Mobile phones have become an indispensable part of the modern lifestyle. Today mobile phones can store personal information, surf the Internet, send/receive photos, play music, shoot videos, and have host of other features above and over making a call. Integration with GPS allows for location based services (LBS) also. A lot of the features like SMS, MMS, WAP, are now taken for granted, and the future promises many more interactive and media-rich applications.
You will be bombarded by a huge number of topics, if you try to uncover the number of technologies and their variants in the cellular scene. In the market, the Global System for Mobile (GSM) boasts the greatest share of users, with over 900 million subscribers worldwide. GSM uses TDMA to assign users with channels. GSM networks uses GPRS to provide packet data (e.g. Internet access) services and EDGE to increase data rates. Other technologies like cdmaOne and CDMA2000 which use CDMA as their channel access technique also have a promising future.
The first generation of the mobile and cellular technology were the analogue standards like AMPS and ETACS. The second generation of standards used digital modulation techniques. Example of 2G standards are GSM, IS-136 TDMA, CDMA, etc. Intermediate standards were called 2.5G (e.g. GPRS) and 2.75G (e.g. EDGE), to show increase in data rates.
The third generation of mobile technologies are converging to two standards: UMTS and UWC-136. The UMTS standard is the evolutionary step for the current GSM/GPRS and CDMA standards. UMTS uses Wideband CDMA (WCDMA) for its air interface. UWC-136 is the 3G evolutionary step for IS-136 TDMA networks and as the name suggests uses TDMA for channel access.
The fourth generation (4G) promises even higher data rates and breath-taking applications. 4G applications include full colour video streaming and conferencing, and virtual presence. The future is worth waiting for!!!

[GSM ]  [ SMS ]  [ GPRS ]  [ CDMA ]  [ CDMA 2000 ]  [ WCDMA ]