Universal Mobile Telecommunications System
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Universal Mobile Telecommunications System (UMTS) is one of the third-generation (3G) mobile phone technologies. The currently most common form uses W-CDMA as the underlying air interface, is standardized by the 3GPP, and is the European answer to the ITU IMT-2000 requirements for 3G cellular radio systems.
To differentiate UMTS from competing network technologies, UMTS is sometimes marketed as 3GSM, emphasizing the combination of the 3G nature of the technology and the GSM standard which it was designed to succeed.
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[edit] Preface
This article discusses the technology, business, usage and other aspects encompassing and surrounding UMTS, the 3G successor to GSM which utilizes the W-CDMA air interface and GSM infrastructures. Any issues relating strictly to the W-CDMA interface itself may be better described in the W-CDMA page.
[edit] Features
UMTS, using W-CDMA, supports up to 14.0 Mbit/s data transfer rates in theory (with HSDPA), although at the moment users in deployed networks can expect a performance up to 384 kbit/s for R99 handsets, and 3.6 Mbit/s for HSDPA handsets in the downlink connection. This is still much greater than the 14.4 kbit/s of a single GSM error-corrected circuit switched data channel or multiple 14.4 kbit/s channels in HSCSD, and - in competition to other network technologies such as CDMA2000, PHS or WLAN - offers access to the World Wide Web and other data services on mobile devices.
Precursors to 3G are 2G mobile telephony systems, such as GSM, IS-95, PDC, PHS and other 2G technologies deployed in different countries. In the case of GSM, there is an evolution path from 2G, called GPRS, also known as 2.5G. GPRS supports a much better data rate (up to a theoretical maximum of 140.8kbit/s, though typical rates are closer to 56kbit/s) and is packet switched rather than connection oriented (circuit switched). It is deployed in many places where GSM is used. E-GPRS, or EDGE, is a further evolution of GPRS and is based on more modern coding schemes. With EDGE the actual packet data rates can reach around 180 kbit/s (effective). EDGE systems are often referred as "2.75G Systems".
Since 2006, UMTS networks in many countries have been or are in the process of being upgraded with High Speed Downlink Packet Access (HSDPA), sometimes known as 3.5G. Currently, HSDPA enables downlink transfer speeds of up to 3.6Mbit/s. Work is also progressing on improving the uplink transfer speed with the High-Speed Uplink Packet Access (HSUPA). Longer term, the 3GPP Long Term Evolution project plans to move UMTS to 4G speeds of 100Mbps down and 50Mbps up, using a next generation air interface technology based upon OFDM.
UMTS supports mobile videoconferencing, although experience in Japan and elsewhere has shown that user demand for video calls is not very high.
Other possible uses for UMTS include the downloading of music and video content, as well as live TV.
[edit] Real-world implementations
Beginning in 2003 under the name 3, Hutchison Whampoa gradually launched their startup UMTS networks worldwide including Australia, Austria, Denmark, Hong Kong, Italy, United Kingdom, Ireland and Sweden.
Operators are starting to sell mobile internet products that combine 3G and Wi-Fi in one service. Laptop owners are sold a UMTS modem and given a client program that detects the presence of a Wi-Fi network and switches between 3G and Wi-Fi when available. Initially Wi-Fi was seen as a competitor to 3G, but it is now recognised that as long as the operator owns or leases the Wi-Fi network, they will be able to offer a more competitive product than with UMTS only. Nokia predicted that by the end of 2006 one sixth of all cellular phones would be UMTS devices.
[edit] Africa
The first UMTS network in Africa was launched on the island of Mauritius in November 2004, followed by Vodacom's launch of 3G services in South Africa in December 2004.
In South Africa, UMTS was launched in December 2004 by Vodacom followed in June 2005 by MTN.
also egypt
[edit] The Middle East
UMTS/HSDPA services are being offered by many operators in the Middle East, mainly in United Arab Emirates,Kuwait, Saudi Arabia, Qatar and Bahrain.
In 2006, the first UMTS/HSDPA license was awarded in Egypt.
The Middle East operators are using the primary 2.1 GHz band for the UMTS/HSDPA operation.
[edit] Asia and Pacific
In Singapore, Singapore Telecommunications started their trial during December 2004 and it was successfully launched during March 2005 followed by StarHub and MobileOne.
In the Philippines, UMTS was launched in 2006 by SMART and shortly thereafter by Globe.
