3G refers to the third generation of mobile telephony (that is, cellular) technology. The third generation, as the name suggests, follows two earlier generations. 3G brings in an era of high internet speed and data transfer in mobile devices. It enhances internet speed that enables us to enjoy myriad features like video calling, faster audio and video streaming, quicker downloads, live TV and a superior social networking experience.
3G provides the additional advantages of data transfer. 3G uses superior software called High Speed Downlink Packet Access (HSDPA), which allows users to send any kind of data, including graphics, audio and video content, many times faster than current 2G networks.
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.
3G technology itself is available in two different forms – WCDMA and HSDPA. While the broader spectrums of 3G benefits are provided by both, they are some subtle differences between them.
W-CDMA or Wideband Code Division Multiple Access is a 3G network interface that allows data connections up to 384 kbps per user (64kbps, 128kbps, 384 kbps) in optimum conditions.
HSDPA or High-Speed Downlink Packet Access on the other hand, is an enhanced 3G interface that enables higher data transfer speeds and capacity. While both are an integral part of 3G technology, the latter provides enhanced speed and capability and is also known as 3.5G.
In otherwords,3G networks are wide area cellular telephone networks which have evolved to incorporate high-speed internet access and video telephony. It offers large capacity and broadband capabilities. It has greater network capacity through improved spectrum efficiency. 3G technology supports around 144 Kbps, with high speed movement, i.e. in a vehicle, 384 Kbps locally, and up to 2Mbps for fixed stations, i.e. in a building. 3G technology uses CDMA, TDMA and FDMA. The data are sent through Packet Switching. Voice calls are interpreted through Circuit Switching. It is a highly sophisticated form of communication that has come up in the last decade.
3G has the following enhancements over 2.5G and previous networks:
· Enhanced audio and video streaming;
· Several Times higher data speed;
· Video-conferencing support;
· Web and WAP browsing at higher speeds;
· IPTV (TV through the Internet) support.
· Global Roaming
There are many 3G technologies as W-CDMA, CDMA2000. UMTS, DECT, WiMAX.
3.5G – HSDPA (High-Speed Downlink Packet Access)
High-Speed Downlink Packet Access (HSDPA) is a mobile telephony protocol, also called 3.5G. It is an enhanced version and the next intermediate generation of 3G UMTS allowing for higher data transfer speeds.
HSDPA is a packet-based data service in W-CDMA downlink with data transmission up to 8-10 Mbps (and 20 Mbps for MIMO systems) over a 5MHz bandwidth in WCDMA downlink. This high data rate is enabled by use of adaptive modulation can coding (AMC), hybrid automatic repeat-request (HARQ), and fast packet scheduling at the access point
3.75G – HSUPA (High-Speed Uplink Packet Access)
High Speed Uplink Packet Access (HSUPA) is a UMTS /WCDMA uplink evolution technology. The HSUPA mobile telecommunications technology is directly related to HSDPA and the two are complimentary to one another.
HSUPA will enhance advanced person-to-person data applications with higher and symmetric data rates, like mobile e-mail and real-time person to person gaming.
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