1) Mobile systems have seen a change of generation, from first to second to third. At the introduction of 1G services, the mobile device was large in size. 1G systems were intended to provide voice service and low rate (about 9.6 kbps) circuit-switched data services. first-generation handsets provided poor voice quality, low talk-time.

2) The 2G systems based on TDMA and CDMA technologies were primarily designed to improve voice quality and provide a set of rich voice features. These systems supported low rate data services.

3) Taking into account the limitations imposed by the finite amount of radio Spectrum available, the focus of the third-generation (3G) mobile systems has been on the economy of network and radio transmission design to provide seamless service.
The third-generation systems provide their users with seamless access to the fixed data network They are perceived as the wireless extension of future fixed networks, as well as an integrated part of the fixed network infrastructure. 3G systems are intended to provide multimedia services including voice, data, and video.