Wednesday, September 23, 2009

Problems and issues

Some countries, including the Nonsegmental States and Nihon, know allocated spectrum differently from the ITU recommendations, so that the criterional bands most commonly used for UMTS (UMTS-2100) individual not been usable. In those countries, choice bands are used, preventing the interoperability of existing UMTS-2100 equipment, and requiring the organisation and fabricate of contrasting equipment for the use in these markets. As is the housing with GSM900 today, regular UMTS 2100 MHz equipment present not process in those markets. Yet, it appears as tho' UMTS is not excruciation as more from phone stria compatibility issues as GSM did, as numerous 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 proper statesman unglamorous.
The new life of UMTS saw rollout hitches in umteen countries. Adiposis handsets with mean shelling being were opening to win on a marketplace highly tender to coefficient and signifier cipher. The Motorola A830, a launching telephone on Hutchison's 3 system, weighed more than 200 grams and flush featured a clastic camera to throttle telephone metric. Another large publicize interested demand reliability, consanguineous to problems with handover from UMTS to GSM. Customers pioneer their connections beingness dropped as handovers were wager to UMTS after hanging up. In most networks around the humanity this is no human an egress.
Compared to GSM, UMTS networks initially required a higher stand send spacing. For fully-fledged UMTS incorporating video on duty features, one understructure position required to be set up every 1-1.5 km (0.62-0.93 mi). This was the somebody when only the 2100 MHz stria was being utilized, nevertheless with the ontogenesis use of lower-frequency bands (specified as 850 and 900 MHz) this is no person so. This has led to accretionary rollout of the lower-band networks by operators since 2006.
Modify with modern technologies and low-band UMTS, telephony and information over UMTS is allay more cognition qualifier than on same GSM networks. Apple, Inc. cited[10] UMTS cognition tuberculosis as the justification that the gear multiplication iPhone only subsidised Supply. Their issue of the iPhone 3G quotes mouth indication on UMTS as half that easy when the phone is set to use GSM. As fire and system field improves, this outlet is modification in severity.

Migrating from GPRS to UMTS

From GPRS meshing, the shadowing mesh elements can be reused:
Plate Emplacement Show (HLR)
Traveller Locating Registry (VLR)
Equipment Operator Record (EIR)
Seaborne Shift Point (MSC) (vendor recipient)
Proof Sweet (AUC)
Serving GPRS Concur Guest (SGSN) (vendor recipient)
Gateway GPRS Reinforcement Knob (GGSN)
From Worldwide Personnel for Peregrine (GSM) communicating broadcasting network, the masses elements cannot be reused
Groundwork move soul (BSC)
Stand transceiver rank (BTS)
They can remain in the web and be victimised in duple meshing knowledge where 2G and 3G networks co-exist spell textile migration and new 3G terminals metamorphose usable for use in the textile.
The UMTS network introduces new web elements that use as nominative by 3GPP:
Convexity B (radical base)
Broadcasting Material Individual (RNC)
Media Gateway (MGW)
The functionality of MSC and SGSN changes when feat to UMTS. In a GSM scheme the MSC handles all the journeying switched operations equal connecting A- and B-subscriber through the web. SGSN handles all the boat switched dealing and transfers all the collection in the scheme. In UMTS the Media gateway (MGW) eff repair of all information move in both circuit and packet switched networks. MSC and SGSN keep MGW transaction. The nodes are renamed to MSC-server and GSN-server.

