HOME

TheInfoList




The Universal Mobile Telecommunications System (UMTS) is a
third generation
third generation
mobile cellular system for networks based on the
GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Education * GSM London, a higher education provider * Guildhall School of Music and Drama The Guildhall School of Music and Drama i ...

GSM
standard. Developed and maintained by the
3GPP The 3rd Generation Partnership Project (3GPP) is an umbrella term for a number of standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization (SSO) is an organization ...
(3rd Generation Partnership Project), UMTS is a component of the
International Telecommunication Union 260px, ITU Monument, Bern The International Telecommunication Union is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the ...

International Telecommunication Union
IMT-2000 3G (short for third generation) is the third generation of wireless mobile telecommunications technology. It is the upgrade for 2.5G GPRS and 2.75G EDGE networks, for faster data transfer. This is based on a set of standards used for mobile d ...
standard set and compares with the
CDMA2000 CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling In signal processing Signal processing is an electrical engineering subfield that focu ...
standard set for networks based on the competing
cdmaOne Interim Standard 95 (IS-95) was the first ever CDMA Code-division multiple access (CDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two termina ...
technology. UMTS uses wideband
code-division multiple access Code-division multiple access (CDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminal (telecommunication), terminals connected to the same tr ...
(
W-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Educ ...
) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators. UMTS specifies a complete network system, which includes the
radio access network A radio access network (RAN) is part of a mobile telecommunication system. It implements a radio access technology. Conceptually, it resides between a device such as a mobile phone, a computer, or any remotely controlled machine and provides connect ...
(
UMTS Terrestrial Radio Access Network 350px, UTRAN architecture UTRAN (short for "UMTS Terrestrial Radio Access Network''") is a collective term for the network and equipment that connects mobile handsets to the public telephone network or the Internet. It contains the base stations, ...
, or UTRAN), the
core network A backbone or core network is a part of a computer network A computer network is a group of computers that use a set of common communication protocols over digital signal, digital interconnections for the purpose of sharing resources locat ...
(
Mobile Application Part The Mobile Application Part (MAP) is an SS7 protocol that provides an application layer for the various nodes in GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Education * G ...
, or MAP) and the authentication of users via SIM (
subscriber identity module A GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Education * GSM London, a higher education provider * Guildhall School of Music and Drama The Guildhall School of Music an ...
) cards. The technology described in UMTS is sometimes also referred to as
Freedom of Mobile Multimedia AccessFreedom of Mobile Multimedia Access (FOMA) is the brand name A brand is a name, term, design, symbol or any other feature that identifies one seller's good or service as distinct from those of other sellers. Brands are used in business Bus ...
(FOMA) or 3GSM. Unlike
EDGE Edge or EDGE may refer to: Technology Computing * Edge computing Edge computing is a distributed computing paradigm that brings computation and data storage closer to the sources of data. This is expected to improve response times and save bandw ...

EDGE
(IMT Single-Carrier, based on GSM) and CDMA2000 (IMT Multi-Carrier), UMTS requires new base stations and new frequency allocations.


Features

UMTS supports maximum theoretical data transfer rates of 42 
Mbit/s In telecommunications Telecommunication is the transmission of information by various types of technologies over , radio, , or other systems. It has its origin in the desire of humans for communication over a distance greater than that fea ...
when
Evolved HSPA Evolved High Speed Packet Access, or HSPA+, or HSPA (Plus), or HSPAP is a technical standard for wireless broadband telecommunication. It is the second phase of High Speed Packet Access, HSPA which has been introduced in 3GPP release 7 and being f ...
(HSPA+) is implemented in the network. Users in deployed networks can expect a transfer rate of up to 384 kbit/s for Release '99 (R99) handsets (the original UMTS release), and 7.2 Mbit/s for
High-Speed Downlink Packet Access High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony, mobile Communications protocol, protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performan ...
(HSDPA) handsets in the downlink connection. These speeds are significantly faster than the 9.6 kbit/s of a single GSM error-corrected circuit switched data channel, multiple 9.6 kbit/s channels in
High-Speed Circuit-Switched Data In communications, Circuit Switched Data (CSD) is the original form of data transmission developed for the time-division multiple access (TDMA)-based mobile phone systems like Global System for Mobile Communications (GSM). After 2010 many telecom ...
(HSCSD) and 14.4 kbit/s for CDMAOne channels. 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 High Speed Packet Access (HSPA) is an amalgamation of two mobile protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing 3G mobile telecommunicati ...
. Currently, HSDPA enables
downlink In a telecommunications network A telecommunications network is a group of nodes In general, a node is a localized swelling (a "knot") or a point of intersection (a Vertex (graph theory), vertex). Node may refer to: In mathematics *Vertex (gra ...
transfer speeds of up to 21 Mbit/s. Work is also progressing on improving the uplink transfer speed with the
High-Speed Uplink Packet Access High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony, mobile Communications protocol, protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performan ...
(HSUPA). Longer term, the
3GPP Long Term Evolution In telecommunications Telecommunication is the transmission of information by various types of technologies over , radio, , or other systems. It has its origin in the desire of humans for communication over a distance greater than that ...
(LTE) project plans to move UMTS to 4G speeds of 100 Mbit/s down and 50 Mbit/s up, using a next generation air interface technology based upon
orthogonal frequency-division multiplexing In telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, Optical system, optical, or other Electromagnetism, electromagnetic systems. It has its origin in the desire of human ...
. The first national consumer UMTS networks launched in 2002 with a heavy emphasis on telco-provided mobile applications such as mobile TV and
video calling Videotelephony comprises the technologies for the reception and transmission of audio signal, audio-video signals by users in different locations, for communication between people in real time.McGraw-Hill Concise Encyclopedia of EngineeringVideot ...
. The high data speeds of UMTS are now most often utilised for Internet access: experience in Japan and elsewhere has shown that user demand for video calls is not high, and telco-provided audio/video content has declined in popularity in favour of high-speed access to the World Wide Web either directly on a handset or connected to a computer via
Wi-Fi Wi-Fi () is a family of wireless network A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installa ...

Wi-Fi
,
Bluetooth Bluetooth is a short-range wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor as a medium by which ...

Bluetooth
or
USB Universal Serial Bus (USB) is an industry standard ''Industry Standard'' is a 1982 album by Dixie Dregs, The Dregs. It is their only album featuring vocals (by Alex Ligertwood of Santana (band), Santana and Patrick Simmons of The Doobie Brot ...

USB
.


