UMTS facts for kids

Kids Encyclopedia Facts

The Universal Mobile Telecommunications System (UMTS) is a way that mobile phones and other devices connect to the internet and make calls. It's a type of 3G mobile network, which means it's the "third generation" of mobile technology. UMTS is built on the same ideas as the older GSM networks.

This system was created and is looked after by a group called 3GPP. UMTS is part of a bigger set of standards for mobile communication called IMT-2000. It uses a special radio technology called W-CDMA (Wideband Code-Division Multiple Access). This technology helps mobile networks send more data faster.

UMTS is a complete network system. It includes the parts that send radio signals (called UTRAN) and the main "brain" of the network (called the core network). It also uses SIM cards to identify users. Sometimes, UMTS is also known as FOMA or 3GSM. Unlike some other mobile technologies like EDGE, UMTS usually needs new base stations and special radio frequencies to work.

What UMTS Can Do

UMTS networks can send data very quickly. The fastest speeds can reach up to 42 Mbit/s when the network uses a newer version called HSPA+. For regular users, older UMTS phones (from Release '99) could get speeds up to 384 kbit/s. Newer phones with HSDPA can reach 7.2 Mbit/s when downloading. These speeds are much faster than older mobile networks like GSM.

Since 2006, many UMTS networks have been updated with HSDPA, which is sometimes called 3.5G. This allows download speeds of up to 21 Mbit/s. Work is also being done to make uploads faster with HSUPA. The next big step after UMTS is LTE, which is a 4G standard. LTE offers even faster speeds, starting at 100 Mbit/s for downloads.

When UMTS networks first started around 2002, they focused on things like mobile TV and video calls. However, people mostly use the fast speeds of UMTS for Internet access now. Users found they didn't really want video calls. Instead, they preferred fast access to the internet on their phones or by connecting their phones to computers using Wi-Fi, Bluetooth, or USB.

How UMTS Connects Devices

How a UMTS network is set up

Another view of UMTS network parts

UMTS uses different ways to send signals through the air. These are called air interfaces. It also uses the main network part from GSM and the same voice coding methods.

The main air interfaces are part of something called UMTS Terrestrial Radio Access (UTRA). The most common one for mobile phones is called W-CDMA. This is also known as the "Uu interface," which connects your phone to the UMTS radio network.

It's important to know that names like W-CDMA, TD-CDMA, and TD-SCDMA sound like they only describe how signals are shared. But they actually refer to the entire way the radio connection works.

W-CDMA (UTRA-FDD)

The 3G symbol on an Android phone

A UMTS base station on a building roof

W-CDMA is a standard for 3G mobile networks. It lets you make calls, send texts, and use MMS. It can also send data at high speeds. This allows mobile companies to offer faster internet and streaming services.

W-CDMA uses two 5 MHz wide channels to send and receive information. This is different from the competing CDMA2000 system, which uses smaller 1.25 MHz channels. Some people criticized W-CDMA for needing a lot of radio space. This sometimes made it slower to set up in countries that were slow to give out new frequencies for 3G.

The original frequencies for UMTS were around 1885–2025 MHz for sending data from your phone (uplink) and 2110–2200 MHz for receiving data (downlink). In the US, different frequencies are used because the 1900 MHz band was already taken. While UMTS on 2100 MHz is common, some countries also use 850 MHz, 900 MHz, or 1900 MHz.

W-CDMA is the basis for Japan's NTT DoCoMo's FOMA service. It's the most widely used part of the UMTS family. It helps achieve faster speeds and support more users compared to older methods.

Even though W-CDMA is a new radio technology, it uses the same main network as older 2G GSM networks. This means phones can switch between 2G and 3G easily.

How W-CDMA Was Developed

In the late 1990s, NTT DoCoMo in Japan created W-CDMA for their 3G network, FOMA. They then shared its design with the International Telecommunication Union (ITU). The ITU accepted W-CDMA as one of the international 3G standards. Later, W-CDMA was chosen as the main radio technology for UMTS.

A company called Qualcomm was very important in developing earlier CDMA phone networks. They created a system called CDMA2000 3x to try and combine W-CDMA and CDMA2000. However, W-CDMA became the most popular technology worldwide. By April 2012, there were 457 W-CDMA networks in 178 countries. Some CDMA2000 operators even switched to W-CDMA to allow for easier international roaming and upgrades to LTE.

Even though W-CDMA was new and expensive to set up, it became the leading standard.

