WCDMA Network Architecture
The Wideband Code Division Multiple Access (WCDMA) network architecture:
WCDMA (Wideband Code Division Multiple Access) is a 3G cellular network technology that operates on a wideband frequency and offers high-speed data and voice services. The WCDMA network architecture is based on two main components: the Radio Access Network (RAN) and the Core Network (CN). Each plays a critical role in enabling communication between users and the broader telecommunication infrastructure.
WCDMA Radio Access Network (RAN)
The WCDMA RAN is primarily composed of two key elements: Node B and the Radio Network Controller (RNC). Node B is responsible for transmitting and receiving radio signals to and from the mobile devices (UE – User Equipment). The RNC, on the other hand, manages multiple Node Bs and controls the radio resources. It handles tasks such as power control, handovers, and scheduling for optimal resource utilization. It also manages the interface between the RAN and the Core Network.
WCDMA Core Network (CN)
The Core Network in WCDMA consists of several elements that facilitate the routing, processing, and delivery of calls and data. The key components include:
- Mobile Switching Center (MSC): Responsible for call setup, routing, and management of voice services. It interfaces with external networks like PSTN (Public Switched Telephone Network).
- Serving GPRS Support Node (SGSN): Manages packet-switched data, handling the delivery of data packets to and from mobile devices.
- Gateway GPRS Support Node (GGSN): Acts as a gateway between the mobile network and external IP-based networks, enabling internet and data connectivity.
- Home Location Register (HLR) and Visitor Location Register (VLR): Store subscriber information, including service details, location, and authentication data for mobility management.
WCDMA Interfaces
WCDMA also defines several key interfaces that enable communication between the RAN and CN. These include the Iu interface, which connects the RNC to the Core Network, and the Iub interface, which connects Node B to the RNC for efficient radio resource management and traffic handling. The Iu-CS interface is used for voice services, while the Iu-PS interface is used for data services.
WCDMA and QoS
WCDMA architecture provides mechanisms to ensure Quality of Service (QoS) for voice and data traffic. By implementing efficient resource management, WCDMA supports multiple services with varying requirements, ensuring that high-priority services like voice calls receive the necessary resources for smooth communication.
The WCDMA network architecture enables seamless communication between mobile devices and the core network. By separating the RAN and CN components, WCDMA allows for efficient management of voice and data services, along with optimized resource allocation. The use of various network elements such as Node B, RNC, MSC, SGSN, and GGSN ensures robust connectivity, efficient handovers, and high-speed data services across diverse user applications.
WCDMA including the RAN (Radio Access Network) and the CN (Core Network). The RAN is used to process all the radio-related functions, while the CN is used to process all voice calls and data connections within the UMTS system, and implements the function of external network switching and routing.
Logically, the CN is divided into the CS (Circuit Switched) Domain and the PS (Packet Switched) Domain. UTRAN, CN and UE (User Equipment) together constitute the whole UMTS system
A RNS is composed of one RNC and one or several Node Bs. The Iu interface is used between RNC and CN while the Iub interface is adopted between RNC and Node B. Within UTRAN, RNCs connect with one another through the Iur interface.
The Iur interface can connect RNCs via the direct physical connections among them or connect them through the transport network. RNC is used to allocate and control the radio resources of the connected or related Node B. However, Node B serves to convert the data flows between the Iub interface and the Uu interface, and at the same time, it also participates in part of radio resource management.