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INTRODUCTION TO GSM/WCDMA CORE NETWORK : lesson - 1 The major parts of a modern mobile network are the Radio Access Network (RAN) and the Core Network (CN). The GSM and WCDMA access part are designed to provide accesses to mobile User Equipment (UE) and handle the service classes Background, Interactive, Streaming and Conversational in WCDMA. The Core Network contains a range of nodes to support circuit or packet switched services belonging to the service classes above. Ericssons Core Network is common for GSM, General Packet Radio Service (GPRS), Enhanced Data Rates for a Global Evolution (EDGE) and WCDMA network solutions and is called GSM/WCDMA Core Network. The GSM/WCDMA Core Network contains functionality realizing the features below in accordance to the released standards:Call Control. The CN handles the setup, maintenance and release of Voice, Packet, Short Message Service (SMS) and Multimedia calls.

Mobility Management

Charging

Subscriber data management

Service Control

Security

Through connections in the backbone network. The payload processing is performed in the Media Gateway (MGW) but triggered by the CN.

The CN also controls the interfaces towards access networks for GSM- Base Station System (BSS), WCDMA RAN and external networks.

GSM/WCDMA CORE NETWORK DOMAINSThe GSM/WCDMA Network is logically divided into domains related to the type of the offered service. These are:Telephony (Circuit Switched, CS) domain. The telephony domain of the Core Network includes the major node products: Mobile Switching Centre MSC, Transit Switching Center (TSC), Signaling Transfer Point (STP), and MGW. These nodes can be combined to provide complete mobile switching networks, GSM and/or WCDMA, in traditional non-layered network architecture and/or layered architecture where control and user plane are separated onto different nodes.

Packet Switched (PS) domain. The nodes in the packet domain provide GPRS packet functionality for entry level to large-scale packet data networks for both GSM and WCDMA. The PS nodes are the Serving GPRS Support Node, SGSN and Gateway GPRS Support Node, GGSN.

Transport domain. It provides transport services to voice and packet data calls. In the transport domain Internet Access Server (IAS) provides an efficient solution for connecting GSM circuit data to a packet network. Mobile- Packet Backbone Network, (M-PBN), provides a cost efficient solution for packet backbone implementations.

Support Domain. Main function in current release is the Lawful Interception. When an operator builds a Public Land Mobile Network (PLMN), the legal authorities in that country may want to listen to the traffic that is transmitted through the network. This tapping performed by the authorities is called lawful interception. Lawful interception enables the authorities to trace any kind of traffic (speech, data, signaling information, short messages etc.) in case of investigation of expected criminal activity of the target subscriber(s). In some countries the possibility to perform lawful interception is a legal pre-requirement to launch and operate a commercial PLMN.