Why W-CDMA Was Chosen

W-CDMA uses two 5 MHz radio channels. This is different from CDMA2000, which uses smaller 1.25 MHz channels. W-CDMA is not just a wider version of CDMA2000; they are different in many ways. From an engineering point of view, W-CDMA offers a different balance of cost, capacity, and performance. It was also thought to be better for very crowded cities in Europe and Asia.

W-CDMA has a full set of rules that explain how a mobile phone talks to the network tower. These rules cover how signals are sent and how data is organized.

Where W-CDMA Is Used

The world's first commercial W-CDMA service, FOMA, started in Japan in 2001 by NTT DoCoMo. In other places, W-CDMA networks are usually known as UMTS.

W-CDMA has even been used in satellite communications for the U.S. Mobile User Objective System. This system uses satellites instead of cell towers.

Many countries have either sold off radio frequencies to companies or asked them to show their plans for using the licenses. This process has sometimes made it very expensive for mobile companies. Most companies have a deadline to set up their service in a certain area, or they might lose their license.

Vodafone launched UMTS networks in Europe in February 2004. Other companies like MobileOne in Singapore, AT&T Mobility in the US, and Rogers in Canada also launched W-CDMA services.

In South Korea, SK Telecom and KTF started offering W-CDMA in December 2003. In Norway, Telenor and NetCom introduced W-CDMA by the end of 2004. Maxis Communications and Celcom in Malaysia started offering services in 2005.

UTRA-TDD

UMTS-TDD is another version of UMTS networks. TDD stands for time-division duplexing. This means that the sending and receiving of data share the same radio frequency, but at different times. UMTS-TDD is mostly used for providing internet access, similar to how WiMAX works.

UMTS-TDD is not directly compatible with the more common UMTS-FDD (W-CDMA). Devices made for one standard usually won't work on the other unless they are specifically designed to. This is because they use different radio technologies and frequencies.

The two main UMTS air interfaces for UMTS-TDD are TD-CDMA and TD-SCDMA. Both use a mix of code-division multiple access (CDMA) and time-division multiple access (TDMA). This means the frequency is divided into time slots, and then those time slots are further divided using special codes.

TD-CDMA (UTRA-TDD High Chip Rate)

TD-CDMA uses spread-spectrum technology across many time slots. It is part of the UMTS-TDD system that uses 5 MHz chunks of radio space. Each chunk is divided into 10-millisecond frames, which contain fifteen time slots. These time slots are set up for either sending or receiving data. Unlike W-CDMA, TD-CDMA doesn't need separate frequency bands for sending and receiving. This allows it to be used in smaller frequency areas.

TD-CDMA is part of the IMT-2000 standards. It is closely related to W-CDMA and offers similar types of channels. The faster HSDPA/HSUPA features of UMTS are also used with TD-CDMA.

In the United States, this technology has been used for public safety in New York City.

TD-SCDMA (UTRA-TDD Low Chip Rate)

TD-SCDMA (Time-Division Synchronous Code-Division Multiple Access) is another radio interface found in UMTS networks. It was developed in China as an alternative to W-CDMA.

TD-SCDMA uses TDMA combined with a special synchronous CDMA system on 1.6 MHz slices of radio space. This allows it to be used in even tighter frequency bands than TD-CDMA. China developed this standard to reduce the need to pay fees to companies that own patents on other 3G technologies. TD-SCDMA was added to the UMTS rules later, in Release 4.

Like TD-CDMA, TD-SCDMA is known as IMT CDMA TDD within the IMT-2000 standards. However, TD-SCDMA networks are not compatible with W-CDMA or TD-CDMA networks.

Why TD-SCDMA Was Created

TD-SCDMA was developed in China by groups like the Chinese Academy of Telecommunications Technology (CATT) and Datang Telecom. The main goal was to avoid relying on Western technology and paying patent fees.

Supporters of TD-SCDMA also say it works better in crowded areas. It is also meant to cover all kinds of uses, while W-CDMA is best for balanced data traffic and large cell areas.

China planned to launch a national TD-SCDMA network by 2005, but it took longer. Large-scale tests with 60,000 users in eight cities happened in 2008. On January 7, 2009, China Mobile was given a license to use TD-SCDMA. By August 2009, China Mobile had over 1.3 million TD-SCDMA users.

TD-SCDMA is not widely used outside of China.