Air interfaces

UMTS combines three different terrestrial
air interface The air interface, or access mode, is the communication link between the two stations in mobile or wireless communication. The air interface involves both the Physical layer, physical and Data link layer, data link layers (layer 1 and 2) of the OS ...
s,
GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Education * GSM London, a higher education provider * Guildhall School of Music and Drama The Guildhall School of Music and Drama i ...
's
Mobile Application Part The Mobile Application Part (MAP) is an SS7 protocol that provides an application layer for the various nodes in GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Education * G ...
(MAP) core, and the GSM family of
speech codec Speech coding is an application of data compression In signal processing Signal processing is an electrical engineering subfield that focuses on analysing, modifying, and synthesizing signals such as audio signal processing, sound, image p ...
s. The air interfaces are called UMTS Terrestrial Radio Access (UTRA). All air interface options are part of
ITU 260px, ITU Monument, Bern The International Telecommunication Union is a specialized agency of the United Nations responsible for all matters related to information and communication technologies Information and communications technology ...
's
IMT-2000 3G (short for third generation) is the third generation of wireless mobile telecommunications technology. It is the upgrade for 2.5G GPRS and 2.75G EDGE networks, for faster data transfer. This is based on a set of standards used for mobile d ...
. In the currently most popular variant for cellular mobile telephones, W-CDMA (IMT Direct Spread) is used. It is also called "Uu interface", as it links User Equipment to the UMTS Terrestrial Radio Access Network Please note that the terms
W-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Educ ...
,
TD-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
and
TD-SCDMA The Universal Mobile Telecommunications System (UMTS) is a mobile cellular system for networks based on the standard. Developed and maintained by the (3rd Generation Partnership Project), UMTS is a component of the standard set and compares w ...
are misleading. While they suggest covering just a
channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminal (telecommunication), terminals connected to the same transmission medium to transmit over it and to share its capacity. E ...
(namely a variant of
CDMA Code-division multiple access (CDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminal (telecommunication), terminals connected to the same t ...

CDMA
), they are actually the common names for the whole air interface standards.


W-CDMA (UTRA-FDD)

W-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Educ ...
(WCDMA; Wideband
Code-Division Multiple Access Code-division multiple access (CDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminal (telecommunication), terminals connected to the same t ...
), along with UMTS-FDD, UTRA-FDD, or IMT-2000 CDMA Direct Spread is an air interface standard found in
3G
3G
mobile telecommunications Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the li ...
networks. It supports conventional cellular voice, text and MMS services, but can also carry data at high speeds, allowing mobile operators to deliver higher bandwidth applications including streaming and broadband Internet access. W-CDMA uses the
DS-CDMA In telecommunications, direct-sequence spread spectrum (DSSS) is a spread-spectrum modulation technique primarily used to reduce overall signal Interference (communication), interference. The direct-sequence modulation makes the transmitted sign ...
channel access method with a pair of 5 MHz wide channels. In contrast, the competing
CDMA2000 CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling In signal processing Signal processing is an electrical engineering subfield that focu ...
system uses one or more available 1.25 MHz channels for each direction of communication. W-CDMA systems are widely criticized for their large spectrum usage, which 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 A frequency band is an interval (mathematics), interval in the frequency domain, delimited by a lower frequency and an upper frequency. The term may refer to a radio band or an interval of some other spectrum. The frequency range of a system is ...
originally defined by the UMTS standard are 1885–2025 MHz for the mobile-to-base (uplink) and 2110–2200 MHz for the base-to-mobile (downlink). In the US, 1710–1755 MHz and 2110–2155 MHz are used instead, as the 1900 MHz band was already used. While UMTS2100 is the most widely deployed UMTS band, some countries' UMTS operators use the 850 MHz (900 MHz in Europe) and/or 1900 MHz bands (independently, meaning uplink and downlink are within the same band), notably in the US by
AT&T Mobility AT&T Mobility LLC, also known as AT&T Wireless and Trade name, marketed as simply AT&T, is an American telecommunications company. It is a wholly owned subsidiary of AT&T, AT&T Inc. and provides wireless services in the United States, excluding ...

AT&T Mobility
, New Zealand by
Telecom New Zealand Spark New Zealand Limited, more commonly known as Spark, is a New Zealand telecommunications company providing fixed line telephone services, a mobile network, an internet service provider, and is a major ICT provider to NZ businesses (throu ...
on the
XT Mobile Network The XT Mobile Network is a UMTS and LTE mobile network run by Spark New Zealand (formerly Telecom New Zealand). The network was initially built nationwide on WCDMA/UMTS 850 MHz, with 2100 MHz infill in major urban areas. The UMTS netw ...
and in Australia by
Telstra Telstra Corporation Limited is an Australian telecommunications Telecommunication is the transmission of information by various types of technologies over , radio, , or other systems. It has its origin in the desire of humans for commun ...

Telstra
on the
Next G Telstra Corporation Limited is an Australian telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, Optical system, optical, or other Electromagnetism, electromagnetic sy ...
network. Some carriers such as
T-Mobile T-Mobile is the brand name used by the mobile communications subsidiaries of the German telecommunications company Deutsche Telekom, Deutsche Telekom AG. The brand is also active in the Czech Republic (T-Mobile Czech Republic), the Netherlands ( ...
use band numbers to identify the UMTS frequencies. For example, Band I (2100 MHz), Band IV (1700/2100 MHz), and Band V (850 MHz). UMTS-FDD is an acronym for Universal Mobile Telecommunications System (UMTS)
frequency-division duplex A duplex communication system is a Point-to-point (telecommunications), point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many commun ...
ing (FDD) and a
3GPP The 3rd Generation Partnership Project (3GPP) is an umbrella term for a number of standards organization A standards organization, standards body, standards developing organization (SDO), or standards setting organization (SSO) is an organization ...
standardized Standardization or standardisation is the process of implementing and developing technical standard A technical standard is an established norm or requirement for a repeatable technical task. It is usually a formal document that establishes un ...
version of UMTS networks that makes use of frequency-division duplexing for duplexing over an UMTS Terrestrial Radio Access (
UTRA The Universal Mobile Telecommunications System (UMTS) is a 3G, third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Int ...
) air interface. W-CDMA is the basis of Japan's
NTT DoCoMo is a Japanese . The name is officially , "''do communications over the mobile network''", and is also from a ''dokomo'', meaning "everywhere" in Japanese. Docomo provides phone, video phone ( and Some ), (internet), and mail (i-mode mail, Sh ...
's
FOMA Freedom of Mobile Multimedia Access (FOMA) is the of the -based services being offered by the ese . It is an implementation of the (UMTS) and was the world's first 3G mobile data service to commence commercial operations. NTT DoCoMo also off ...
service and the most-commonly used member of the Universal Mobile Telecommunications System (UMTS) family and sometimes used as a synonym for UMTS. It uses the DS-CDMA channel access method and the FDD duplexing method to achieve higher speeds and support more users compared to most previously used
time-division multiple access Time-division multiple access (TDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminal (telecommunication), terminals connected to the sam ...
(TDMA) and
time-division duplex A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...
(TDD) schemes. While not an evolutionary upgrade on the airside, it uses the same
core network A backbone or core network is a part of a computer network A computer network is a group of computers that use a set of common communication protocols over digital signal, digital interconnections for the purpose of sharing resources locat ...
as the
2G
2G
GSM networks deployed worldwide, allowing dual-mode mobile operation along with GSM/
EDGE Edge or EDGE may refer to: Technology Computing * Edge computing Edge computing is a distributed computing paradigm that brings computation and data storage closer to the sources of data. This is expected to improve response times and save bandw ...
; a feature it shares with other members of the UMTS family.


Development

In the late 1990s, W-CDMA was developed by NTT DoCoMo as the air interface for their 3G network
FOMA Freedom of Mobile Multimedia Access (FOMA) is the of the -based services being offered by the ese . It is an implementation of the (UMTS) and was the world's first 3G mobile data service to commence commercial operations. NTT DoCoMo also off ...
. Later NTT DoCoMo submitted the specification to the
International Telecommunication Union 260px, ITU Monument, Bern The International Telecommunication Union is a specialized agency of the United Nations United Nations Specialized Agencies are autonomous organizations working with the United Nations and each other through the ...

