Universal Mobile Telecommunications System

Universal Adaptable Telecommunications Arrangement (UMTS) is a third bearing adaptable cellular technology for networks based on the GSM standard. Developed by the 3GPP (3rd Bearing Partnership Project), UMTS is a basic of the International Telecommunications Union IMT-2000 accepted set and compares with the CDMA2000 accepted set for networks based on the aggressive cdmaOne technology. UMTS employs wideband cipher analysis assorted admission (W-CDMA) radio admission technology to action greater ashen ability and bandwidth to adaptable arrangement operators. UMTS specifies a complete arrangement system, accoutrement the radio admission arrangement (UMTS Terrestrial Radio Admission Network, or UTRAN), the amount arrangement (Mobile Application Part, or MAP) and the affidavit of users via SIM cards (Subscriber Identity Module).

The technology declared in UMTS is sometimes aswell referred to as Freedom of Adaptable Multimedia Admission (FOMA) or 3GSM.1

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

Features

UMTS supports best abstract abstracts alteration ante of 45 Mbit/s if HSPA+ is implemented in the network.2 Users in deployed networks can apprehend a alteration amount of up to 384 kbit/s for R99 handsets, and 7.2 Mbit/s for HSDPA handsets in the downlink connection. These speeds are decidedly faster than the 9.6 kbit/s of a individual GSM error-corrected ambit switched abstracts channel, assorted 9.6 kbit/s channels in HSCSD and 14.4 kbit/s for CDMAOne channels.

Since 2006, UMTS networks in abounding countries accept been or are in the action of getting upgraded with Top Acceleration Downlink Packet Admission (HSDPA), sometimes accepted as 3.5G. Currently, HSDPA enables downlink alteration speeds of up to 21 Mbit/s. Work is aswell advanced on convalescent the uplink alteration acceleration with the High-Speed Uplink Packet Admission (HSUPA). Longer term, the 3GPP Long Appellation Evolution activity affairs to move UMTS to 4G speeds of 100 Mbit/s down and 50 Mbit/s up, application a next bearing air interface technology based aloft erect frequency-division multiplexing.

The aboriginal civic customer UMTS networks launched in 2002 with a abundant accent on telco-provided adaptable applications such as adaptable TV and video calling. The top abstracts speeds of UMTS are now a lot of generally utilised for Internet access: acquaintance in Japan and abroad has apparent that user appeal for video calls is not high, and telco-provided audio/video agreeable has beneath in acceptance in favour of accelerated admission to the World Wide Web - either anon on a handset or affiliated to a computer via Wi-Fi, Bluetooth, Infrared or USB.

Technology

UMTS combines three altered air interfaces, GSM's Adaptable Application Allotment (MAP) core, and the GSM ancestors of accent codecs.

Air interfaces

UMTS provides several altered earthbound air interfaces, alleged UMTS Earthbound Radio Admission (UTRA).3 All air interface options are allotment of ITU's IMT-2000. In the currently a lot of accepted alternative for cellular adaptable telephones, W-CDMA (IMT Direct Spread) is used.

Please agenda that the agreement W-CDMA, TD-CDMA and TD-SCDMA are misleading. While they advance accoutrement just a approach admission adjustment (namely a alternative of CDMA), they are in fact the accepted names for the accomplished air interface standards

W-CDMA (UTRA-FDD)

W-CDMA uses the DS-CDMA approach admission adjustment with a brace of 5 MHz advanced channels. In contrast, the aggressive CDMA2000 arrangement uses one or added accessible 1.25 MHz channels for anniversary administration of communication. W-CDMA systems are broadly criticized for their ample spectrum usage, which has delayed deployment in countries that acted almost boring in allocating new frequencies accurately for 3G casework (such as the United States).

The specific abundance bands originally authentic by the UMTS accepted 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 will be acclimated instead, as the 1900 MHz bandage was already used.5 While UMTS2100 is the a lot of broadly deployed UMTS band, some countries' UMTS operators use the 850 MHz and/or 1900 MHz bands (independently, acceptation uplink and downlink are aural the aforementioned band), conspicuously in the US by AT&T Mobility, New Zealand by Telecom New Zealand on the XT Mobile Arrangement and in Australia by Telstra on the Next G network.

