Читать книгу Mobile Communications Systems Development - Rajib Taid - Страница 19

Similarly, consider Figure 2.3 for the different network elements found in a Universal Mobile Telecommunications System (UMTS) or 3G network. A UMTS network contains network elements such as the UE (known as the MS in GSM network), NodeB (similar to a GSM BTS), Radio Network Controller‐RNC (similar to a GSM BSC), SGSN, GGSN, Gateway Mobile Switching Center (GMSC), and MSC. These network elements together provide both the CS and PS data services to subscribers as illustrated in Figure 2.3.

Similar to a GSM network, the RNC together with the NodeB is called the Radio Network Subsystem (RNS) in a UMTS network. RNS transmits and receives information with UEs through radio frequency communications. The flow of CS voice call and PS data call is being shown with a bold solid line in the diagram Figure 2.3. The SGSN, GGSN, GMSC, and MSC network elements are reused from the GSM network. Figure 2.3 is the first version of the UMTS network architecture, also referred to as the Release 99. The UMTS CN elements are adapted from the Pre‐Release 99 GSM and GPRS networks. Subsequent releases of the UMTS network are known as the Release 4, Release 5, and so on, which are described later in Section 2.3.2.

Figure 2.3 Network architecture and elements of a UMTS network.