Radio Access Network Architecture

This chapter gives a wide overview of the Universal Mobile Telephone System (UMTS) architecture, including an introduction to the logical network elements and the interfaces. The UMTS consists of logical network elements that each has a defined functionality. In the standards, network elements are defined at the logical level, but this quite often results in a similar physical implementation, especially since there are a number of open interfaces. The network elements are grouped into the Radio Access Network (RAN; UMTS Terrestrial RAN (UTRAN)) that handles all radio-related functionality, and the Core Network (CN), which is responsible for switching and routing calls and data connections to external networks. From a specification and standardization point of view, both UE and UTRAN consist of completely new protocols, the designs of which are based on the needs of the new WCDMA radio technology. On the contrary, the definition of CN is adopted from GSM. Controlled Vocabulary Terms 3G mobile communication; GSM; radio access networks