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Posted by crouse
www.ITBusinessEdge.com
Posted by crouse
2G data band widith is small compared to 3G is band widith is
2G=64kbsp
3G=364kbps and more
Posted by satpal
2G networks (GSM, cdmaOne, DAMPS) are the first digital cellular systems launched early 1990s
The existing mobile phone market is referred to as the "second generation" of digital mobile communications, or "2G" (analogue mobile phones were "1G"). The European market is controlled by the Global System for Mobile communications (GSM) digital wireless standard. This uses TDMA as its radio transmission technology (RTT) (see the section on 3G Technology for a description of TDMA). GSM has proven to be the great success story of mobile standards as it has become the unifying standard in Europe - it is possible to use one phone throughout Western Europe. Because of the number of wireless users are in Europe this has greatly strengthened GSM's position as the basis for a potential global standard. The hegemony of GSM has resulted in Finland's Nokia and the UK's Vodafone becoming the powerhouses of the wireless economy.
In North America the situation is not nearly so unified. The situation is divided three-ways between GSM, a TDMA-based system from AT&T Wireless (IS-136), and a CDMA system called CDMAone (IS-95A) from Sprint and Verizon. This confusion of standards has resulted in the reduced popularity of cellphones in the US. CDMAone has perhaps the strongest grip on the American market, as well as being popular in Asia.
3G networks (UMTS FDD and TDD, cdma2000 1x EVDO, cdma2000 3x, TD-SCDMA, Arib WCDMA, EDGE, IMT-2000 DECT) are the latest cellular networks that have data rates 384kbit/s and more.
The dream of 3G is to unify the world's mobile computing devices through a single, worldwide radio transmission standard. Imagine being able to go anywhere in the world secure in the knowledge that your mobile phone is compatible with the local system, a scenario known as "global roaming". Unfortunately, the process of unifying the numerous international standards has proved to be extremely difficult. After difficult negotiation, a 3G "standard" called IMT-2000 emerged as a rather unsatisfactory compromise. IMT-2000, in fact, represents several incompatible standards lumped together under one banner. The hope of IMT-2000 is that phones using these different standards will be able to move seamlessly between all networks, thus providing global roaming.
The rather fragmented nature of IMT-2000 has resulted in a proliferation of confusion acronyms (e.g., TDMA, UMTS, EDGE) often referred to as "alphabet soup". Possibly the most important acronym to remember is "UMTS": this is the 3G standard for Europe and Japan.
UMTS is the successor to the current ultra-successful GSM mobile phone standard in Europe. UMTS is being very heavily sold as the 3G standard (some sources use the terms "3G" and "UMTS" synonymously, though this is really not correct and just adds to the confusion).
The main global competitor to UMTS is CDMA2000, the 3G standard developed in the U.S. by Qualcomm. UMTS and CDMA2000 look set to battle it out for global supremacy. However, other less-publicised standards will not let those two have it all their own way. It is hoped that the following guide will act as a roadmap through the confusing subject of 3G standards. Let's start by stepping back a "G"...
Also refer this link http://www.three-g.net/3g_standards.html for more details
Posted by shaw
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