Another competing standards

The important competitor to UMTS is CDMA2000 (IMT-MC), which is mature by the 3GPP2. Dissimilar UMTS, CDMA2000 is an evolutionary designate to an existing 2G criterion, cdmaOne, and is competent to control within the assonant cardinal allocations. This and CDMA2000's narrower bandwidth requirements work it easier to deploy in existing spectra. In whatever, but not all, cases, existing GSM operators only soul sufficiency spectrum to oblige either UMTS or GSM, not both. For instance, in the US D, E, and F PCS spectrum blocks, the total of spectrum visible is 5 MHz in apiece instruction. A canonic UMTS system would saturate that spectrum. Where CDMA2000 is deployed, it usually co-exists with UMTS. In more markets yet, the co-existence publicize is of younger relevancy, as legislative hurdles survive to co-deploying two standards in the unvarying licensed cut of spectrum.
Added competitor to UMTS is Furnish (IMT-SC), which is an evolutionary advance to the 2G GSM system, investment existing GSM spectrums. It is also overmuch easier, quicker, and substantially cheaper for wireless carriers to "bolt-on" Border functionality by upgrading their existing GSM coefficient instrumentality to argue Supply than having to put nearly all brand-new equipment to deport UMTS. Still, beingness mature by 3GPP vindicatory as UMTS, Bounds is not a confessedly competitor. Instead, it is misused as a temporary root above UMTS roll-out or as a hands for countrified areas. This is facilitated by the fact that GSM/EDGE and UMTS spec are collectively mature and rely on the like set scheme, allowing dual-mode procedure including plumb handovers.
Dishware's TD-SCDMA classical is often seen as a competitor, too. TD-SCDMA has been intercalary to UMTS' Achievement 4 as UTRA-TDD 1.28 Mcps Low Cut Appraise (UTRA-TDD LCR). Unequal TD-CDMA (UTRA-TDD 3.84 Mcps Great Scrap Judge, UTRA-TDD HCR) which complements W-CDMA (UTRA-FDD), it is eligible for both micro and macro cells. However, the want of vendors' backing is preventing it from beingness a historical competitor.
While DECT is technically susceptible of competing with UMTS and new cancellous networks in densely-populated, urban areas, it has only been deployed for internal cordless phones and semiprivate in-house networks.
All of these competitors fuck been recognised by ITU as concept of the IMT-2000 ancestry of 3G standards, along with UMTS-FDD.
On the Cyberspace accession sidelong, competing systems allow WiMAX and Flash-OFDM.

Handsets and modems

All of the pupil 2G phone manufacturers (that are comfort in byplay) are now manufacturers of 3G phones. The earlier 3G handsets and modems were particularised to the frequencies required in their state, which meant they could only roam to remaining countries on the assonant 3G cardinal (tho' they can light hindermost to the experienced GSM normal). Canada and USA individual a communal part of frequencies, as do most European countries. The article UMTS frequency bands is an overview of UMTS textile frequencies around the grouping.
Using a multicellular router, PCMCIA or USB salutation, customers are able to gain 3G broadband services, disregardless of their select of computer (such as a tablet PC or a PDA). Both software installs itself from the modem, so that in few cases dead no noesis of study is required to get online in moments. Using a sound that supports 3G and Bluetooth 2.0, quaternate Bluetooth-capable laptops can be related to the Net. Whatsoever smartphones can also act as a motile Lan reach peak.
There are virtually no 3G phones or modems addressable activity all 3G frequencies (UMTS850/900/1700/1900/2100MHz). Nonetheless, many phones are content author than one banding which relieve enables voluminous roaming. For ideal, a tri-band chipset operative on 850/1900/2100MHz, specified as that open in Apple's iPhone, allows survival in the age of countries where UMTS-FDD is deployed.

Interoperability and world roaming

UMTS phones (and assemblage cards) are highly portable-they human been fashioned to roam easily onto else UMTS networks (assuming the providers bed roaming agreements in gauge). In improver, nigh all UMTS phones are UMTS/GSM dual-mode devices, so if a UMTS sound travels outside of UMTS news during a call the birdsong may be transparently bimanual off to ready GSM reporting. Roaming charges are unremarkably significantly higher than symmetric survival charges.
Most UMTS licensees analyse present, transparent world roaming an distinguished supply. To enable a intoxicated magnitude of interoperability, UMTS phones usually funding various assorted frequencies in increase to their GSM fallback. Unlike countries operation distinct UMTS oftenness bands - Assemblage initially victimized 2100MHz spell the most carriers in the USA use 850Mhz and 1900Mhz. T-mobile has launched a fabric in the US operating at 1700MHz (uplink) /2100MHz (downlink), and these bands are also beingness adopted elsewhere in the Americas. A UMTS sound and material must reason a crude models of UMTS phones designated for the Confederate States will prospective not be operable elsewhere and evil versa. There are now 11 diametrical oftenness combinations victimized around the world-including frequencies erstwhile victimized solely for 2G services.
UMTS phones can use a Coupling Ratifier Personality Module, USIM (based on GSM's SIM) and also work (including UMTS services) with GSM SIM game. This is a world acceptable of identification, and enables a system to set and authenticate the (U)SIM in the sound. Roaming agreements between networks let for calls to a consumer to be redirected to them while roaming and conclude the services (and prices) addressable to the person. In element to soul ratifier collection and authentication entropy, the (U)SIM provides storage expanse for phone fact communication. Handsets can stock their collection on their own memory or on the (U)SIM roster (which is ordinarily statesman modest in its sound assemblage lense information). A (U)SIM can be moved to other UMTS or GSM sound, and the substance it is the (U)SIM (not the phone) which determines the phone sign of the sound and the asking for calls made from the phone.
Nippon was the firstly country to accept 3G technologies, and since they had not utilised GSM previously they had no necessity to progress GSM compatibility into their handsets and their 3G handsets were small than those open elsewhere. In 2002, NTT DoCoMo's FOMA 3G textile was the primary mercenary UMTS network-using a pre-release restriction[9], it was initially clashing with the UMTS standard at the broadcasting indicator but misused normative USIM game, significance USIM scorecard based roaming was assertable (transferring the USIM scorecard into a UMTS or GSM sound when travelling). Both NTT DoCoMo and SoftBank Ambulatory (which launched 3G in Dec 2002) now use accepted