How TD-SCDMA Works

TD-SCDMA uses TDD, which means it shares the same frequency for sending and receiving data. It can change how much time is used for sending or receiving, which is good for internet traffic where you might download a lot more than you upload. Since it doesn't need separate frequencies, it's more flexible with how radio space is used. Using the same frequency for both directions also helps the base station understand the signal better.

TD-SCDMA also uses TDMA in addition to CDMA. This reduces the number of users in each time slot, making it simpler to manage. However, it can also reduce how far the signal reaches and how well it works when you're moving.

The "S" in TD-SCDMA means "synchronous." This means that signals from phones are kept in sync at the base station. This helps reduce interference between users and increases the network's capacity.

History of TD-SCDMA

On January 20, 2006, China officially announced TD-SCDMA as its 3G mobile standard. Trials took place from March to October 2006, but the results weren't perfect. In early 2007, the Chinese government told China Mobile to build trial networks in eight cities.

On March 28, 2008, China Mobile started "commercial trials" for 60,000 test users. Other 3G networks in China were delayed until TD-SCDMA was ready.

In January 2009, China's Ministry of Industry and Information Technology (MIIT) gave licenses for three different 3G standards to three different carriers. China Mobile received the TD-SCDMA license. This was to make sure the new system had the support it needed.

However, this split caused problems for China Mobile. Users and engineers found there weren't enough suitable phones for the network. Building base stations was also slow. The network connection was often slower than the other two carriers, causing China Mobile to lose market share. By 2011, China Mobile started focusing on TD-LTE, and TD-SCDMA stations began to close in 2016.

Where TD-SCDMA Is Used

Here's a list of mobile networks using TD-SCDMA:

Operator	Country	Frequency (MHz)	Band	Launch date	Notes
China Mobile	China	2100	A+ (Band 34)	Jan 2009	(↓↑) 2010–2025 MHz Network being phased out in favour of LTE.
China Mobile	China	1900	A- (Band 33)	Jan 2009	(↓↑) 1900–1920 MHz (Subset of Band 39) Previously used by Xiaolingtong (PHS). Network being phased out in favour of LTE.
none	China	1900	F (Band 39)	N/A	(↓↑) 1880–1920 MHz No deployments, later used for TD-LTE instead.
none	China	2300	E (Band 40)	N/A	(↓↑) 2300–2400 MHz No deployments, later used for TD-LTE instead.
Xinwei (CooTel)	Nicaragua	1800	N/A	Apr 2016	(↓↑) 1785–1805 MHz

How UMTS-TDD Compares to UMTS-FDD

Regular UMTS, known as UMTS-FDD, uses W-CDMA and sends and receives data on different frequencies. UMTS-TDD, however, shares the same frequency for both sending and receiving. This allows network operators to be more flexible with how they use the available radio space. For example, if many people are downloading videos, the network can give more time to downloads.

UMTS-TDD is often used for mobile internet services rather than regular phone calls. This is because TDD is usually not allowed on the frequencies used for standard mobile phone services. TDD technologies help use leftover radio space that isn't paired up.

In Europe, certain frequency bands are set aside for UMTS-TDD or similar technologies. These include 1900 MHz, 1920 MHz, and 2010–2025 MHz. Some countries also use the 2500–2690 MHz band.

Where UMTS-TDD Is Used

UMTS-TDD has been set up for public or private networks in at least 19 countries. These include Australia, Czech Republic, France, Germany, Japan, New Zealand, Botswana, South Africa, the UK, and the USA.

In the US, its use has been limited. It's been chosen for a public safety network in New York. However, other standards like WiMAX have become more popular for general mobile internet access.

Other Competing Technologies

There are other systems that provide fast internet access, such as WiMAX and HIPERMAN. UMTS-TDD has the advantage of being able to use an operator's existing UMTS/GSM network if they have one. It also includes modes for regular phone calls. However, UMTS-TDD operators sometimes face rules that prevent them from offering all UMTS services. For example, in the UK, UMTS-TDD frequencies can't be used for phone service yet.

WiMAX and HIPERMAN can offer much faster speeds when your mobile device is very close to the network tower.

Many users might find their internet needs met by Wi-Fi hotspots in places like restaurants. They might also use the internet provided by their mobile phone company. UMTS-TDD (and systems like WiMAX) offer more consistent mobile access and are generally faster than what a regular mobile phone might offer.

Radio Access Network

UMTS also defines the Universal Terrestrial Radio Access Network (UTRAN). This network is made up of many base stations. These base stations might use different radio standards and frequency bands.

