Читать книгу Mobile Communications Systems Development - Rajib Taid - Страница 25

A Core Network (CN) domain is the backbone infrastructure for a mobile communications system and network which consists of hardware and systems. A CN is also a gateway to the traditional PSTN system. CN primarily takes care of all the call control‐related functions. A CN also performs various functions such as the authentication, charging, and setup of end‐to‐end connections required for different telecommunication services. A CN is independent of the radio connection technology for a mobile device. In the case of the LTE system, both the core network and the RAN are fully based on IP PS due to which it is also called the Evolved Packet System (EPS). In the case of the 5G system also, both the core network and the RAN are fully based on the IP PS network.

From Figures 2.1–2.3, one can see that the GSM/GPRS and the UMTS differ in the AN only. However, UMTS reuses the core network elements (e.g. MSC, SGSN, GGSN, and so on) from the GSM core network. In the case of the LTE system, the entire architecture is, however, different from the GSM and UMTS system. Neither has it reused the AN nor has it reused the CN elements from the previous cellular systems. The CN of an LTE network works on top of an IP transport network, whereas the GSM and UMTS CN may use mixed transport networks.