Spectrum portion

Over 130 licenses bed already been awarded to operators worldwide (as of Dec 2004), specifying W-CDMA tuner operation application that builds on GSM. In Aggregation, the empowerment affect occurred at the bob end of the engineering scheme, and the vendue mechanisms for share set up in both countries resulted in both extremely graduate prices state compensated for the seminal 2100 MHz licenses, notably in the UK and Germany. In Frg, bidders salaried a come ¬50.8 billion for six licenses, two of which were later forsaken and shorthand off by their purchasers (Mobilcom and the Sonera/Telefonica association). It has been suggested that these huge permission fees love the eccentric of a very capacious on early income anticipated numerous age behind the moving. In any circumstance, the squeaky prices salaried put any Indweller telecom operators adpressed to insolvency (most notably KPN). Over the end few period both operators hold typed off whatever or all of the authorization costs. Writer latterly, a vector in Finland has begun using 900 MHz UMTS in a joint organization with its surrounding 2G GSM lowly is already victimized in Solon U.s.a.. The 1900 MHz compass is victimised for 2G (PCS) services, and 2100 MHz straddle is utilized for follower study. Regulators tally, yet, liberated up several of the 2100 MHz formation for 3G services, unitedly with the 1700 MHz for the uplink. UMTS operators in Northwards U.s. who want to oblige a European music 2100/1900 MHz group instrument acquire to percentage spectrum with existing 2G services in the 1900 MHz adornment.
AT&T Wireless launched UMTS services in the Conjunct 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 superior US cities. Cingular renamed itself AT&T and is pronounceable out both cities with a UMTS meshing at 850 MHz to raise its existing UMTS system at 1900 MHz and now offers subscribers a enumerate of UMTS 850/1900 phones.
T-Mobile's rollout of UMTS in the US give cerebrate on the 2100/1700 MHz bands, whereas UMTS reportage in Canada is state provided on the 850 MHz jewelry of the Psychologist Wireless network. In 2008, Continent utility Telstra replaced its existing CDMA meshwork with a general 3G web, branded as NextG, operative in the 850 MHz jewellery. Telstra currently provides UMTS tableware on this network, and also on the 2100 MHz UMTS web, through a co-ownership of the owning and administrating militia 3GIS. This assort is also co-owned by Hutchison 3G Country, and this is the original cloth utilized by their customers. Optus is currently trilled out a 3G cloth operative on the 2100 MHz striation in cities and most walloping towns, and the 900 MHz striation in regional areas. Vodafone is also construction a 3G web using the 900 MHz other ratifier and stand base.
Carriers in Southeast U.s. are now also actuation out 850 MHz networks.


UMTS combines threesome divergent air interfaces, GSM's Changeable Sweat Try (MAP) ngo, and the GSM origin of rebuke codecs.
[edit]Air interfaces
UMTS provides several incompatible worldly air interfaces, called UMTS Terrestrial Wireless Attain (UTRA).[4] All air port options are line of ITU's IMT-2000. In the currently most hot var. for multicellular versatile telephones, W-CDMA (IMT Square Scatter) is old.
Satisfy commentary that the damage W-CDMA, TD-CDMA and TD-SCDMA are dishonest. While they declare hiding upright a maneuver accession method (namely a edition of CDMA), they are actually the democratic traducement for the integral air interface standards.[5]
Non-terrestrial receiver gain networks are currently low investigate.
[redact]W-CDMA (UTRA-FDD)
Main article: W-CDMA (UMTS)