UMTS and GSM/EDGE can share the same main network (Core Network). This means UTRAN can be used instead of GERAN (GSM/EDGE RAN). This allows phones to switch smoothly between 2G and 3G networks depending on coverage. Because of this, UMTS and GSM/EDGE radio networks are sometimes called UTRAN/GERAN together.

UMTS networks are often combined with GSM/EDGE, which is also part of the IMT-2000 standards.

The part of the network that talks to your phone (User Equipment or UE) uses several important rules called protocols. These include RRC, PDCP, RLC, and MAC. The RRC protocol handles things like setting up connections, measuring signals, and managing security. The RLC protocol helps send data reliably. MAC handles scheduling data over the air.

A "Radio Bearer" (RB) describes how data is sent. It sets the maximum amount of data that can be sent in a certain time. Signaling messages, which control the network, are sent on special Signaling Radio Bearers (SRBs). Your actual data, like calls or internet traffic, goes on data RBs.

Security in UMTS involves two main steps: integrity and ciphering. Integrity checks that messages haven't been changed and come from the right source. Ciphering makes sure that no one can listen in on your data over the air. Both are used for control messages, but only ciphering is used for your actual data.

Core Network

UMTS uses the same main network standard as GSM/EDGE. This makes it easier for existing GSM companies to switch to UMTS. However, upgrading to UMTS can still be expensive. While much of the main network can be reused, getting new frequency licenses and adding UMTS equipment to existing towers costs a lot.

The main network can connect to other large networks, like the Internet or a phone network. UMTS includes the lowest three layers of the OSI model. The network layer manages how data is sent between your phone and the main network, including when your phone moves from one area to another.

Frequencies and Channels

UARFCN

A UARFCN (which stands for UTRA Absolute Radio Frequency Channel Number) is used to identify a specific frequency in the UMTS frequency bands.

Usually, you can figure out the channel number from the frequency in MHz by multiplying the frequency by 5. But for some channels, especially in North America, special numbers are used.

How Spectrum Is Used

Over 130 licenses for UMTS have been given out worldwide. In Europe, the process of selling these licenses happened when technology companies were very popular. Some countries sold licenses for very high prices, especially in the UK and Germany. In Germany, companies paid a total of €50.8 billion for six licenses. These high costs put some European phone companies close to going bankrupt.

Over the last few years, some companies have written off these high license costs. Between 2007 and 2009, all three Finnish mobile companies started using 900 MHz UMTS. They shared this with their 2G GSM base stations to cover rural areas. This trend is expected to grow in Europe.

The 2100 MHz band, which is used for UMTS in Europe and most of Asia, is already in use in North America. The 1900 MHz range is used for 2G services, and the 2100 MHz range is used for satellites. However, regulators have made some of the 2100 MHz range available for 3G services, along with a different range around 1700 MHz for uploads.

AT&T Wireless started UMTS services in the United States by the end of 2004 using the existing 1900 MHz spectrum. After Cingular bought AT&T Wireless, they launched UMTS in some US cities. Cingular then became AT&T Mobility and added UMTS networks at 850 MHz to improve their existing 1900 MHz network. They now offer phones that work on both 850/1900 MHz UMTS bands.

T-Mobile in the US first focused on the 1700 MHz band for UMTS. But T-Mobile has been moving users from 1700 MHz to 1900 MHz to use the 1700 MHz spectrum for 4G LTE services.

In Canada, UMTS is available on the 850 MHz and 1900 MHz bands through Rogers and the Bell-Telus networks. Newer providers like Wind Mobile, Mobilicity, and Videotron use the 1700 MHz band.

In 2008, the Australian company Telstra replaced its old CDMA network with a national UMTS-based 3G network called NextG, operating on the 850 MHz band. Telstra also uses the 2100 MHz UMTS network. Optus is setting up a 3G network on the 2100 MHz band in cities and the 900 MHz band in rural areas. Vodafone is also building a 3G network using the 900 MHz band.

In India, BSNL started its 3G services in October 2009, beginning in larger cities. The 850 MHz and 900 MHz bands provide better coverage over longer distances compared to 1700/1900/2100 MHz networks. This makes them good for rural areas.

Mobile companies in South America are also starting to use 850 MHz networks.

Global Roaming and Compatibility

UMTS phones and data cards are very easy to use when traveling. They are designed to work on other UMTS networks if the phone companies have agreements. Also, most UMTS phones can also use GSM networks. So, if you lose UMTS coverage during a call, it can smoothly switch to GSM. However, roaming charges are usually much higher than your normal usage fees.