Indonesia 3G era began when the government granted 3G licenses to the top three cellular operators: Telkomsel, Excelcom and Indosat. On 14 September 2006, Telkomsel launched its 3G service, followed by Excelcom XL3G on 21 September 2006. The XL3G offers 3G service in 6 major cities (Jakarta, Medan, Batam, Bandung, Surabaya and Denpasar) and allows international 3G roaming to Malaysia, Singapore, Hong Kong and Australia. Other than the first widest 3G service, XL3G also claims the title of the first fastest 3G service in Indonesia, as it offers high speed data access using HSDPA technology.
Government of India is currently evaluating the process of 'Spectrum Allocation' for 3G services. The final decision on the same is to be announced by end Q1 2007. The most likely mode is auctioning of 3G spectrum with a reserve base price. Commercial launch is only expected in 2008.
In Taiwan, Far Eastone launched its WCDMA-based 3G service on July 13 2005, offering 3G services offered by NTT DoCoMo in Japan. Chunghwa Telecom followed suit on 26 July 2005, using a WCDMA 3G network deployed by Nokia. Other local carriers offering 3G services include Taiwan Cellular Corporation and VIBO Telecom.
In South Korea, SK Telecom and KTF both operate UMTS/HSDPA networks since 2006. KTF (and possibly also SK Telecom) use the 2.1 GHz band which allows the use of European GSM/UMTS phones by travelers in case there is a roaming agreement in place between KTF and the home operator of the traveler.
[edit] Australia
In Australia, telecommunication giant Telstra launched their UMTS 3G network named NextG on the 850Mhz band using HSDPA in October 2006. This network covers a claimed 98% of the Australian population since it utilises the existing well established facilities of the 2G CDMA network that it is set to replace. Telstra's NextG network is not to be confused with their existing 3G service which is jointly run with Hutchison in metropolitan areas only on the 2100Mhz band.
[edit] Europe
The first UMTS network in Europe was launched by Manx Telecom on the Isle of Man (a large island in the Irish sea) in 2001. Manx Telecom is part of the O2 group, which is now a subsidiary of Telefonica. O2 used the island as a testbed for 3G technology.
The 3 service was launched in the UK on 3 March 2003 (3/3/3). To meet this early date, this was a soft-launch with limited coverage of the UK initially available.
In December 2003, Mobitel has launched UMTS in Slovenia. T-Mobile launched UMTS in Austria, and began trials in the UK and Germany. Also, in November 2005 the T-Mobile UMTS network in the Netherlands went live (however, this was not a commercial launch, but meant to meet regulatory requirements imposed upon the spectrum auction).
In February 2004, Vodafone began a wide-scale UMTS launch in several European markets, including the UK, Ireland, Germany, The Netherlands and Sweden. In Portugal, UMTS was launched just before the Euro 2004 began.
In Spain, the first operator to kick-off full 3G services was Amena on November 2004, although "early adopter" test were already in place in the country.
The first UMTS network in Poland was launched in 2004 by Plus GSM, but coverage was still limited to Warsaw. In April 2005, Era GSM launched another UMTS network in Warsaw, providing cheap (about 20 euros per month) internet access, among other 3G services. In January 2006 most of top major cities are covered by Era GSM, Orange and Plus GSM.
In Finland, UMTS licenses were provided by the government free of charge. In 2004, Elisa Oyj and TeliaSonera began deploying commercial UMTS networks, and in 2005 Dna Finland began commercial UMTS service.
In Serbia, UMTS was launched on 22 November 2004 by mobile operator Mobtel (now Telenor) but not for commercial purpose - testing only, commercial usage started 27 December 2006 and it was purchase by Mobile telephony of Serbia (Mobilna telefonija Srbije). Officially commercial use of UMTS 3G network in Serbia started with video conversation between Serbian Prime Minister Vojislav Kostunica and singer Zdravko Colic. It is estimated that at that time Mobile telephony of Serbia had ~80,000 users with UMTS capable mobile devices. Telenor Serbia (ex Mobtel) started with commercial usage of UMTS after 2 years testing period on 1 March 2007.
The mainly used UMTS network in Russian Federation is Skylink, which is mostly used by people who spend a lot of time in countryside, in poor GSM coverage areas. Since double format compatible phones appeared in Russia not so long ago, the Benefon UMTS mobile phones are also distributed by Skylink.
