lunes, 31 de mayo de 2010

UMTS Features.

  • Supports maximum theoretical data transfer rates of 21 Mbit/s (with HSDPA),[3] although at the moment users in deployed networks can expect a transfer rate of up to 384 kbit/s for R99 handsets, and 7.2 Mbit/s for HSDPA handsets in the downlink connection. UMTS has the ability to provide data rates upto 2 Mbps. This is maximum if we compare it with other 2G and 2.5G networks. This would in turn bring features such as video conferencing, real time streaming and other high bandwidth applications into reality. Furthermore, Bearer services have different QoS (Quality Of Service) parameters for maximum transfer delay, delay variation and bit error rate. Offered data rates could be 144 kbps for setallite/rural outdoor, 384 kbps for urban outdoor, 2048 kbps for indoor and low range outdoor.
  • Air interfaces: UMTS provides several different terrestrial air interfaces, called UMTS Terrestrial Radio Access (UTRA). All air interface options are part of ITU's IMT-2000. In the currently most popular variant for cellular mobile telephones, W-CDMA (IMT Direct Spread) is used.
  • Please note that the terms W-CDMA, TD-CDMA and TD-SCDMA are misleading. While they suggest covering just a channel access method (namely a variant of CDMA), they are actually the common names for the whole air interface standards. Non-terrestrial radio access networks are currently under research.
  • Current cellular systems are based upon circuit-switched data while UMTS is based on packet switching technolody. This would bring highly customized and controlled data rates while being virtually connected all the times. This will also allow to have several forms of billing such as pay per download, pay per session etc depending upon the requirement of the service used.
  • UMTS is also providing "data rate on demand" feature which could make the charges more cheap.
  • UMTS is perceived as a global system of communication. Hence, it is also providing compatibility with other networks such as GSM and Satellite. Satellite is the major way to provide global access, hence UMTS has been standardised to ensure an efficient and effective roaming and handover between satellite and terrestrial networks. UMTS will also provide consistent set of services while a user switches from one network to another during roaming. This terminology is also reffered to as VHE (Virtual Home Environment).

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