UMTS - WCDMA Tutorial

UMTS - WCDMA tutorial presentation.



WCDMA RADIO ACCESS NETWORK
WCDMA RAN is a radio access network that provides a connection between the User Equipment (UE) and the Core Network (CN). The networks are separate and communicate with each other via Iu interface. The WCDMA RAN and CN are maintained from Operations Service System - Radio& Core (OSS-RC). It communicates via Mu interface. The following subsec-tions describe the parts where a Radio Access Network (RAN) consists of.

Radio Access Network
Radio access network is a network providing interface for mobile terminals or mobile phones to access 3G networks. This interface is called Uu. The Radio access network consists of three network elements: Radio Base Sta-tions (RBS), Radio Network Controllers (RNCs) and ATM-switch which is called RXI. Radio Access Bearers (RABs) are used to provide services be-tween the core network (CN) and mobile terminals. All the RAN nodes are based on the same platform which is called Cello Packet Platform (CPP).

Radio Base Station
Radio Base Station (RBS) provides radio resources for mobile terminals. It has radio equipment such as transceivers and antennas, which are needed to serve cells in the network. Radio Base Station works between the user Equipment (UE) and the Radio Network Controller (RNC), serving radio transmission over the air interface. The main functions of the Radio Base Station are power control, channel coding, spreading and scrambling and modulation.

Radio Network Controller
The Radio Network Controller (RNC) handles Radio Access Bearers (RABs) for the radio network and user data. RNC is connected to the core network with Iu interface. RNC provides a control message bearer service between mobile terminals and the core network. It also controls call handovers within the Radio Access Network (RAN). The Iur interface is used to communicate from RNC to other RNC. The Iub interface is used to communicate from RBS to RNC.

ATM-Switch RXI
RXI handles the switching between RNC and RBS. RXI enables multiple RBS connected to the RNC. It is controlled by OSS-RC via Mut interface.

Operations and Support System- Radio & Core (OSS-RC)
Operations Service System - Radio & Core (OSS-RC) is a system that provides the performance management, network monitoring and network statistics from the RAN. RAN is controlled by the OSS-RC. It collects information and counter data from the RNC, RXI and RBS and that information can be analyzed by MoShell which is Ericsson’s internal system tool or by Operation and Support System Graphical User Interface (OSS GUI) that customer use to manage Network Elements (NEs). OSS-RC is a customer tool which operators use for alarm handling, cellular network administration and for mobile subscribers. OSS-RC contains appli-cations for performance management, configuration and supervision in RAN.

here is the Architecture of UMTS :
The UMTS Architecture pdf