International Telecommunication Union
(ITU) as a candidate for the international 3G standard known as IMT-2000. The ITU eventually accepted W-CDMA as part of the IMT-2000 family of 3G standards, as an alternative to CDMA2000, EDGE, and the short range
DECT#REDIRECT Digital enhanced cordless telecommunications {{Redirect category shell, {{R from move ...
system. Later, W-CDMA was selected as an air interface for
UMTS The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Edu ...
. As NTT DoCoMo did not wait for the finalisation of the 3G Release 99 specification, their network was initially incompatible with UMTS. However, this has been resolved by NTT DoCoMo updating their network. Code-Division Multiple Access communication networks have been developed by a number of companies over the years, but development of cell-phone networks based on CDMA (prior to W-CDMA) was dominated by
Qualcomm Qualcomm () is an American multinational corporation headquartered in San Diego, California, and Delaware General Corporation Law, incorporated in Delaware. It creates semiconductors, software, and services related to wireless technology. It ow ...

Qualcomm
, the first company to succeed in developing a practical and cost-effective CDMA implementation for consumer cell phones and its early
IS-95 Interim Standard 95 (IS-95) was the first ever CDMA Code-division multiple access (CDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two termi ...
air interface standard has evolved into the current CDMA2000 (IS-856/IS-2000) standard. Qualcomm created an experimental wideband CDMA system called CDMA2000 3x which unified the W-CDMA (
3GPP The 3rd Generation Partnership Project (3GPP) is an umbrella term for a number of s which develop protocols for . Its best known work is the development and maintenance of: * and related and standards, including and * and related standards, ...
) and CDMA2000 (
3GPP2 The 3rd Generation Partnership Project 2 (3GPP2) is a collaboration between telecommunications associations to make a globally applicable third generation ( 3G) mobile phone system specification within the scope of the ITU 260px, ITU Monumen ...
) network technologies into a single design for a worldwide standard air interface. Compatibility with CDMA2000 would have beneficially enabled roaming on existing networks beyond Japan, since Qualcomm CDMA2000 networks are widely deployed, especially in the Americas, with coverage in 58 countries . However, divergent requirements resulted in the W-CDMA standard being retained and deployed globally. W-CDMA has then become the dominant technology with 457 commercial networks in 178 countries as of April 2012. Several CDMA2000 operators have even converted their networks to W-CDMA for international roaming compatibility and smooth upgrade path to LTE. Despite incompatibility with existing air-interface standards, late introduction and the high upgrade cost of deploying an all-new transmitter technology, W-CDMA has become the dominant standard.


Rationale for W-CDMA

W-CDMA transmits on a pair of 5 MHz-wide radio channels, while CDMA2000 transmits on one or several pairs of 1.25 MHz radio channels. Though W-CDMA does use a direct-sequence CDMA transmission technique like CDMA2000, W-CDMA is not simply a wideband version of CDMA2000. The W-CDMA system is a new design by NTT DoCoMo, and it differs in many aspects from CDMA2000. From an engineering point of view, W-CDMA provides a different balance of trade-offs between cost, capacity, performance, and density; it also promises to achieve a benefit of reduced cost for video phone handsets. W-CDMA may also be better suited for deployment in the very dense cities of Europe and Asia. However, hurdles remain, and
cross-licensingA cross-licensing agreement is a contract A contract is a legally binding agreement that defines and governs the rights and duties between or among its parties Image:'Hip, Hip, Hurrah! Artist Festival at Skagen', by Peder Severin Krøyer (188 ...
of
patent A patent is a type of intellectual property Intellectual property (IP) is a category of property Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depe ...

patent
s between Qualcomm and W-CDMA vendors has not eliminated possible patent issues due to the features of W-CDMA which remain covered by Qualcomm patents. W-CDMA has been developed into a complete set of specifications, a detailed protocol that defines how a mobile phone communicates with the tower, how signals are modulated, how datagrams are structured, and system interfaces are specified allowing free competition on technology elements.


Deployment

The world's first commercial W-CDMA service, FOMA, was launched by NTT DoCoMo in
Japan Japan ( ja, 日本, or , and formally ) is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the land of an in ...

Japan
in 2001. Elsewhere, W-CDMA deployments are usually marketed under the UMTS brand. W-CDMA has also been adapted for use in satellite communications on the U.S.
Mobile User Objective System The Mobile User Objective System is a narrowband military A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically officially authorized and maintaine ...
using geosynchronous satellites in place of cell towers.
J-Phone is a Japanese Japanese may refer to: * Something from or related to Japan , image_flag = Flag of Japan.svg , alt_flag = Centered deep red circle on a white rectangle , image_coat = ...
Japan (once
Vodafone Vodafone Group Plc () is a British Multinational corporation, multinational telecommunications company. Its registered office and global headquarters are in Newbury, Berkshire, England. It predominantly operates services in Asia, Africa, Europe ...
and now
SoftBank Mobile is a Japanese Japanese may refer to: * Something from or related to Japan , image_flag = Flag of Japan.svg , alt_flag = Centered deep red circle on a white rectangle , image_coat = ...
) soon followed by launching their own W-CDMA based service, originally branded "Vodafone Global Standard" and claiming UMTS compatibility. The name of the service was changed to "Vodafone 3G" (now "SoftBank 3G") in December 2004. Beginning in 2003,
Hutchison Whampoa Hutchison Whampoa Limited (HWL) was an investment holding company based in Hong Kong. It was a Fortune Global 500 company and one of the largest companies listed on the Hong Kong Stock Exchange. HWL was an international corporation with a divers ...
gradually launched their upstart UMTS networks. Most countries have, since the ITU approved of the 3G mobile service, either "auctioned" the radio frequencies to the company willing to pay the most, or conducted a "beauty contest" asking the various companies to present what they intend to commit to if awarded the licences. This strategy has been criticised for aiming to drain the cash of operators to the brink of bankruptcy in order to honour their bids or proposals. Most of them have a time constraint for the rollout of the service where a certain "coverage" must be achieved within a given date or the licence will be revoked. Vodafone launched several UMTS networks in Europe in February 2004. MobileOne of
Singapore Singapore (), officially the Republic of Singapore, is a sovereign state, sovereign island city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...

Singapore
commercially launched its 3G (W-CDMA) services in February 2005.
New Zealand New Zealand ( mi, Aotearoa ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
in August 2005 and
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Australia
in October 2005.
AT&T Wireless AT&T Mobility LLC, also known as AT&T Wireless and Trade name, marketed as simply AT&T, is an American telecommunications company. It is a wholly owned subsidiary of AT&T, AT&T Inc. and provides wireless services in the United States, excluding ...
(now a part of
Cingular AT&T Mobility LLC, also known as AT&T Wireless and Trade name, marketed as simply AT&T, is an American telecommunications company. It is a wholly owned subsidiary of AT&T, AT&T Inc. and provides wireless services in the United States, excluding ...
Wireless) has deployed UMTS in several cities. Though advancements in its network deployment have been delayed due to the merger with Cingular, Cingular began offering
HSDPA High Speed Packet Access (HSPA) is an amalgamation of two mobile protocols Protocol may refer to: Sociology and politics * Protocol (politics)Protocol originally (in Late Middle English, c. 15th century) meant the minute or logbook taken at a ...
service in December 2005. Rogers in
Canada Canada is a country in the northern part of North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, ...

