Wednesday, September 23, 2009


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.

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