UMTS technology: service the global system of mobile communications: a trading name of the third-generation technology. These criteria have been developed based on technical standards system called GSM sometimes Pal WCDMA
3.5G
HSDPA: download system high-speed packet data: a technique supported by the 3G networks, allowing download Internet data at very high speeds. Ranging theoretical download speed between 1.8 and 7.2 Mbps As well as HSUPA: lifting system High-Speed Data Packet: and is an update for the WCDMA / UMTS / HSDPA where the speed was increased data raise up to speed theory equivalent to 5.8 megabits per second. The system is HSUPA complements the HSDPA system, called the former systems with each name HSPA
4G
4G is still under development and still telecommunications companies use each term 4G on mood, some use it to denote the versions fastest of the HSDPA and the HSUPA and some use it to refer to the WiMax is the development of the system of the Wi-Fi, is characterized by the extent of coverage of a wider range (8 to 30 kilometers). Initial release is designed for WiMax system for securing a wireless communications network for fixed devices (as an alternative to the system home DSL connection). While newer system has been designed to support roaming between feature towers. WiMax depends on broadcast signal on the OFDM technology (communication system with orthogonal frequency). But the International Telecommunications Union launched the 4G label on the LTE protocol (long-term system developer) and which is still under development and it is possible to exceed the speed of the speed of the third generation and a half in the transfer of information up to 14 times The following table shows comparisons between some key parameters of 3G Vs possible 4G systems.
3G
Frequency Band Bandwidth Data rate Access
1.8 - 2.5 GHz 5-20 MHz Up to 2Mbps ( 384 kbps WAN) Wideband CDMA 2 - 8 GHz 5-20 MHz
4G
Up to 20 Mbps or more Multi-carrier - CDMA or