Canada
March 2007 has launched HSDPA in the Toronto Golden Horseshoe district on W-CDMA at 850/1900 MHz and plan the launch the service commercial in the top 25 cities October, 2007.
TeliaSonera Telia Company AB is a Swedish multinational telecommunications company and mobile network operator present in Sweden, Finland, Norway, Denmark, Lithuania, Latvia and Estonia. Telia also owns TV4 Media which includes TV4 in Sweden and MTV in Fin ...
opened W-CDMA service in
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the west, Russia to the east, Norway to the north, and is defined by the Gulf of B ...

Finland
October 13, 2004, with speeds up to 384 kbit/s. Availability only in main cities. Pricing is approx. €2/MB.
SK Telecom SK Telecom Co., Ltd. ( or ) is a South Korean wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor ...
and
KTF KT Freetel Co., Ltd. (Korea Telecom Freetel, ko, 주식회사케이티프리텔) was a South Korean telecommunications firm, now merged into Korea Telecom KT Corporation (Hangul: 주식회사 케이티), formerly Korea Telecom, is a South Ko ...
, two largest mobile phone service providers in
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is for ...

South Korea
, have each started offering W-CDMA service in December 2003. Due to poor coverage and lack of choice in handhelds, the W-CDMA service has barely made a dent in the Korean market which was dominated by CDMA2000. By October 2006 both companies are covering more than 90 cities while
SK Telecom SK Telecom Co., Ltd. ( or ) is a South Korean wireless Wireless communication (or just wireless, when the context allows) is the telecommunication, transfer of information between two or more points that do not use an electrical conductor ...
has announced that it will provide nationwide coverage for its WCDMA network in order for it to offer SBSM (Single Band Single Mode) handsets by the first half of 2007. KT Freecel will thus cut funding to its CDMA2000 network development to the minimum. In
Norway Norway, officially the Kingdom of Norway,Names in the official and recognised languages: Bokmål Bokmål (, ; literally "book tongue") is an official written standard for the Norwegian language Norwegian (Norwegian: ''norsk'') is a Nort ...

Norway
,
Telenor Telenor ASA (Oslo Stock Exchange, OSE: TEL, or ) is a Norway, Norwegian majority State-owned enterprise, state-owned multinational corporation, multinational telecommunications company headquartered at Fornebu in Bærum, close to Oslo. It is one ...

Telenor
introduced W-CDMA in major cities by the end of 2004, while their competitor, NetCom, followed suit a few months later. Both operators have 98% national coverage on EDGE, but Telenor has parallel WLAN roaming networks on GSM, where the UMTS service is competing with this. For this reason Telenor is dropping support of their WLAN service in Austria (2006).
Maxis Communications Maxis Communications or Maxis Berhad is a communications service provider in Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, t ...
and
Celcom Celcom Axiata Berhad, Doing business as, DBA Celcom, is the oldest mobile telecommunications provider in Malaysia. Celcom is a member of the Axiata Group, Axiata group of companies. Being one of the very few companies in Malaysia to originall ...
, two mobile phone service providers in
Malaysia Malaysia ( ; ) is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is the geographical southeastern subregion of Asia, consisting of the regions ...

Malaysia
, started offering W-CDMA services in 2005. In
Sweden Sweden ( sv, Sverige ), officially the Kingdom of Sweden ( sv, links=no, Konungariket Sverige ), is a Nordic country The Nordic countries, or the Nordics, are a geographical and cultural region In geography, regions are areas that ...

Sweden
, Telia introduced W-CDMA in March 2004.


UTRA-TDD

UMTS-TDD, an acronym for Universal Mobile Telecommunications System (UMTS) time-division duplexing (TDD), is a 3GPP standardized version of UMTS networks that use UTRA-TDD. UTRA-TDD is a UTRA that uses
time-division duplex A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...
ing for duplexing. While a full implementation of UMTS, it is mainly used to provide Internet access in circumstances similar to those where
WiMAX Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband Wireless broadband is telecommunications technology that provides high-speed wireless Wireless communication (or just wireless, when the context al ...

WiMAX
might be used. UMTS-TDD is not directly compatible with UMTS-FDD: a device designed to use one standard cannot, unless specifically designed to, work on the other, because of the difference in air interface technologies and frequencies used. It is more formally as IMT-2000 CDMA-TDD or IMT 2000 Time-Division (IMT-TD). The two UMTS air interfaces (UTRAs) for UMTS-TDD are TD-CDMA and TD-SCDMA. Both air interfaces use a combination of two channel access methods,
code-division multiple access Code-division multiple access (CDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminal (telecommunication), terminals connected to the same tr ...
(CDMA) and time-division multiple access (TDMA): the frequency band is divided into time slots (TDMA), which are further divided into channels using CDMA spreading codes. These air interfaces are classified as TDD, because time slots can be allocated to either uplink or downlink traffic.


TD-CDMA (UTRA-TDD 3.84 Mcps High Chip Rate (HCR))

TD-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
, an acronym for Time-Division-
Code-Division Multiple Access Code-division multiple access (CDMA) is a channel access method In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminal (telecommunication), terminals connected to the same t ...
, is a channel-access method based on using
spread-spectrum In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or ...
multiple-access (CDMA) across multiple time slots ( TDMA). TD-CDMA is the channel access method for UTRA-TDD HCR, which is an acronym for UMTS Terrestrial Radio Access-Time Division Duplex High Chip Rate. UMTS-TDD's air interfaces that use the TD-CDMA channel access technique are standardized as UTRA-TDD HCR, which uses increments of 5 
MHz The hertz (symbol: Hz) is the derived unit of frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and an ...
of spectrum, each slice divided into 10 ms frames containing fifteen time slots (1500 per second). The time slots (TS) are allocated in fixed percentage for downlink and uplink. TD-CDMA is used to multiplex streams from or to multiple transceivers. Unlike W-CDMA, it does not need separate frequency bands for up- and downstream, allowing deployment in tight
frequency band A frequency band is an interval in the frequency domain, delimited by a lower frequency and an upper frequency. The term may refer to a radio band or an interval of some other spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a c ...
s. TD-CDMA is a part of IMT-2000, defined as IMT-TD Time-Division (IMT CDMA TDD), and is one of the three UMTS air interfaces (UTRAs), as standardized by the 3GPP in UTRA-TDD HCR. UTRA-TDD HCR is closely related to W-CDMA, and provides the same types of channels where possible. UMTS's HSDPA/HSUPA enhancements are also implemented under TD-CDMA. In the United States, the technology have been used for public safety and government use in the
New York City New York, often called New York City to distinguish it from New York State New York is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of ...

New York City
and a few other area. In Japan, IPMobile planned to provide TD-CDMA service in year 2006, but it was delayed, changed to TD-SCDMA, and bankrupt before the service officially started.