Most UMTS companies believe that being able to use your phone anywhere in the world is very important. To make this possible, UMTS phones usually support several different frequencies in addition to GSM. Different countries use different UMTS frequencies. Europe first used 2100 MHz, while most US carriers use 850 MHz and 1900 MHz. T-Mobile in the US uses 1700 MHz (upload) / 2100 MHz (download). These bands are also used in Canada and Latin America. A UMTS phone and network must use a common frequency to work together. Because of these different frequencies, early UMTS phones made for the US might not work elsewhere, and vice versa. There are now 11 different frequency combinations used globally, including frequencies that used to be only for 2G services.

UMTS phones use a USIM card (like GSM's SIM card). They can also work with GSM SIM cards. This is a worldwide standard for identification. It allows a network to identify and check the USIM in your phone. Roaming agreements let calls be sent to you when you're traveling and determine what services and prices are available. Besides your information, the USIM stores phone contacts. You can move a USIM to another UMTS or GSM phone, and the phone will use your details from the card. This means the USIM, not the phone, determines your phone number and how calls are billed.

Japan was the first country to use 3G. Since they didn't use GSM before, their 3G phones were smaller. In 2002, NTT DoCoMo's FOMA 3G network was the first commercial UMTS network. It used an early version of the standard, so it wasn't fully compatible with UMTS at the radio level. However, it used standard USIM cards, so you could roam by moving your USIM card to a UMTS or GSM phone when traveling. Now, both NTT DoCoMo and SoftBank Mobile use standard UMTS.

Phones and Modems

The Nokia 6650, an early (2003) UMTS phone

All major phone makers now produce 3G phones. Early 3G phones and modems were made for specific frequencies in their country. This meant they could only roam to other countries using the same 3G frequency. However, they could switch back to the older GSM standard. Canada and the USA share common frequencies, as do most European countries.

You can use a cellular router, PCMCIA card, or USB card to get 3G internet services on your computer. Some of these devices even install their own software, so you don't need to know much about technology to get online quickly. If your phone supports 3G and Bluetooth 2.0, you can connect several Bluetooth-enabled laptops to the internet. Some smartphones can also act as a mobile Wi-Fi hotspot.

Very few 3G phones or modems support all 3G frequencies (850/900/1700/1900/2100 MHz). In 2010, Nokia released phones like the N8 and E7 that could use five different 3G bands. Many other phones offer more than one band, which still allows for a lot of roaming. For example, Apple's iPhone 4 has a chip that works on 850/900/1900/2100 MHz. This lets it be used in most countries where UMTS-FDD is available.

Other Competing Standards

The main competitor to UMTS is CDMA2000. Unlike UMTS, CDMA2000 is an upgrade to an existing 2G standard, cdmaOne. It can work within the same frequency areas. This, along with CDMA2000's smaller bandwidth needs, makes it easier to set up in existing radio spaces. In some cases, GSM operators only have enough radio space for either UMTS or GSM, not both. Where CDMA2000 is used, it often exists alongside UMTS.

Another competitor is EDGE. This is an upgrade to the 2G GSM system that uses existing GSM frequencies. It's much easier and cheaper for phone companies to add EDGE by upgrading their current GSM equipment. However, EDGE is developed by the same group as UMTS (3GPP), so it's not a true competitor. Instead, it's used as a temporary solution before UMTS is fully rolled out, or as a way to cover rural areas. This is easy because GSM/EDGE and UMTS share the same main network.

China's TD-SCDMA standard is also sometimes seen as a competitor. TD-SCDMA was added to UMTS's Release 4. Unlike TD-CDMA, which works with W-CDMA, TD-SCDMA is good for both small and large cell areas. However, not many companies support it, which stops it from being a big competitor.

While DECT can technically compete with UMTS in crowded city areas, it's mostly used for cordless phones at home and private networks inside buildings.

All these competing technologies have been accepted by the ITU as part of the IMT-2000 family of 3G standards, along with UMTS-FDD. For internet access, other competing systems include WiMAX and Flash-OFDM.

