UMTS Architecture Diagram : Key Interfaces in Wireless Network
UMTS (Universal Mobile Telecommunications System) is a third-generation (3G) mobile cellular system designed to provide a wide range of services including voice, data, and multimedia at higher data rates than the previous 2G systems. The UMTS network architecture can be divided into three main components which include User Equipment (UE), UMTS Terrestrial Radio Access Network (UTRAN) and Core Network (CN).
Each component has specific functions and interfaces for communication. Let us break down UMTS architecture and its network interfaces as shown in the following diagram.
1. User Equipment (UE)
The UE is the mobile device used by the end-user. It communicates with the UTRAN via the Uu interface. User Equipments is composed of Mobile Equipment (ME) and USIM.
2. UMTS Terrestrial Radio Access Network (UTRAN)
The UTRAN handles the communication between the UE
and the Core Network. It consists of two main elements NodeB and RNC.
• NodeB (Base Station): Handles the physical layer of communication with the UE,
similar to the base station in GSM networks.
• Radio Network Controller (RNC): Manages radio resources and
controls the NodeBs. It handles tasks such as handovers, power control
and connection management.
3. Core Network (CN)
Core Network is composed of circuit switched and packet switched functional modules.
The Core Network manages the data and voice calls,
ensuring proper routing and connectivity. It consists of two main domains.
• Circuit-Switched (CS) Domain: Handles traditional voice calls.
For CS operations MSC and GMSC along with database modules such as VLR,
HLR will be available.
• Packet-Switched (PS) Domain: Handles data services like internet access.
For PS operations SGSN and GGSN will serve the purpose.
• GMSC will be connected with PSTN/ISDN in CS case.
GGSN is connected with Packet data Network (PDN) for PS case.
UMTS architecture interfaces
The architecture interfaces between system entities are summarized below.
➨Uu Interface: The air interface between the UE and the NodeB. This is where radio communication occurs,
including both voice and data transmission.
➨Iub Interface: Connects the NodeB and the RNC. It carries data from the UEs to the RNC and vice versa,
and it also transports signaling information for managing radio resources.
➨Iur Interface: Connects different RNCs within the UTRAN. This interface facilitates the coordination
and transfer of data and control information, especially during handovers when a UE moves
from the coverage area of one RNC to another.
➨Iu-CS Interface: Connects the RNC to the Circuit-Switched Core Network (CS-CN).
This interface is used for traditional voice call signaling and traffic. Iu-CS is interface between RNC and MSC.
➨Iu-PS Interface: Connects the RNC to the Packet-Switched Core Network (PS-CN).
This interface handles data services such as internet access and multimedia messaging.
Iu-PS is the UMTS network interface between RNC and SGSN.
Key benefits of UMTS Architecture in Wireless domain
The network architecture of UMTS system offers several key benefits in wireless communication,
contributing to its widespread adoption and success as a 3G technology.
Following are some of the primary advantages of this architecture.
1. UMTS supports higher data rates compared to 2G technologies like GSM. This enables faster internet access, video streaming, and other multimedia services.
2. The use of Wideband Code Division Multiple Access (W-CDMA) allows for more efficient use of the available spectrum, accommodating more users and higher data traffic.
3. UMTS supports global roaming, allowing users to access mobile services while traveling across different countries. The standardization and interoperability of UMTS networks make this possible.
4. UMTS provides improved voice quality through advanced codecs and error correction techniques, offering clearer calls compared to previous generations.
5. UMTS allows users to simultaneously access voice and data services, enabling activities like web browsing during a phone call.
6. The architecture supports various applications, from basic voice calls to complex multimedia and data services, catering to both consumer and business needs.
7. The RNC (Radio Network Controller) in UTRAN can dynamically allocate resources based on user demand, optimizing network efficiency and ensuring quality of service (QoS).
8. The architecture supports seamless handovers between cells and even between different network types (e.g., from UMTS to GSM, UMTS to LTE), maintaining continuous service as users move.
9. UMTS includes robust security mechanisms, such as strong encryption and mutual authentication,
protecting user data and privacy. Moreover, the architecture provides secure access to network services, reducing the risk of unauthorized use.
10. UMTS network is scalable and flexible to meet user demands and future upgrades.
Summary
In this UMTS architecture, the UTRAN handles radio communications and resource management, while the Core Network manages call setup, routing, and data services. The interfaces ensure seamless communication and handovers between different network elements and domains, providing users with continuous service.