0G
0G, also known as Mobile radio telephone, are the systems that preceded modern cellular mobile telephony technology.
1G
1G (or 1-G) refers to the first generation of wireless telephone technology (mobile telecommunications). These are the analog telecommunications standards that were introduced in the 1980s and continued until being replaced by 2G digital telecommunications. The main difference between the two mobile telephone systems (1G and 2G), is that the radio signals used by 1G networks are analog, while 2G networks are digital.
2G
2G (or 2-G) provide three primary benefits over their predecessors: phone conversations were digitally encrypted; 2G systems were significantly more efficient on the spectrum allowing for far greater mobile phone penetration levels; and 2G introduced data services for mobile, starting with SMS(Short Message Service) plain text-based messages. 2G technologies enabled the various mobile phone networks to provide the services such as text messages, picture messages and MMS (Multimedia Message Service). It has 3 main services : Bearer services is one of them which is also known as data services.
All text messages sent over 2G are digitally encrypted, allowing for the transfer of data in such a way that only the intended receiver can receive and read it.
Second generation 2G cellular telecom networks were commercially launched on the GSM standard in Finland by Radiolinja (now part of Elisa Oyj) in 1991.
3G
3G technology provide an information transfer rate of at least 200 kbit/s. Later 3G releases, often denoted 3.5G and 3.75G, also provide mobile broadband access of several Mbit/s to smartphones and mobile modems in laptop computers. This ensures it can be applied to wireless voice telephony, mobile Internet access, fixed wireless Internet access, video calls and mobile TV technologies.
A new generation of cellular standards has appeared approximately every tenth year since 1G systems were introduced in 1981/1982. Each generation is characterized by new frequency bands, higher data rates and non–backward-compatible transmission technology. The first 3G networks were introduced in 1998 and fourth generation 4G networks in 2008.
3.5G
3.5G is a grouping of disparate mobile telephony and data technologies designed to provide better performance than 3G systems, as an interim step towards deployment of full 4G capability. The technology includes:
4G
4G provides, in addition to the usual voice and other services of 3G, mobile broadband Internet access, for example to laptops with wireless modems, to smartphones, and to other mobile devices. Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television, and cloud computing.
4.5G
4.5G provides better performance than 4G systems, as an interim step towards deployment of full 5G capability. The technology includes:
5G
5G denotes the next major phase of mobile telecommunications standards beyond the current 4G/IMT-Advanced standards.
NGMN Alliance or Next Generation Mobile Networks Alliance define 5G network requirements as:
Next Generation Mobile Networks Alliance feel that 5G should be rolled out by 2020 to meet business and consumer demands. In addition to simply providing faster speeds, they predict that 5G networks will also need to meet the needs of new use-cases such as the Internet of Things as well as broadcast-like services and lifeline communications in times of disaster.