TD-SCDMA (UTRA-TDD 1.28 Mcps Low Chip Rate (LCR))

Time-Division Synchronous Code-Division Multiple Access (TD-SCDMA) or UTRA TDD 1.28 Mcps low chip rate (UTRA-TDD LCR) is an air interface found in UMTS mobile telecommunications networks in China as an alternative to W-CDMA. TD-SCDMA uses the TDMA channel access method combined with an adaptive synchronous CDMA component on 1.6 MHz slices of spectrum, allowing deployment in even tighter frequency bands than TD-CDMA. It is standardized by the 3GPP and also referred to as "UTRA-TDD LCR". However, the main incentive for development of this Chinese-developed standard was avoiding or reducing the license fees that have to be paid to non-Chinese patent owners. Unlike the other air interfaces, TD-SCDMA was not part of UMTS from the beginning but has been added in Release 4 of the specification. Like TD-CDMA, TD-SCDMA is known as IMT CDMA TDD within IMT-2000. The term "TD-SCDMA" is misleading. While it suggests covering only a channel access method, it is actually the common name for the whole air interface specification. TD-SCDMA / UMTS-TDD (LCR) networks are incompatible with W-CDMA / UMTS-FDD and TD-CDMA / UMTS-TDD (HCR) networks.


= Objectives

= TD-SCDMA was developed in the People's Republic of China by the Chinese Academy of Telecommunications Technology (CATT), Datang Telecom, and Siemens AG in an attempt to avoid dependence on Western technology. This is likely primarily for practical reasons, since other 3G formats require the payment of patent fees to a large number of Western patent holders. TD-SCDMA proponents also claim it is better suited for densely populated areas. Further, it is supposed to cover all usage scenarios, whereas W-CDMA is optimised for symmetric traffic and macro cells, while TD-CDMA is best used in low mobility scenarios within micro or pico cells. TD-SCDMA is based on spread-spectrum technology which makes it unlikely that it will be able to completely escape the payment of license fees to western patent holders. The launch of a national TD-SCDMA network was initially projected by 2005 but only reached large scale commercial trials with 60,000 users across eight cities in 2008. On January 7, 2009, China granted a TD-SCDMA 3G licence to China Mobile. On September 21, 2009, China Mobile officially announced that it had 1,327,000 TD-SCDMA subscribers as of the end of August, 2009. While TD is primarily a China-only system, it may well be exported to developing countries. It is likely to be replaced with a newer TD-LTE system over the next 5 years.


= Technical highlights

= TD-SCDMA uses TDD, in contrast to the FDD scheme used by
W-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Educ ...
. By dynamically adjusting the number of timeslots used for downlink and uplink, the system can more easily accommodate asymmetric traffic with different data rate requirements on downlink and uplink than FDD schemes. Since it does not require paired spectrum for downlink and uplink, spectrum allocation flexibility is also increased. Using the same carrier frequency for uplink and downlink also means that the channel condition is the same on both directions, and the base station can deduce the downlink channel information from uplink channel estimates, which is helpful to the application of beamforming techniques. TD-SCDMA also uses TDMA in addition to the CDMA used in WCDMA. This reduces the number of users in each timeslot, which reduces the implementation complexity of multiuser detection and beamforming schemes, but the non-continuous transmission also reduces coverage (telecommunication), coverage (because of the higher peak power needed), mobility (because of lower power control frequency) and complicates radio resource management algorithms. The "S" in TD-SCDMA stands for "synchronous", which means that uplink signals are synchronized at the base station receiver, achieved by continuous timing adjustments. This reduces the Interference (communication), interference between users of the same timeslot using different codes by improving the Orthogonality#Communications, orthogonality between the codes, therefore increasing system capacity, at the cost of some hardware complexity in achieving uplink synchronization.


= History

= On January 20, 2006, Ministry of Information Industry of the People's Republic of China formally announced that TD-SCDMA is the country's standard of 3G mobile telecommunication. On February 15, 2006, a timeline for deployment of the network in China was announced, stating pre-commercial trials would take place starting after completion of a number of test networks in select cities. These trials ran from March to October, 2006, but the results were apparently unsatisfactory. In early 2007, the Chinese government instructed the dominant cellular carrier, China Mobile, to build commercial trial networks in eight cities, and the two fixed-line carriers, China Telecom and China Netcom, to build one each in two other cities. Construction of these trial networks was scheduled to finish during the fourth quarter of 2007, but delays meant that construction was not complete until early 2008. The standard has been adopted by 3GPP since Rel-4, known as "UTRA TDD 1.28Mbps Option". On March 28, 2008, China Mobile Group announced TD-SCDMA "commercial trials" for 60,000 test users in eight cities from April 1, 2008. Networks using other 3G standards (WCDMA and CDMA2000 EV/DO) had still not been launched in China, as these were delayed until TD-SCDMA was ready for commercial launch. In January 2009, the Ministry of Industry and Information Technology of the People's Republic of China, Ministry of Industry and Information Technology (MIIT) in China took the unusual step of assigning licences for 3 different third-generation mobile phone standards to three carriers in a long-awaited step that is expected to prompt $41 billion in spending on new equipment. The Chinese-developed standard, TD-SCDMA, was assigned to China Mobile, the world's biggest phone carrier by subscribers. That appeared to be an effort to make sure the new system has the financial and technical backing to succeed. Licences for two existing 3G standards, W-CDMA and Evolution-Data Optimized, CDMA2000 1xEV-DO, were assigned to China Unicom and China Telecom, respectively. Third-generation, or 3G, technology supports Web surfing, wireless video and other services and the start of service is expected to spur new revenue growth. The technical split by MIIT has hampered the performance of China Mobile in the 3G market, with users and China Mobile engineers alike pointing to the lack of suitable handsets to use on the network. Deployment of base stations has also been slow, resulting in lack of improvement of service for users. The network connection itself has consistently been slower than that from the other two carriers, leading to a sharp decline in market share. By 2011 China Mobile has already moved its focus onto TD-LTE. Gradual closures of TD-SCDMA stations started in 2016.


= Frequency bands & Deployments

= The following is a list of mobile telephony, mobile telecommunications networks using third-generation TD-SCDMA / UMTS-TDD (LCR) technology.


Unlicensed UMTS-TDD

In Europe, European Conference of Postal and Telecommunications Administrations, CEPT allocated the 2010–2020 MHz range for a variant of UMTS-TDD designed for unlicensed, self-provided use. Some telecom groups and jurisdictions have proposed withdrawing this service in favour of licensed UMTS-TDD, due to lack of demand, and lack of development of a UMTS TDD air interface technology suitable for deployment in this band.