Radio access network

UMTS aswell specifies the Universal Earthbound Radio Admission Arrangement (UTRAN), which is

composed of assorted abject stations, possibly application altered earthbound air interface standards and abundance bands

.

UMTS and GSM/EDGE can allotment a Core Arrangement (CN), authoritative UTRAN an another radio admission arrangement to GERAN (GSM/EDGE RAN), and acceptance (mostly) cellophane switching amid the RANs according to accessible advantage and account needs. Because of that, UMTS' and GSM/EDGE's radio admission networks are sometimes collectively referred to as UTRAN/GERAN.

Core network

With Adaptable Application Part, UMTS uses the aforementioned amount arrangement accepted as GSM/EDGE. This allows a simple clearing for absolute GSM operators. However, the clearing aisle to UMTS is still costly: while abundant of the amount basement is aggregate with GSM, the amount of accepting new spectrum licenses and overlaying UMTS at absolute building is high.

The CN can be affiliated to assorted courage networks like the Internet, ISDN. UMTS (and GERAN) cover the three everyman layers of OSI model. The arrangement band (OSI 3) includes the Radio Resource Management agreement (RRM) that manages the agent channels amid the adaptable terminals and the anchored network, including the handovers.

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 are also being adopted elsewhere in the Americas. 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) 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,8 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

All of the above 2G buzz manufacturers (that are still in business) are now manufacturers of 3G phones. The aboriginal 3G handsets and modems were specific to the frequencies appropriate in their country, which meant they could alone roam to added countries on the aforementioned 3G abundance (though they can abatement aback to the earlier GSM standard). Canada and USA accept a accepted allotment of frequencies, as do a lot of European countries. The commodity UMTS abundance bands is an overview of UMTS arrangement frequencies about the world.

Using a cellular router, PCMCIA or USB card, barter are able to admission 3G broadband services, behindhand of their best of computer (such as a book PC or a PDA). Some software installs itself from the modem, so that in some cases actually no ability of technology is appropriate to get online in moments. Using a buzz that supports 3G and Bluetooth 2.0, assorted Bluetooth-capable laptops can be affiliated to the Internet. Some smartphones can aswell act as a adaptable WLAN admission point.

There are actual few 3G phones or modems accessible acknowledging all 3G frequencies (UMTS850/900/1700/1900/2100 MHz). Nokia has afresh appear a ambit of phones that accept Pentaband 3G coverage, including the N8 and E7. Many added phones are alms added than one bandage which still enables all-encompassing roaming. For example, Apple's iPhone 4 contains a quadband chipset operating on 850/900/1900/2100 MHz, acceptance acceptance in the majority of countries area UMTS-FDD is deployed.

Other competing standards

The capital adversary to UMTS is CDMA2000 (IMT-MC), which is developed by the 3GPP2. Unlike UMTS, CDMA2000 is an evolutionary advancement to an absolute 2G standard, cdmaOne, and is able to accomplish aural the aforementioned abundance allocations. This and CDMA2000's narrower bandwidth requirements accomplish it easier to arrange in absolute spectra. In some, but not all, cases, absolute GSM operators alone accept abundant spectrum to apparatus either UMTS or GSM, not both. For example, in the US D, E, and F PCS spectrum blocks, the bulk of spectrum accessible is 5 MHz in anniversary direction. A accustomed UMTS arrangement would bathe that spectrum. Where CDMA2000 is deployed, it usually co-exists with UMTS. In abounding markets however, the co-existence affair is of little relevance, as aldermanic hurdles abide to co-deploying two standards in the aforementioned accountant allotment of spectrum.

Another adversary to UMTS is EDGE (IMT-SC), which is an evolutionary advancement to the 2G GSM system, leveraging absolute GSM spectrums. It is aswell abundant easier, quicker, and appreciably cheaper for wireless carriers to "bolt-on" EDGE functionality by advance their absolute GSM manual accouterments to abutment EDGE rather than accepting to install about all aboriginal accessories to bear UMTS. However, getting developed by 3GPP just as UMTS, EDGE is not a accurate competitor. Instead, it is acclimated as a acting band-aid above-mentioned UMTS roll-out or as a accompaniment for rural areas. This is facilitated by the actuality that GSM/EDGE and UMTS blueprint are accordingly developed and await on the aforementioned amount network, acceptance dual-mode operation including vertical handovers.

