3G is the third generation of mobile data standards designed to meet the new specifications set by the International Telecommunication Union. What this means is that it improved upon the existing second-generation mobile standards. It uses different radio frequencies to 2G and allows for better call quality as well as the first reasonable speeds for Internet access on mobile phones.
2G had been around since the early 90s and was already beginning to show its age. Despite improved version such as 2.5G and 2.75G, a substantial overhaul was needed. As a result, the international telecommunications regulatory and standardisation body set a new range of standards for mobile operators to meet. As it runs in completely different radio frequencies to 2G, some older handsets did not initially supports 3G will stop however, nowadays almost all modern handsets have 3G support.
The minimum specifications to meet 3G standards to peak data rate of at least 200 kbps which equates to about 0.2 Mbps. Compared to 4G this is very fast but as for G should be to provide download speeds of 100 Mpbs you can see that it is much slower.
3G mobile networks are first rolled out in Japan in 1998, but commercial systems only became available in late 2001. The Isle of Man was the first place in Europe to have a fully functioning 3G network. Branding itself after 3G, the mobile network 3 first launched in June 2003. In the early 21st century, other network soon caught up and by June 2007, 200 million mobile users had connected to 3G networks. The European Union Council even suggested that 3G network should cover about 80% of the European national populations by the end of 2005.
Of course, nowadays 3G is widespread but it is set to be completely superseded by 4G in the near future.
For your reference, this is what all the different “types” of 3G refer to:
3G = WCDMA, R99
3.5G = HSDPA
3.75G = HSUPA
3.8G = HSPA+ (HSPA Enhancements)
3.85G = ‘HSPA+’ + MIMO
3.9G = LTE