Wireless World
3G (third generation of mobile telephony)
3G refers to the third generation of mobile telephony (that is, cellular) technology. The third generation, as the name suggests, follows two earlier generations.
The
first generation (1G) began in the early 80's with commercial
deployment of Advanced Mobile Phone Service (AMPS) cellular networks.
Early AMPS networks used Frequency Division Multiplexing Access (FDMA)
to carry analog voice over channels in the 800 MHz frequency band.
The
second generation (2G) emerged in the 90's when mobile operators
deployed two competing digital voice standards. In North America, some
operators adopted IS-95, which used Code Division Multiple Access (CDMA)
to multiplex up to 64 calls per channel in the 800 MHz band. Across the
world, many operators adopted the Global System for Mobile
communication (GSM)
standard, which used Time Division Multiple Access (TDMA) to multiplex
up to 8 calls per channel in the 900 and 1800 MHz bands.
The
International Telecommunications Union (ITU) defined the third
generation (3G) of mobile telephony standards IMT-2000 to facilitate
growth, increase bandwidth, and support more diverse applications. For
example, GSM could deliver not only voice, but also circuit-switched
data at speeds up to 14.4 Kbps. But to support mobile multimedia
applications, 3G had to deliver packet-switched data with better
spectral efficiency, at far greater speeds.
However,
to get from 2G to 3G, mobile operators had make "evolutionary" upgrades
to existing networks while simultaneously planning their
"revolutionary" new mobile broadband networks. This lead to the
establishment of two distinct 3G families: 3GPP and 3GPP2.The speed of data transmission on a 3G network ranges between 384KBPS to
2MBPS. This means a 3G network actually allows for more data
transmission and therefore the network enables voice and video calling,
file transmission, internet surfing, online TV, view high definition
videos, play games and much more. 3G is the best option for users who
need to always stay connected to Internet.
Contributor Technologies of 3G
The 3G
technology is comprised of basically three technologies, but it is not
the reason for its nomenclature as 3G. The technologies are:
· CDMA2000 - Code Division Multiple Access.
TD-SCDMA - Time-division Synchronous Code-division Multiple Access.
· W-CDMA (UMTS) - Wideband Code Division Multiple Access.