China's TD-SCDMA accustomed is generally apparent 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 (UTRA-TDD 3.84 Mcps High Chip Rate, UTRA-TDD HCR) which complements W-CDMA (UTRA-FDD), it is acceptable for both micro and macro cells. However, the abridgement of vendors' abutment is preventing it from getting a absolute competitor.

While DECT is technically able of aggressive with UMTS and added cellular networks in densely populated, burghal areas, it has alone been deployed for calm cordless phones and clandestine centralized networks.

All of these competitors accept been accustomed by ITU as allotment of the IMT-2000 ancestors of 3G standards, forth with UMTS-FDD.

On the Internet admission side, aggressive systems cover WiMAX and Flash-OFDM.

Migrating from GPRS to UMTS

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)

Aperture GPRS Support Node (GGSN)

From Global Service for Mobile (GSM) advice radio network, the afterward elements cannot be reused

Abject abject ambassador (BSC)

Abject transceiver abject (BTS)

They can abide in the arrangement and be acclimated in bifold arrangement operation area 2G and 3G networks co-exist while arrangement clearing and new 3G terminals become accessible for use in the network.

The UMTS arrangement introduces new arrangement elements that action as defined by 3GPP:

Node B (base transceiver station)

Radio Arrangement Ambassador (RNC)

Media Aperture (MGW)

The functionality of MSC and SGSN changes if traveling to UMTS. In a GSM arrangement the MSC handles all the ambit switched operations like abutting A- and B-subscriber through the network. SGSN handles all the packet switched operations and transfers all the abstracts in the network. In UMTS the Media aperture (MGW) yield affliction of all abstracts alteration in both ambit and packet switched networks. MSC and SGSN ascendancy MGW operations. The nodes are renamed to MSC-server and GSN-server.

Problems and issues

Some countries, including the United States, accept allocated spectrum abnormally from the ITU recommendations, so that the accepted bands a lot of frequently acclimated for UMTS (UMTS-2100) accept not been available. In those countries, another bands are used, preventing the interoperability of absolute UMTS-2100 equipment, and acute the architecture and accomplish of altered accessories for the use in these markets. As is the case with GSM900 today, accepted UMTS 2100 MHz accessories will not plan in those markets. However, it appears as admitting UMTS is not adversity as abundant from handset bandage affinity issues as GSM did, as abounding UMTS handsets are multi-band in both UMTS and GSM modes. Quad-band GSM (850, 900, 1800, and 1900 MHz bands) and tri-band UMTS (850, 1900, and 2100 MHz bands) handsets are acceptable added commonplace.

The aboriginal canicule of UMTS saw rollout hitches in abounding countries. Overweight handsets with poor array activity were aboriginal to access on a bazaar awful acute to weight and anatomy factor. The Motorola A830, a admission handset on Hutchison's 3 network, advised added than 200 grams and even featured a advertisement camera to abate handset weight. Another cogent affair complex alarm reliability, accompanying to problems with handover from UMTS to GSM. Customers begin their access getting alone as handovers were accessible alone in one administration (UMTS → GSM), with the handset alone alteration aback to UMTS afterwards blind up. In a lot of networks about the apple this is no best an issue.

Compared to GSM, UMTS networks initially appropriate a college abject abject density. For fully-fledged UMTS accumulation video on appeal features, one abject abject bare to be set up every 1–1.5 km (0.62–0.93 mi). This was the case if alone the 2100 MHz bandage was getting used, about with the growing use of lower-frequency bands (such as 850 and 900 MHz) this is no best so. This has led to accretion rollout of the lower-band networks by operators back 2006.

Even with accepted technologies and low-band UMTS, telephony and abstracts over UMTS is still added ability accelerated than on commensurable GSM networks. Apple Inc. cited9 UMTS ability burning as the acumen that the aboriginal bearing iPhone alone accurate EDGE. Their absolution of the iPhone 3G quotes allocution time on UMTS as bisected that accessible if the handset is set to use GSM. Other manufacturers announce altered array lifetime for UMTS approach compared to GSM approach as well. As array and arrangement technology improves, this affair is diminishing.