27-07-2011, 04:42 PM
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Introduction:
A mobile phone is an electronic device used for two-way radio telecommunication
In telephony, 4G is the fourth generation of cellular wireless standards. It is a successor to 3G and 2G families of standards.
The existing 3G W-CDMA standard will be replaced in 4G by VSF-OFCDM and VSF-CDMA.
The 4G adoption of concatenated FEC (Forward Error Correction) will allows larger data packets to be transmitted and reduces the bit error rate.
Zero Generation Mobile Systems (0G) :
The radio telephone system preceded modern cellular mobile telephony technology (1G).
The radio telephone system contained one central antenna tower per region. The central antenna required radio phones to have a powerful transmitter, capable of transmitting up to 50 miles. The number of radio telephones per region was limited by the number of available channels.
Unlike closed radio systems, radio telephones were connected to the public telephone network and were typically mounted in cars, trucks, and briefcases.
First Generation Cellular Communication (1G):
The 1G cellular telephone system divided cities into small cells. This division allowed extensive frequency reuse across a city, allowing millions to use cell phones simultaneously.
1G (or 1-G) refers to the first-generation of wireless telephone technology.
These are the analog telecommunications standards that were introduced in the 1980s1G cell phone technology encompassed analog standards introduced in the 1980s and continued until replaced by 2G digital cell phones.
Second Generation Cellular Communication (2G):
By the end of the year 1980 the digital telecommunication standards were developed.
These systems provided better voice quality with higher capacity which even costed low.
2G digital technologies can be divided into two standards: TDMA (Time Division Multiple Access) - GSM: Originally from Europe but used worldwide - iDEN: Proprietary network used by Nextel in the US - PDC: Used exclusively in Japan CDMA (Code Division Multiple Access) - IS-95: Commonly referred to as CDMA and used in the Americas and parts
Third Generation Cellular Communication (3G):
3G networks provide the ability to transfer voice data and non-voice data (music downloads, emails and instant messaging) over the same network simultaneously.
IMT-2000 is better known as 3G
3G provide faster communication services which include: voice ,fax internet. Broadband capabilities to support greater numbers of voice and video calls.
3G networks deliver broadband capacity and support greater numbers of voice and data customers at lower incremental costs than 2G.
Standards: - W-CDMA: Wideband Code Division Multiple Access - EVDO: Evolution-Data Optimized