[edit] North America
Under a previous agreement with NTT DoCoMo, US provider AT&T Mobility (formerly Cingular) was required to build and market UMTS networks in four major United States cities by the end of 2004. At CTIA 2004, Cingular announced that their 3G network would be a 1900 MHz only implementation of UMTS and would launch by the end of that year as planned. However, since then they have chosen to deploy on 850 MHz and did not release any 1900 MHz-only devices (update: The Cingular 8525 is the first UMTS/HSDPA smart phone to be offered in the United States). As of August 2006, Cingular has deployed UMTS/HSDPA networks in 17 U.S. markets covering 52 cities. Markets include New York (NY), Austin (TX), Baltimore, Boston, Chicago, Dallas, Houston, Las Vegas, Los Angeles, Phoenix, Portland (OR), Salt Lake City, San Diego, San Francisco, San Jose (CA), Seattle, Tacoma, Washington, D.C. and the metropolitan area of Puerto Rico, San Juan. In the latter under the moniker "Telefonía Móvil Universal" (Universal Mobile Telephony).
Roll-out in the US has been limited by a lack of suitable spectrum until recently. The FCC auctioned spectrum in the 1750 and 2150 bands [1], and at least one winner, T-Mobile, has announced a roll-out of a national UMTS network on these frequencies starting in 2007[2].
Previous US roll-outs have suffered due to lack of spectrum, requiring the sharing the 850MHz and 1900MHz bands allocated for cellular communication in the US with existing 1G and 2G networks. The UMTS requirement for 5 MHz frequency slots, much larger than that required for existing networks, can create difficulty for US operators as many are only licensed for 5MHz in each direction in certain areas, and as such cannot run both their existing system and UMTS in the areas affected.
[edit] Technology
The following information does not apply to non-UMTS systems that use the W-CDMA air interface, such as FOMA
UMTS combines the W-CDMA, TD-CDMA, or TD-SCDMA air interfaces, GSM's Mobile Application Part (MAP) core, and the GSM family of speech codecs. In the most popular cellular mobile telephone variant of UMTS, W-CDMA is currently used. Note that other wireless standards use W-CDMA as their air interface, including FOMA.
UMTS over W-CDMA uses a pair of 5 MHz channels. In contrast, the competing CDMA2000 system uses one or more arbitrary 1.25 MHz channels for each direction of communication. UMTS and other W-CDMA systems are widely criticized for their large spectrum usage, which has delayed deployment in countries that acted relatively slowly in allocating new frequencies specifically for 3G services (such as the United States).
The specific frequency bands originally defined by the UMTS standard are 1885-2025 MHz for uplink and 2110-2200 MHz for downlink. In the US, the 1700MHz band will be used instead of 1900MHz - which is already in use - for the uplink by many UMTS operators. Additionally, UMTS is commonly run on 850MHz and 1900MHz (independently, for both the uplink and downlink) in some countries, notably in the US by Cingular Wireless.
For existing GSM operators, it is a simple but costly migration path to UMTS: much of the infrastructure is shared with GSM, but the cost of obtaining new spectrum licenses and overlaying UMTS at existing towers can be prohibitively expensive.
A major difference of UMTS compared to GSM is the air interface forming Generic Radio Access Network (GeRAN). It can be connected to various backbone networks like the Internet, ISDN, GSM or to a UMTS network. GeRAN includes the three lowest layers of OSI model. The network layer (OSI 3) protocols form the Radio Resource Management protocol (RRM). They manage the bearer channels between the mobile terminals and the fixed network including the handovers.
[edit] 3G external modems
Using a cellular router, PCMCIA or USB card, customers are able to access 3G broadband services, regardless of their choice of computer (such as a tablet PC or a PDA). Even the software installs itself from the modem, so that absolutely no knowledge of technology is required to get online in moments.
Cingular sales associate and a helpdesk person confirmed that with certain phones that are capable of 3G, along with Bluetooth 2.0, you can connect multiple Bluetooth capable laptops to the internet. The phone acts like a router, but via Bluetooth rather than wireless networking(802.11) or a usb connection.
[edit] Interoperability and global roaming
At the air interface level, UMTS itself is incompatible with GSM. UMTS phones sold in Europe (as of 2004) are UMTS/GSM dual-mode phones, hence they can also make and receive calls on regular GSM networks. If a UMTS customer travels to an area without UMTS coverage, a UMTS phone will automatically switch to GSM (roaming charges may apply). If the customer travels outside of UMTS coverage during a call, the call will be transparently handed off to available GSM coverage.
Regular GSM phones cannot be used on the UMTS networks.
Softbank (formerly Vodafone Japan, formerly J-Phone) operates a 3G network based on UMTS compatible W-CDMA technology, that launched in December 2002. Lack of investment in the network through 2003 meant that coverage was slow to expand and subscriber numbers remained low. The network was publicly relaunched in October 2004 and again in 2005, and Vodafone now claims network coverage of 99% of the population, while 15% of their subscribers are 3G users.
