UMTS – Universal Mobile Telecommunications System is another name for the mobile 3G network. Find out about this 3G technology and how it works.



UMTS Overview

UMTS uses different technologies for enabling the mobile users to enjoy the benefits of this fascinating system.

  • User Equipment
  • Radio Access Network – UTRAN
  • Core Network

User Equipment

Used equipment are devices on the customer premises. They are also often called mobile terminals. With their radio connection to the mobile operator network they enable different services. Available services in the UMTS networks are:

  • Voice calls
  • Text messages or SMS messages
  • Mobile broadband internet access
  • MMS messages.

Also, there are different kinds of mobile terminals used in the 3G mobile networks:

    • Mobile phones or cellular phones
    • Tablets
    • Dongles
    • M2M or Machine to Machine devices
    • MiFi – Mobile WiFi hot spot

Radio Access Network – UTRAN

UTRAN – UMTS Terrestrial Radio Access Network is part of the mobile operator network between the user equipment and core network. It enables radio access connectivity to the user equipment.

General name for it is RAN or Radio Access Network. In 3G networks or UMTS it is called UTRAN. In 2G networks the RAN is called GERAN or GSM/Edge Radio Access Network.

UTRAN is based on the WCDMA (Wideband Code Division Multiple Access) standard and, unlike 4G, it has two tiers:

  • NodeB – Base Transceiver Station
  • RNC – Radio Network Controller

Find out about how exactly radio access network in UMTS is working in the post WCDMA – 3G Network or UMTS Mobile Broadband Access.


Base Transceiver Station (BTS) in UMTS networks is called NodeBs. NodeBs communicate directly with the mobile terminals with their radio frequency receivers and transmitters. Mobile terminals can’t communicate directly between each other. In the 3G mobile network, mobile terminals communicate between themselves over NodeB.

RNC – Radio Network Controller

The RNC or Radio Network Controller is responsible for control of the NodeBs. RNC handles radio resource management and mobility management.

Core Network

Core network consist of the two basic parts:

  • Circuit Switched (CS)
  • Packet Switched (PS)

Circuit Switched (CS) Core Network

Circuit Switched core network is responsible for voice calls. It consists of the following parts:

  • MSC
  • MGW
  • HLR

Mobile Switching Center (MSC)

Mobile Switching Center (MSC) is the node responsible for routing voice calls and SMS messages or text messages.

Media Gateway (MGW)

Media Gateway (MGW) is translation device or gateway between PLMN public land mobile network and core network of the mobile network. Its main function is to convert between different transmission and coding techniques.

More about the circuit switch core network  and Ericsson solution for the UMTS technology read in Mobile Switching.

Home Location Register (HLR)

Home Location Register (HLR) is the main database in mobile networks. It contains information about each subscriber in the mobile network. HLR needs to store details about the every SIM card that mobile operator issues.

Packet Switched (PS) Core Network

Packet Switched (PC) Core Network is responsible for the mobile broadband internet access. It consists of two basic parts:

  • SGSN
  • GGSN

Serving GPRS Support Node (SGSN)

Serving GPRS Support Node (SGSN) connects the RAN network (UTRAN in 3G) and core network. SGSN performs the following:

  • Packet routing and transfer
  • Mobility management
  • Authentication
  • Charging

The connection between UTRAN and packet switched core network is the RNC – SGSN interface. The main purpose of SGSN in the UMTS network is mobility management of mobile terminals, together with the RNC.

Gateway GPRS support node (GGSN)

Gateway GPRS support node (GGSN) is the node in the UMTS core network that connects the 3G mobile network with the internet. The GGSN performs the following functions:

  • IP pool management
  • IP address allocation
  • Routing
  • QoS – Quality of Service
  • Subscriber screening

GGSN is a router and forwards packets between SGSN (mobile terminals connected to the SGSN via NodeB and RNC) and external network (internet).

HSPA and HSDPA are the latest versions of the UMTS and WCDMA. Read more about this topic in the article HSDPA and HSPA – The Fastest 3G Technology.

UMTS Network Topology

In the video clip below you can check the facts about the 3G mobile network.

UMTS – Conclusion

UMTS or 3G mobile network has made great impact not only on the telecom industry, but on all modern society. Social networking, smartphones, and exponential growth of mobile subscribers – all these phenomena are caused by the 3G mobile network.

But as you know UMTS and 3G is not the latest trend in the mobile industry. 4G and LTE are the next step in the evolution of the mobile wireless technology. More about the 4G and LTE read in the post What is 4G LTE, What does 4G LTE mean? What is LTE network.

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