Comparison with UMTS-FDD

Ordinary UMTS uses UTRA-FDD as an air interface and is known as UMTS-FDD. UMTS-FDD uses W-CDMA for multiple access and
frequency-division duplex A duplex communication system is a Point-to-point (telecommunications), point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many commun ...
for duplexing, meaning that the up-link and down-link transmit on different frequencies. UMTS is usually transmitted on frequencies assigned for 1G, , or 3G mobile telephone service in the countries of operation. UMTS-TDD uses time-division duplexing, allowing the up-link and down-link to share the same spectrum. This allows the operator to more flexibly divide the usage of available spectrum according to traffic patterns. For ordinary phone service, you would expect the up-link and down-link to carry approximately equal amounts of data (because every phone call needs a voice transmission in either direction), but Internet-oriented traffic is more frequently one-way. For example, when browsing a website, the user will send commands, which are short, to the server, but the server will send whole files, that are generally larger than those commands, in response. UMTS-TDD tends to be allocated frequency intended for mobile/wireless Internet services rather than used on existing cellular frequencies. This is, in part, because TDD duplexing is not normally allowed on Mobile phone, cellular, Personal Communications Service, PCS/PCN, and 3G frequencies. TDD technologies open up the usage of left-over unpaired spectrum. Europe-wide, several bands are provided either specifically for UMTS-TDD or for similar technologies. These are 1900 MHz and 1920 MHz and between 2010 MHz and 2025 MHz. In several countries the 2500-2690 MHz band (also known as MMDS in the USA) have been used for UMTS-TDD deployments. Additionally, spectrum around the 3.5 GHz range has been allocated in some countries, notably Britain, in a technology-neutral environment. In the Czech Republic UTMS-TDD is also used in a frequency range around 872 MHz.


Deployment

UMTS-TDD has been deployed for public and/or private networks in at least nineteen countries around the world, with live systems in, amongst other countries, Australia, Czech Republic, France, Germany, Japan, New Zealand, Botswana, South Africa, the UK, and the USA. Deployments in the US thus far have been limited. It has been selected for a public safety support network used by emergency responders in New York, but outside of some experimental systems, notably one from Nextel, thus far the WiMAX standard appears to have gained greater traction as a general mobile Internet access system.


Competing standards

A variety of Internet-access systems exist which provide broadband speed access to the net. These include WiMAX and HIPERMAN. UMTS-TDD has the advantages of being able to use an operator's existing UMTS/GSM infrastructure, should it have one, and that it includes UMTS modes optimized for circuit switching should, for example, the operator want to offer telephone service. UMTS-TDD's performance is also more consistent. However, UMTS-TDD deployers often have regulatory problems with taking advantage of some of the services UMTS compatibility provides. For example, UMTS-TDD spectrum in the UK cannot be used to provide telephone service, though the regulator OFCOM is discussing the possibility of allowing it at some point in the future. Few operators considering UMTS-TDD have existing UMTS/GSM infrastructure. Additionally, the WiMAX and HIPERMAN systems provide significantly larger bandwidths when the mobile station is in close proximity to the tower. Like most mobile Internet access systems, many users who might otherwise choose UMTS-TDD will find their needs covered by the ad hoc collection of unconnected Wi-Fi access points at many restaurants and transportation hubs, and/or by Internet access already provided by their mobile phone operator. By comparison, UMTS-TDD (and systems like WiMAX) offers mobile, and more consistent, access than the former, and generally faster access than the latter.


Radio access network

UMTS also specifies the Universal Terrestrial Radio Access Network (UTRAN), which is composed of multiple base stations, possibly using different terrestrial air interface standards and frequency bands. UMTS and GSM/EDGE can share a Core Network (CN), making UTRAN an alternative radio access network to GERAN (GSM/EDGE RAN), and allowing (mostly) transparent switching between the RANs according to available coverage and service needs. Because of that, UMTS's and GSM/EDGE's radio access networks are sometimes collectively referred to as UTRAN/GERAN. UMTS networks are often combined with GSM/EDGE, the latter of which is also a part of IMT-2000. The UE (User equipment, User Equipment) interface of the Radio access network, RAN (Radio Access Network) primarily consists of Radio Resource Control, RRC (Radio Resource Control), PDCP (Packet Data Convergence Protocol), Radio Link Control, RLC (Radio Link Control) and MAC (Media Access Control) protocols. RRC protocol handles connection establishment, measurements, radio bearer services, security and handover decisions. RLC protocol primarily divides into three Modes Transparent Mode (TM), Unacknowledge Mode (UM), Acknowledge Mode (AM). The functionality of AM entity resembles TCP operation whereas UM operation resembles UDP operation. In TM mode, data will be sent to lower layers without adding any header to Service data unit, SDU of higher layers. MAC handles the scheduling of data on air interface depending on higher layer (RRC) configured parameters. The set of properties related to data transmission is called Radio Bearer (RB). This set of properties decides the maximum allowed data in a TTI (Transmission Time Interval). RB includes RLC information and RB mapping. RB mapping decides the mapping between RB<->logical channel<->transport channel. Signaling messages are sent on Signaling Radio Bearers (SRBs) and data packets (either CS or PS) are sent on data RBs. RRC and Non Access Stratum, NAS messages go on SRBs. Security includes two procedures: integrity and ciphering. Integrity validates the resource of messages and also makes sure that no one (third/unknown party) on the radio interface has modified the messages. Ciphering ensures that no one listens to your data on the air interface. Both integrity and ciphering are applied for SRBs whereas only ciphering is applied for data RBs.


Core network

With Mobile Application Part, UMTS uses the same core network standard as GSM/EDGE. This allows a simple migration for existing GSM operators. However, the migration path to UMTS is still costly: while much of the core infrastructure is shared with GSM, the cost of obtaining new spectrum licenses and overlaying UMTS at existing towers is high. The CN can be connected to various backbone networks, such as the Internet or an Integrated Services Digital Network (ISDN) telephone network. UMTS (and GERAN) include the three lowest layers of OSI model. The network layer (OSI 3) includes the Radio Resource Management protocol (RRM) that manages the bearer channels between the mobile terminals and the fixed network, including the handovers.


Frequency bands and channel bandwidths


UARFCN

A UARFCN (abbreviation for UTRA Absolute Radio Frequency Channel Number, where UTRA stands for UMTS Terrestrial Radio Access) is used to identify a frequency in the UMTS frequency bands. Typically channel number is derived from the frequency in MHz through the formula Channel Number = Frequency * 5. However, this is only able to represent channels that are centered on a multiple of 200 kHz, which do not align with licensing in North America. 3GPP added several special values for the common North American channels.


Spectrum allocation

Over 130 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 tail end of the technology bubble, and the auction mechanisms for allocation set up in some countries resulted in some extremely high prices being paid for the original 2100 MHz licenses, notably in the UK and Germany. In Germany, bidders paid a total €50.8 billion 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 future income expected many years down the road. In any event, the high prices paid 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. Between 2007 and 2009, all three Finnish carriers began to use 900 MHz UMTS in a shared arrangement with its surrounding 2G GSM base stations for rural area coverage, a trend that is expected to expand over Europe in the next 1–3 years. The 2100 MHz band (downlink around 2100 MHz and uplink around 1900 MHz) allocated for UMTS in Europe and most of Asia is already used in North America. The 1900 MHz range is used for 2G (Personal Communications Service, 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 a different range around 1700 MHz for the uplink. 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. Cingular renamed itself AT&T Mobility and rolled 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 dual-band UMTS 850/1900 phones. T-Mobile's rollout of UMTS in the US was originally focused on the 1700 MHz band. However, T-Mobile has been moving users from 1700 MHz to 1900 MHz (PCS) in order to reallocate the spectrum to 4G LTE services. In Canada, UMTS coverage is being provided on the 850 MHz and 1900 MHz bands on the Rogers and Bell-Telus networks. Bell and Telus share the network. Recently, new providers Wind Mobile, Mobilicity and Videotron have begun operations in the 1700 MHz band. In 2008, Australian telco Telstra replaced its existing CDMA network with a national UMTS-based 3G network, branded as NextG, operating in the 850 MHz band. Telstra currently provides UMTS service on this network, and also on the 2100 MHz UMTS network, through a co-ownership of the owning and administrating company 3GIS. This company is also co-owned by Hutchison 3G, Hutchison 3G Australia, and this is the primary network used by their customers. Optus is currently rolling out a 3G network operating on the 2100 MHz band in cities and most large towns, and the 900 MHz band in regional areas. Vodafone Australia, Vodafone is also building a 3G network using the 900 MHz band. In India, BSNL has started its 3G services since October 2009, beginning with the larger cities and then expanding over to smaller cities. The 850 MHz and 900 MHz bands provide greater coverage compared to equivalent 1700/1900/2100 MHz networks, and are best suited to regional areas where greater distances separate base station and subscriber. Carriers in South America are now also rolling out 850 MHz networks.


