Generations in mobile communication

1G:

The first generation of systems for mobile telephony was analog, circuit switched, and it only carried voice traffic. The analog phones used in 1G were less secure and prone to interference where the signal is weak. Analog systems include AMPS, NMT and ETACS.

2G:

The second-generation phones cover all speech into digital code, resulting in a clear signal that can be encrypted for security. Most also include some kind of messaging, as well as support for Centrex style services such as voice mail and caller ID. 

The most popular is GSM (Global System for Mobile Communications), but several others are used around the world. They can send data, but usually at less than 10 kilobits per second (Kbps); by comparisons, most modems achieve a real speed of atleast 30 Kbps. 

2G networks include GSM, D-AMPS (TDMA) and CDMA. 2G networks can support SMS applications.


2.5 G:

The successor of the 2G technology is the 2.5G. 2.5 G supports higher data speeds. The term 2.5G also applies to technology such as WAP (Wireless Application Protocol), which uses a version of the web to fit into a mobile phone’s slow data rate and small screen. 

2.5G networks include EDGE (Enhanced Data Rates) and GPRS (General Packet Radio Service). These networks support WAP, MMS, SMS mobile games, and search and directory. Though MMS was introduced in the 2.5G, it really gained its momentum and fame only with the introduction of 3G.

3G:

As the use of 2G phones became more widespread and people began to utilize mobile phones in their daily lives, it became clear that demand for data services (such as access to the internet) was growing. Furthermore, experience from fixed broadband services showed there would also be an ever increasing demand for greater data speeds. The 2G technology was nowhere near up to the job, so the industry began to work on the next generation of technology known as 3G. 

The main technological difference that distinguishes 3G technology from 2G technology is the use of packet switching rather than circuit switching for data transmission.

4G

By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by the growth of bandwidth-intensive applications like streaming media. Consequently, the industry began looking to data-optimized 4th-generation technologies, with the promise of speed improvements up to 10-fold over existing 3G technologies. 

The first two commercially available technologies billed as 4G were the WiMAX standard and the LTE standard.

5G is not officially used for any specification or official document yet made public by telecommunication companies or standardization bodies such as 3GPP, WiMAX Forum, or ITU-R.

          

Comparison of different Generations.