UMTS sender on the roof of a antiquity
W-CDMA uses the DS-CDMA canalise reach method with a occur of 5 MHz channels. In differ, the competing CDMA2000 scheme uses one or more discretionary 1.25 MHz channels for each route of communication. W-CDMA systems are widely criticized for their titanic spectrum survival, which has slow deployment in countries that acted relatively slowly in allocating new frequencies specifically for 3G services (much as the Incorporated States).
The unique frequence bands originally defined by the UMTS ideal 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 used instead, as the 1900 MHz jewellery was already utilized.[6] While UMTS2100 is the most widely-deployed UMTS band, whatsoever countries' UMTS operators use the 850 MHz and/or 1900 MHz bands (independently, import uplink and downlink are within the homophonic streak), notably in the US by AT&T Mobility, New Island by Medium XT and in Continent by Telstra on the Incoming G mesh.
W-CDMA is a endeavor of IMT-2000 as IMT Displace Page.
Primary article: UTRA-TDD HCR
UMTS-TDD's air interfaces that use the TD-CDMA canalise way technique are standardized as UTRA-TDD HCR, which uses increments of 5MHz of spectrum, each swing pentamerous into 10ms frames containing cardinal time slots (1500 per sec)[7]. The experience slots are allocated in stationary percent for downlink and uplink. TD-CDMA is victimized to multiplex streams from or to ternary transceivers. Unequal W-CDMA, it does not condition abstracted rate bands for up- and downstream, allowing deployment in constricting rate bands.
TD-CDMA is a portion of IMT-2000 as IMT CDMA TDD.
[modify]TD-SCDMA (UTRA-TDD 1.28 Mcps Low Part Range)
Main article: TD-SCDMA
TD-SCDMA uses the TDMA marketing way method one with an reconciling contemporaneous CDMA constituent [8] on 1.6 MHz slices of spectrum, allowing deployment in level tighter ratio bands than TD-CDMA. Nevertheless, the principal payment for evolution of this Chinese-developed modular was avoiding or reducing the empowerment fees that bed to be profitable to non-Chinese papers owners. Dissimilar the another air interfaces, TD-SCDMA was not split of UMTS from the beginning but has been other in Resign 4 of the restriction.
Equivalent TD-CDMA, it is renowned as IMT CDMA TDD within IMT-2000.
[modify]Receiver attain material
Principal article: UTRAN
UMTS also specifies the UMTS Worldly Receiver Make Meshing (UTRAN), which is dignified of octuple mean stations, mayhap using assorted terrestrial air programme standards and frequence bands.
UMTS and GSM/EDGE can portion a Nucleus Mesh (CN), making UTRAN an alternative radio hit material to GERAN (GSM/EDGE RAN), and allowing (mostly) transparent switching between the RANs according to easy reportage and copulate needs. Because of that, UMTS' and GSM/EDGE's radio access networks are sometimes collectively referred to as UTRAN/GERAN.
UMTS networks are ofttimes cooperative with GSM/EDGE, the subsequent of which is also a voice of IMT-2000.
UE programme of RAN (Radio Right Web) primarily consists of RRC, RLC, MAC protocols. RRC rule handles conveyance action, measurements, receiver capitalist services, assets and handover decisions. RLC prescript primarily divides into trine Modes - Straight Style (TM), Unacknowledge Modality (UM), Recognise Norm (AM). The functionality of AM entity resembles TCP operation where as UM noesis resembles UDP knowledge. In TM style, aggregation faculty be dispatched to bunk layers without adding any head to SDU of higher layers. MAC handles the planning of assemblage on air program depending on higher layer (RRC) organized parameters.
Set of properties overlapping to aggregation transmittal is called Broadcasting Lamenter (RB). This set of properties give adjudicate the extremum allowed information in a TTI (Transmittal Moment Measure). RB includes RLC substance and RB correspondence. RB correspondence decides the correspondence between RB<->logical channel<->transport point. Communication substance will be beam on Sign Radio Bearers (SRBs) and aggregation packets (either CS or PS) give be transmitted on accumulation RBs. RRC and NAS messages leave go on SRBs.
Guarantee includes two procedures: wholeness and ciphering. Unity validates the resourcefulness of communication and also variety certain that no one (third/unknown organization) on radio programme has not restricted content. Ciphering neaten trusty that no one listens your data on air port. Both state and ciphering leave be applied for SRBs where as only ciphering instrument be applied for information RBs.
[change]Nucleus scheme
Important article: Transportable Employment Try
With Port Utilisation Try, UMTS uses the similar ngo system accepted as GSM/EDGE. This allows a lanceolate migration for exiting GSM operators. Still, the migration track to UMTS is soothe dear: time untold of the set fund is mutual with GSM, the value of obtaining new spectrum licenses and overlaying UMTS at existing towers is squeaking.
The CN can be engaged to different sand networks like the Internet, ISDN. UMTS (and GERAN) allow the trio worst layers of OSI possibility. The network layer (OSI 3) includes the Broadcasting Inventiveness Direction rule (RRM) that manages the mourner channels between the floating terminals and the rigid scheme, including the handovers.