The Universal Mobile Telecommunication System (UMTS) is the third generation mobile communications system being developed within the IMT -2000 framework. UMTS will build on and extend the capability of today's mobile technologies (like digital cellular and cordless) by providing increased capacity, data capability and a far greater range of services. In January 1998, ETSI reached an agreement concerning the radio access technique to be used for UMTS. This air interface, named UTRAN (UMTS Terrestrial Radio Access) is applicable in the two existent duplexing schemes for UMTS: UMTS-FDD and UMTS- TTD. UMTS-FDD relies on wideband-CDMA (W-CDMA) access technique, while UMTS- TTD uses the TD-CDMA access technique, a combination of CDMA and TDMA technologies.
Bluetooth operates in the unlicensed 2.4--GHz ISM (industrial, scientific and medical) band and uses a frequency- hopping spread spectrum (FHSS) technique to minimise interference. A Bluetooth unit has a nominal range of approximately 10 meters (in the Class 3 defined in the standard, but which can be enlarged by amplifying the transmit power in Class 2 and Class 1 up to 100 m.). Two or more Bluetooth units sharing the same channel form a piconet. Each piconet consists of a master unit and up to seven active slave units. Furthermore, two or more piconets can be interconnected to form a scattemet. To be a part of more than one piconet a unit called inter-piconet unit (gateway) is required.
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