Tuesday, August 25, 2009

3G history

First generation wireless, or 1G, refers to analogue networks introduced in the mid-1980s.
Examples include advanced mobile phone service (AMPS) used in North America and total access
communications system (TACS) used in the UK. In South Africa we had the C450 mobile system
run by Telkom which was relatively expensive and took ten years to achieve ten thousand subscribers. Most 1G technologies and systems were country or region-specifi c and thus offered
limited coverage.As mobile communications grew in popularity, networks often became
overloaded, resulting in busy signals and dropped calls. The solution was second-generation
wireless, or 2G, which emerged in the early 1990s. 2G technologies were digital and offered
the much-needed capacity that 1G analogue systems did not afford. Several technologies were
widely used:


• GSM was and still is popular in Europe and Asia Pacifi c, and Latin America
• TDMA was used in the Americas and is still used in Latin America
• CDMA IS-95 or cdmaOne was used primarily in the Americas and Asia Pacific

However, these 2G technologies are incompatible with each other. Thus, mobile service subscribers were still often limited to using their phones in a single country or region. In an effort to standardise future digital wireless communications and make global roaming with a single handset possible, the ITU established a single standard for wireless networks in 1999. Called IMT-2000, which is commonly referred to today as 3G, the initiative set forth the requirements (mentioned above) for the third generation of wireless networks.

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