What is spectrum?
Radio spectrum refers to a range of radio frequencies. The bandwidth of a radio signal is the difference between the upper and lower frequencies of the signal.
For example, in the case of a voice signal having a minimum frequency of 200 hertz (Hz) and a maximum frequency of 3,000 Hz, the bandwidth is 2,800 Hz (3 KHz). The amount of bandwidth needed for 3G services could be as much as 15-20 Mhz, whereas for 2G services a bandwidth of 30-200 KHz is used. Hence, for 3G huge bandwidth is required.
How is 3G different from 2G and 4G?
While 2G stands for second-generation wireless telephone technology, 1G networks used are analog, 2G networks are digital and 3G (third-generation) technology is used to enhance mobile phone standards.
3G helps to simultaneously transfer both voice data (a telephone call) and non-voice data (such as downloading information, exchanging e-mail, and instant messaging. The highlight of 3G is video telephony. 4G technology stands to be the future standard of wireless devices.
Currently, Japanese company NTT DoCoMo and Samsung are testing 4G communication.
In how many countries does 3G exist?
There are about 60 3G networks across 25 countries . In Asia, Europe and the USA, telecom firms use WCDMA technology. The WCDMA standard provides seamless global evolution from today's GSM with support of the worlds' largest mobile operators.
WCDMA technology is built on open standards, wide ranging mobile multimedia possibility, and vast potential economies of scale with the support of around 100 terminal designs to operate 3G mobile networks.
3G services were introduced in Europe in 2003.
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