NTT DoCoMo's 3G network, FOMA, was the first commercial network using W-CDMA since 2002. The first W-CDMA version used by NTT DoCoMo was incompatible with the UMTS standard at the radio level, however USIM cards used by FOMA phones are compatible with GSM phones, so that USIM card based roaming is possible from Japan to GSM areas without any problem. Today the NTT DoCoMo network — as well as all the W-CDMA networks in the world — use the standard version of UMTS, allowing potential global roaming. Whether and under which conditions roaming can actually be used by subscribers depends on the commercial agreements between operators.
All UMTS/GSM dual-mode phones should accept existing GSM SIM cards. Sometimes, you are allowed to roam on UMTS networks using GSM SIM cards from the same provider.
In the United States, UMTS is currently offered by Cingular on 850MHz and 1900MHz, due to the limitations of the spectrum available to them at the time they launched UMTS service. T-Mobile will be rolling out UMTS on the 2100/1700MHz frequencies in mid 2007. Because of the frequencies used, early models of UMTS phones designated for the US will likely not be operable overseas and vice versa; other standards, notably GSM, have faced similar problems, an issue dealt with by the adoption of multi-band phones. Most UMTS licensees seem to consider ubiquitous, transparent global roaming an important issue.
[edit] Spectrum allocation
Over 120 licenses have already been awarded to operators worldwide (as of December 2004), specifying W-CDMA radio access technology that builds on GSM. In Europe, the license process occurred at the end of the technology bubble, and the auction mechanisms for allocation set up in some countries resulted in some extremely high prices being paid, notable in the UK and Germany. In Germany, bidders paid a total 50.8 billion euros for six licenses, two of which were subsequently abandoned and written off by their purchasers (Mobilcom and the Sonera/Telefonica consortium). It has been suggested that these huge license fees have the character of a very large tax paid on income expected 10 years down the road - in any event they put some European telecom operators close to bankruptcy (most notably KPN). Over the last few years some operators have written off some or all of the license costs.
The UMTS spectrum allocated in Europe is already used in North America. The 1900 MHz range is used for 2G (PCS) services, and 2100 MHz range is used for satellite communications. Regulators have however, freed up some of the 2100 MHz range for 3G services, together with the 1700MHz for the uplink. UMTS operators in North America who want to implement a European style 2100/1900MHz system will have to share spectrum with existing 2G services in the 1900 MHz band. 2G GSM services elsewhere use 900 MHz and 1800 MHz and therefore do not share any spectrum with planned UMTS services.
AT&T Wireless launched UMTS services in the United States by the end of 2004 strictly using the existing 1900 MHz spectrum allocated for 2G PCS services. Cingular acquired AT&T Wireless in 2004 and has since then launched UMTS in select US cities. Initial rollout of UMTS in Canada will also be handled exclusively by the 1900 MHz band. T-Mobile's roll-out of UMTS in the US will focus on the 2100/1700MHz bands just auctioned.
Cingular Wireless is rolling out some cities with a UMTS network at 850 MHz to enhance its existing UMTS network at 1900 MHz and now offers subscribers a number of UMTS 850/1900 phones. Telstra has rolled out a UMTS network in Australia under the brand Next G in the 850 MHz band that will eventually replace the Telstra CDMA network and enhance its existing 2100 MHz UMTS network. The 850 MHz band will allow better coverage in rural areas where there are greater distances between subscriber and base station. As current phones on the market do not support the UMTS 850/2100 bands, handset choices available to Telstra subscribers will initially be limited.
[edit] Other competing standards
There are other competing 3G standards, such as FOMA, CDMA2000 and TD-SCDMA, though UMTS can use the latter's air interface standard. FOMA and UMTS similarly share the W-CDMA air interface system.
On the Internet access side, competing systems include WiMAX and Flash-OFDM. Different variants of UMTS compete with different standards. While this article has largely discussed UMTS-FDD, a form oriented for use in conventional cellular-type spectrum, UMTS-TDD, a system based upon a TD-CDMA air interface, is used to provide UMTS service where the uplink and downlink share the same spectrum, and is very efficient at providing asymmetric access. It provides more direct competition with WiMAX and similar Internet-access oriented systems than conventional UMTS.
Both the CDMA2000 and W-CDMA air interface systems are accepted by ITU as part of the IMT-2000 family of 3G standards, in addition to UMTS-TDD's TD-CDMA, Enhanced Data Rates for GSM Evolution (EDGE) and China's own 3G standard, TD-SCDMA.