Interoperability and global roaming

UMTS phones (and data cards) are highly portable they have been designed to roam easily onto other UMTS networks (if the providers have roaming agreements in place). In addition, almost all UMTS phones are UMTS/GSM dual-mode devices, so if a UMTS phone travels outside of UMTS coverage during a call the call may be transparently handed off to available GSM coverage. Roaming charges are usually significantly higher than regular usage charges. Most UMTS licensees consider ubiquitous, transparent global roaming an important issue. To enable a high degree of interoperability, UMTS phones usually support several different frequencies in addition to their GSM fallback. Different countries support different UMTS frequency bands Europe initially used 2100 MHz while the most carriers in the USA use 850 MHz and 1900 MHz. T-Mobile has launched a network in the US operating at 1700 MHz (uplink) /2100 MHz (downlink), and these bands also have been adopted elsewhere in the US and in Canada and Latin America. A UMTS phone and network must support a common frequency to work together. Because of the frequencies used, early models of UMTS phones designated for the United States will likely not be operable elsewhere and vice versa. There are now 11 different frequency combinations used around the world including frequencies formerly used solely for 2G services. UMTS phones can use a Universal Subscriber Identity Module, USIM (based on GSM's SIM card) and also work (including UMTS services) with GSM SIM cards. This is a global standard of identification, and enables a network to identify and authenticate the (U)SIM in the phone. Roaming agreements between networks allow for calls to a customer to be redirected to them while roaming and determine the services (and prices) available to the user. In addition to user subscriber information and authentication information, the (U)SIM provides storage space for phone book contact. Handsets can store their data on their own memory or on the (U)SIM card (which is usually more limited in its phone book contact information). A (U)SIM can be moved to another UMTS or GSM phone, and the phone will take on the user details of the (U)SIM, meaning it is the (U)SIM (not the phone) which determines the phone number of the phone and the billing for calls made from the phone. Japan was the first country to adopt 3G technologies, and since they had not used GSM previously they had no need to build GSM compatibility into their handsets and their 3G handsets were smaller than those available elsewhere. In 2002, NTT DoCoMo's FOMA 3G network was the first commercial UMTS network using a pre-release specification, it was initially incompatible with the UMTS standard at the radio level but used standard USIM cards, meaning USIM card based roaming was possible (transferring the USIM card into a UMTS or GSM phone when travelling). Both NTT DoCoMo and SoftBank Mobile (which launched 3G in December 2002) now use standard UMTS.


Handsets and modems

Image:Nokia6650 unlocked.jpg, The Nokia 6650, an early (2003) UMTS handset All of the major 2G phone manufacturers (that are still in business) are now manufacturers of 3G phones. The early 3G handsets and modems were specific to the frequencies required in their country, which meant they could only roam to other countries on the same 3G frequency (though they can fall back to the older GSM standard). Canada and USA have a common share of frequencies, as do most European countries. The article UMTS frequency bands is an overview of UMTS network frequencies around the world. 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 computer, tablet PC or a Personal digital assistant, PDA). Some software self installing, installs itself from the modem, so that in some cases absolutely no knowledge of technology is required to get online in moments. Using a phone that supports 3G and Bluetooth 2.0, multiple Bluetooth-capable laptops can be connected to the Internet. Some smartphones can also act as a mobile WLAN access point. There are very few 3G phones or modems available supporting all 3G frequencies (UMTS850/900/1700/1900/2100 MHz). In 2010, Nokia released a range of phones with Multi-band, Pentaband 3G coverage, including the Nokia N8, N8 and Nokia E7-00, E7. Many other phones are offering more than one band which still enables extensive roaming. For example, Apple's iPhone 4 contains a quadband chipset operating on 850/900/1900/2100 MHz, allowing usage in the majority of countries where UMTS-FDD is deployed.


Other competing standards

The main competitor to UMTS is CDMA2000 (IMT-MC), which is developed by the 3GPP2. Unlike UMTS, CDMA2000 is an evolutionary upgrade to an existing 2G standard, cdmaOne, and is able to operate within the same frequency allocations. This and CDMA2000's narrower bandwidth requirements make it easier to deploy in existing spectra. 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 5 MHz in each direction. A standard UMTS system would saturate that spectrum. Where CDMA2000 is deployed, it usually co-exists with UMTS. 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. Another competitor to UMTS is
EDGE Edge or EDGE may refer to: Technology Computing * Edge computing Edge computing is a distributed computing paradigm that brings computation and data storage closer to the sources of data. This is expected to improve response times and save bandw ...

EDGE
(IMT-SC), which is an evolutionary upgrade to the 2G GSM system, leveraging existing GSM spectrums. 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 rather than having to install almost all brand-new equipment to deliver UMTS. However, being developed by 3GPP just as UMTS, EDGE is not a true competitor. Instead, it is used as a temporary solution preceding UMTS roll-out or as a complement for rural areas. This is facilitated by the fact that GSM/EDGE and UMTS specification are jointly developed and rely on the same core network, allowing dual-mode operation including vertical handovers. China's
TD-SCDMA The Universal Mobile Telecommunications System (UMTS) is a mobile cellular system for networks based on the standard. Developed and maintained by the (3rd Generation Partnership Project), UMTS is a component of the standard set and compares w ...
standard is often seen as a competitor, too. TD-SCDMA has been added to UMTS' Release 4 as UTRA-TDD 1.28 Mcps Low Chip Rate (UTRA-TDD LCR). Unlike
TD-CDMA The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the Inte ...
(UTRA-TDD 3.84 Mcps High Chip Rate, UTRA-TDD HCR) which complements W-CDMA (UTRA-FDD), it is suitable for both micro and macro cells. However, the lack of vendors' support is preventing it from being a real competitor. While DECT is technically capable of competing with UMTS and other cellular networks in densely populated, urban areas, it has only been deployed for domestic cordless phones and private in-house networks. All of these competitors have been accepted by ITU as part of the IMT-2000 family of 3G standards, along with UMTS-FDD. On the Internet access side, competing systems include WiMAX and Flash-OFDM.