Upgrading from GSM/GPRS to UMTS

When a phone company upgrades from a GSM/GPRS network to UMTS, some parts of the network can be reused:

Home Location Register (HLR)
Visitor Location Register (VLR)
Equipment Identity Register (EIR)
Mobile Switching Center (MSC)
Gateway Mobile Switching Center (GMSC)
Authentication Center (AUC)
Serving GPRS Support Node (SGSN)
Gateway GPRS Support Node (GGSN)

However, some parts of the GSM/GPRS radio network cannot be reused for UMTS:

Base transceiver station (BTS)
Base station controller (BSC)
Packet Control Unit (PCU)

These old parts can stay in the network. This allows both 2G and 3G networks to work at the same time while the upgrade happens and new 3G phones become available.

The UMTS network adds new parts:

Node B (which is like a base transceiver station)
Radio Network Controller (RNC)
Media Gateway (MGW)

The job of the MSC changes with UMTS. In GSM, the MSC handled all call connections. In UMTS, the Media Gateway (MGW) takes care of data transfer for calls, and the MSC controls the MGW.

Challenges and Issues

Some countries, like the United States, have given out radio frequencies differently from what the ITU suggested. This means the common UMTS bands (UMTS-2100) weren't available. In these countries, different bands are used. This stops existing UMTS-2100 equipment from working there and means different equipment has to be made. However, UMTS phones are getting better at working on many different bands. Many UMTS phones now work on multiple UMTS and GSM bands. Phones that work on five different 3G bands (850, 900, 1700, 2100, and 1900 MHz) are becoming more common.

In its early days, UMTS had some problems. Phones were heavy and their batteries didn't last long. For example, the Motorola A830, an early UMTS phone, weighed over 200 grams. Another big issue was dropped calls, especially when switching from UMTS to GSM. Customers found their calls would drop because the phone could only switch from UMTS to GSM, not back. In most networks today, this is no longer a problem.

Compared to GSM, UMTS networks initially needed more base stations close together. For full UMTS with video features, a base station was needed every 1 to 1.5 kilometers. This was true when only the 2100 MHz band was used. However, with more use of lower-frequency bands (like 850 and 900 MHz), this is no longer the case. This has led to more lower-band networks being built since 2006.

Even with newer technologies and low-band UMTS, making calls and using data on UMTS uses more power than on similar GSM networks. Apple Inc. said that UMTS power use was why the first iPhone only supported EDGE. Their iPhone 3G had half the talk time on UMTS compared to GSM. Other phone makers also show different battery lives for UMTS and GSM modes. As battery and network technology improve, this problem is getting smaller.

Security Concerns

As early as 2008, it was known that mobile networks could be used to secretly find out where users were. In August 2014, the Washington Post reported that surveillance systems were being widely sold. These systems used Signalling System No. 7 (SS7) protocols to locate people anywhere in the world.

In December 2014, news came out that SS7's own features could be used for spying. This was due to its weak security. It could be used to listen to calls in real time or record encrypted calls and texts to decrypt later. It could also be used to trick users and phone companies.

Deutsche Telekom and Vodafone said they had fixed problems in their networks. But they also said the issue was global and needed a solution for the entire telecommunication system.

UMTS Versions (Releases)

UMTS has been updated over time with different "releases." Each release adds new features and improves existing ones.

Release '99

Allows different ways to send data (bearer services).
Supports 64 kbit/s for circuit-switched calls.
Supports 384 kbit/s for packet-switched data (like internet).
Includes location services.
Call service works with GSM and uses USIM cards.
Improves voice quality.
Uses the 2.1 GHz frequency.

Release 4

Adds Edge radio.
Includes multimedia messaging.
Improves location services.
Adds IP Multimedia Services (IMS).
Includes TD-SCDMA (a type of UTRA-TDD).

Release 5

Adds IP Multimedia Subsystem (IMS).
Uses IPv6 for internet traffic in the radio network.
Improves other parts like GERAN.
Adds HSDPA for faster downloads.

Release 6

Integrates with WLAN (Wi-Fi).
Allows multimedia broadcasting and multicasting.
Further improves IMS.
Adds HSUPA for faster uploads.

Release 7

Enhances Layer 2.
Uses 64 QAM and MIMO for better performance.
Allows voice calls over HSPA.
Adds continuous packet connectivity (CPC).

Release 8

Adds Dual-Cell HSDPA for even faster downloads.

Release 9

Adds Dual-Cell HSUPA for faster uploads.

Images for kids

How a UMTS network is set up
Another view of UMTS network parts
The 3G symbol on an Android phone
A UMTS base station on a building roof
The Nokia 6650, an early (2003) UMTS phone