CDMA2000's narrower bandwidth requirements make it easier than UMTS to deploy in existing spectrum along with legacy standards. In some, but not all, cases, existing GSM operators only have enough spectrum to implement either UMTS or GSM, not both. For example, in the US D, E, and F PCS spectrum blocks, the amount of spectrum available is 5MHz in each direction. A standard UMTS system would saturate that spectrum.
In many markets however, the co-existence issue is of little relevance, as legislative hurdles exist to co-deploying two standards in the same licensed slice of spectrum.
Most GSM operators in North America as well as others around the world have accepted EDGE as a temporary 3G solution. AT&T Wireless launched EDGE nationwide in 2003, Cingular launched EDGE in most markets and T-Mobile USA has launched EDGE nationwide as of October 2005. Rogers Wireless launched nation-wide EDGE service in late 2003 for the Canadian market. Bitė Lietuva (Lithuania) was one of the first operators in Europe to launch EDGE in December 2003. TIM (Italy) launched EDGE in 2004. The benefit of EDGE is that it leverages existing GSM spectrums and is compatible with existing GSM handsets. It is also much easier, quicker, and considerably cheaper for wireless carriers to "bolt-on" EDGE functionality by upgrading their existing GSM transmission hardware to support EDGE than having to install almost all brand-new equipment to deliver UMTS. EDGE provides a short-term upgrade path for GSM operators and directly competes with CDMA2000.
[edit] Problems and issues
There have been and continue to be issues with rollout and continuing development of UMTS:
- overweight handsets with poor battery life;
- problems with handover from UMTS to GSM, connections being dropped or handovers only possible in one direction (UMTS->GSM) with the handset only changing back to UMTS after hanging up, even if UMTS coverage returns;
- initially poor coverage due to the time it takes to build a network;
- for fully fledged UMTS incorporating Video on Demand features, one base station needs to be set up every 1–1.5 km (0.62–0.93 mi). While this is economically feasible in urban areas, it is infeasible in less populated suburban and rural areas;
- Some countries, such as the United States have allocated spectrum that differs from what had been almost universally agreed, preventing the use of existing UMTS-2100 equipment, and requiring the design and manufacture of different equipment for use in these markets. As is the case with GSM today, this presumably will mean that some UMTS equipment will work only in some markets, and some will work only in others, and some more-expensive equipment may be available that works in all markets. It also diminishes the economy of scale and benefit to users from the network effect that would have existed if these few countries had harmonized their regulations with the others.
[edit] See also
- 3GPP: the body that manages the UMTS standard.
- W-CDMA: the primary air interface standard used by UMTS.
- HSDPA, HSUPA: updates to the W-CDMA air interface.
- 3GPP Long Term Evolution, the 3GPP project to evolve UMTS towards 4G capabilities.
- GAN/UMA: A standard for running GSM and UMTS over wireless LANs.
- UMTS-TDD: a variant of UMTS largely used to provide wireless Internet service.
- Subscriber Identity Module
- PDCP
- 3G
Other, non-UMTS, 3G and 4G standards:
- CDMA2000: evolved from the cmdaOne (also known as IS-95, or "CDMA") standard, managed by the 3GPP2
- FOMA
- TD-SCDMA
- WiMAX: a newly emerging wide area wireless technology.
UMTS is an evolution of the GSM mobile phone standard.
Other useful information
- Mobile modem
- Spectral efficiency comparison table
- Code Division Multiple Access
- PN Sequences, a feature of CDMA
- Wi-Fi: a local area wireless technology that is complementary to UMTS.
- Mobile Internet access worldwide lists mobile (mainly UMTS/HSDPA) Internet access solutions worldwide.
[edit] Literature
- Martin Sauter: Communication Systems for the Mobile Information Society, John Wiley, September 2006, ISBN 0-470-02676-6
[edit] References
[edit] External links
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The external links in this article may require cleanup to comply with Wikipedia's content policies. Please improve this article by removing excessive or inappropriate external links. Please remove this tag when this is done. This article has been tagged since December 2006. (talk) |
- GSM/UMTS market statistics from the 'Global mobile suppliers association'
- 3GPP Specifications Numbering Scheme
- 3GPP document listing all UMTS Technical Standards for Release 6 and earlier
- Vocabulary for 3GPP Specifications, up to Release 7
- UMTS Overview on TelecomSpace
- UMTS FAQ on UMTS World d
- Worldwide W-CDMA frequency allocations on UMTS World
- 3G Japan FAQ
- UMTS TDD Alliance The Global UMTS TDD Alliance
- 3GToday.com
- Radio-Electronics.Com Free UMTS / WCDMA tutorial
- 3GSM World Congress