Migrating from GSM/GPRS to UMTS

From a GSM/GPRS network, the following network elements can be reused: * Home Location Register (HLR) * Visitor Location Register (VLR) * Equipment Identity Register (EIR) * Mobile Switching Center (MSC) (vendor dependent) * Authentication Center (AUC) * Serving GPRS Support Node (SGSN) (vendor dependent) * Gateway GPRS Support Node (GGSN) From a GSM/GPRS communication radio network, the following elements cannot be reused: * Base station controller (BSC) * Base transceiver station (BTS) They can remain in the network and be used in dual network operation where 2G and 3G networks co-exist while network migration and new 3G terminals become available for use in the network. The UMTS network introduces new network elements that function as specified by 3GPP: * Node B (base transceiver station) * Radio Network Controller (RNC) * Media Gateway (MGW) The functionality of MSC and SGSN changes when going to UMTS. In a GSM system the MSC handles all the circuit switched operations like connecting A- and B-subscriber through the network. SGSN handles all the packet switched operations and transfers all the data in the network. In UMTS the Media gateway (MGW) take care of all data transfer in both circuit and packet switched networks. MSC and SGSN control MGW operations. The nodes are renamed to MSC-server and GSN-server.


Problems and issues

Some countries, including the United States, have allocated spectrum differently from the International Telecommunication Union, ITU recommendations, so that the standard bands most commonly used for UMTS (UMTS-2100) have not been available. In those countries, alternative bands are used, preventing the interoperability of existing UMTS-2100 equipment, and requiring the design and manufacture of different equipment for the use in these markets. As is the case with GSM900 today, standard UMTS 2100 MHz equipment will not work in those markets. However, it appears as though UMTS is not suffering as much from handset band compatibility issues as GSM did, as many UMTS handsets are multi-band in both UMTS and GSM modes. Penta-band (850, 900, 1700, 2100, and 1900 MHz bands), quad-band GSM (850, 900, 1800, and 1900 MHz bands) and tri-band UMTS (850, 1900, and 2100 MHz bands) handsets are becoming more commonplace. In its early days, UMTS had problems in many countries: Overweight handsets with poor battery life were first to arrive on a market highly sensitive to weight and form factor. The Motorola A830, a debut handset on Hutchison's 3 network, weighed more than 200 grams and even featured a detachable camera to reduce handset weight. Another significant issue involved call reliability, related to problems with handover from UMTS to GSM. Customers found their connections being dropped as handovers were possible only in one direction (UMTS → GSM), with the handset only changing back to UMTS after hanging up. In most networks around the world this is no longer an issue. Compared to GSM, UMTS networks initially required a higher base station density. For fully-fledged UMTS incorporating video on demand features, one base station needed to be set up every 1–1.5 km (0.62–0.93 mi). This was the case when only the 2100 MHz band was being used, however with the growing use of lower-frequency bands (such as 850 and 900 MHz) this is no longer so. This has led to increasing rollout of the lower-band networks by operators since 2006. Even with current technologies and low-band UMTS, telephony and data over UMTS requires more power than on comparable GSM networks. Apple Inc. cited UMTS power consumption as the reason that the first generation iPhone only supported EDGE. Their release of the iPhone 3G quotes talk time on UMTS as half that available when the handset is set to use GSM. Other manufacturers indicate different battery lifetime for UMTS mode compared to GSM mode as well. As battery and network technology improve, this issue is diminishing.


Security issues

As early as 2008, it was known that carrier networks can be used to surreptitiously gather user location information. In August 2014, the Washington Post reported on widespread marketing of surveillance systems using Signalling System No. 7 (SS7) protocols to locate callers anywhere in the world. In December 2014, news broke that SS7's very own functions can be repurposed for surveillance, because of its lax security, in order to listen to calls in real time or to record encrypted calls and texts for later decryption, or to defraud users and cellular carriers. Deutsche Telekom and Vodafone declared the same day that they had fixed gaps in their networks, but that the problem is global and can only be fixed with a telecommunication system-wide solution.


Releases

The evolution of UMTS progresses according to planned releases. Each release is designed to introduce new features and improve upon existing ones.


Release '99

* Radio Bearer in UMTS, Bearer services * 64 kbit/s circuit switch * 384 kbit/s packet switched * Location services * Call service: compatible with Global System for Mobile Communications (
GSM GSM (Global System for Mobile communications) is a European standard for mobile devices. GSM may also refer to: Education * GSM London, a higher education provider * Guildhall School of Music and Drama The Guildhall School of Music and Drama i ...

GSM
), based on Universal Subscriber Identity Module (USIM) * Voice quality features Tandem Free Operation * Frequency 2.1 GHz


Release 4

* Edge radio * Multimedia messaging * MExE (Mobile Execution Environment) * Improved location services * IP Multimedia Services (IMS) * TD-SCDMA (UTRA-TDD 1.28 Mcps low chip rate)


Release 5

* IP Multimedia Subsystem (IMS) * IPv6, IP transport in UTRAN * Improvements in GERAN, MExE, etc. * HSDPA


Release 6

* Wireless LAN, WLAN integration * Multimedia broadcast and multicast * Improvements in IMS * HSUPA * Fractional DPCH


Release 7

* Enhanced L2 * 64 QAM, MIMO * Voice over High Speed Packet Access, HSPA * CPC continuous packet connectivity * FRLC Flexible RLC


Release 8

* High-Speed Downlink Packet Access#Dual-Cell, Dual-Cell HSDPA


Release 9

* DC-HSUPA, Dual-Cell HSUPA


See also


References


Citations


Bibliography

* Martin Sauter: ''Communication Systems for the Mobile Information Society'', John Wiley, September 2006, . * Ahonen and Barrett (editors), ''Services for UMTS'' (Wiley, 2002) first book on the services for 3G, . * Holma and Toskala (editors), ''WCDMA for UMTS'', (Wiley, 2000) first book dedicated to 3G technology, . * Kreher and Ruedebusch, ''UMTS Signaling: UMTS Interfaces, Protocols, Message Flows and Procedures Analyzed and Explained'' (Wiley 2007), . * Laiho, Wacker and Novosad, ''Radio Network Planning and Optimization for UMTS'' (Wiley, 2002) first book on radio network planning for 3G, . * Muratore, Flavio. UMTS: mobile communications for the future. John Wiley & Sons, Inc., 2000. .


Documentation


3GPP specification series 25
Radio aspects of 3G, including UMTS
TS 25.201 Physical Layer General Description
Describes basic differences between FDD and TDD.
TS 25.211 Physical channels and mapping of transport channels onto physical channels (FDD)

TS 25.221 Physical channels and mapping of transport channels onto physical channels (TDD)

TS 25.212 Multiplexing and channel coding (FDD)

TS 25.222 Multiplexing and channel coding (TDD)

TS 25.213 Spreading and modulation (FDD)

TS 25.223 Spreading and modulation (TDD)

TS 25.214 Physical layer procedures (FDD)

TS 25.224 Physical layer procedures (TDD)

TS 25.215 Physical layer Measurements (FDD)

TS 25.225 Physical layer Measurements (TDD)


External links



3rd Generation Partnership Project Standard




UMTS LTE Link Budget Comparison


on UMTS World

on UMTS World
UMTS TDD Alliance
The Global UMTS TDD Alliance
3GSM World Congress

UMTS Provider Chart

LTE Encyclopedia

TD-SCDMA Forum

TD-SCDMA Industry Alliance

UMTS FAQ
{{Authority control Telecommunications-related introductions in 2002 3GPP standards Bandplans Metropolitan area networks Mobile telecommunications Mobile telecommunications standards Network access UMTS Videotelephony Wireless networking