in December 1998, to produce the technical specifications for UMTS. The formation of 3GPP came during the International Telecommunication Union's selection process for 3G telecommunication systems, and the first set of specifications was used as the member organisations' submission to the ITU. More recently, 3GPP has developed the UMTS specifications further and has expanded its role to handle the specifications for GSM, which had previously been produced by the European Telecommunications Standards Institute (ETSI).