From GSM to LTE-Advanced Pro and 5G, 4th Edition

3Universal Mobile Telecommunications System (UMTS) and High‐Speed Packet Access (HSPA)

The Universal Mobile Telecommunications System (UMTS) is a third‐generation wireless telecommunication system and followed in the footsteps of the Global System for Mobile Communications (GSM) and General Packet Radio Service (GPRS). Since GSM was standardized in the 1980s, huge progress had been made in many areas of telecommunications. This allowed system designers at the end of the 1990s to design a new system that went far beyond the capabilities of GSM and GPRS. UMTS combines the properties of the circuit‐switched voice network with the properties of the packet‐switched data network and offers a multitude of new possibilities compared to the earlier systems. UMTS was not defined from scratch and reuses a lot of GSM and GPRS. Therefore, this chapter first gives an overview of the advantages and enhancements of UMTS compared to its predecessors, which have been described in the previous chapters. After an end‐to‐end system overview, the focus of the chapter moves to the functionality of the UMTS radio access network. New concepts like the Radio Resource Control (RRC) mechanisms as well as changes in mobility, call control, and session management are also described in detail.

Before UMTS was succeeded by 4th and 5th generation mobile systems, the UMTS radio network system was significantly enhanced over the years to offer broadband speeds far beyond the original design. These high‐speed ...