Mobile Networks Architecture

Chapter 3

The UMTS Network

In this chapter, section 3.1 explains the services provided by the UMTS (Universal Mobile Telecommunications System) network, the main ones being the telephone service and the data transmission service. These services are implemented in CS (Circuit Service) or PS (Packet Service) mode, solely for data transmission.

Section 3.2 explains the architecture of the UMTS network, which consists of two sub-systems. As for the GSM (Global System for Mobile) and GPRS (General Packet Radio Service) networks, the core network includes the Network Sub-Systems (NSS) and GPRS Sub-Systems (GSS). The access network UTRAN (UMTS TRAnsport Network) provides a new technique for the allocation of a radio source to a flow.

Section 3.3 explains the radio interface between the mobile and the UMTS network. The description of the transmission chain essentially concerns the data link protocols, multiplexing by physical channel codes, modulation and frequency plan.

Section 3.4 describes the procedures limited to the UTRAN. Such procedures concern resource establishment for signaling or traffic, the implementation of the soft handover, the relocation of the anchor point and the inter-system handover.

Section 3.5 explains the HSPA (High Speed Packet Access) evolutions, which consist of an increase in rate via a new type of modulation, the concatenation of several physical channels and the exploitation of several propagation paths.

3.1. The services

The UMTS network offers a range of ...