The success of second-generation cellphones, especially the Global System for Mobile communications (GSM), motivated the development of a successor system. The need for high speed internet access up to 2 Mbps, high quality videos, images, live video communications, fast web access and the simultaneous data and voice transmission globally led to the development of 3G cellular networks. All these services had to be available in indoor and outdoor environments. The world wide coverage had to be obtained by satellite links. These requirements could not be satisfied by the 2G systems as data rate of only 14.4 Kbps per user was available, which was designed only for speech or low data rate transmissions. In 1998, The International Telecommunication Union (ITU) created a project for a common worldwide cellular standard known as International Mobile Telephony 2000 (IMT 2000) and announced goals for 3G standards. The main requirements were,

• Better spectral efficiency;
• Higher peak data rates - namely, up to 2 Mbit/s indoor and 384 Kbit/s outdoor. This should result in a choice of channels with a bandwidth of 5MHz instead of 200 kHz;
• Supporting multimedia applications, meaning the transmission of voice, arbitrary data, text, pictures, audio and video, which requires increased flexibility in the choice of data rates;
• Backward compatibility to second - generation systems.

IMT 2000 is also referred as Universal Mobile Telecommunication Systems (UMTS) in Europe. Here the number 2000 indicates the start of the system (year 2000), spectrum used (around 2000 MHz region) and also the target user data rates of 2000 kbps (under optimal conditions). This is the global standard for wireless communication connecting the terrestrial and /or satellite based networks. IMT 2000 exploits the digital mobile communication technologies and systems for fixed and mobile wireless communication systems. The aim of 3G is to provide communication services from person to person at any place at any time through any medium using a compact device with guaranteed quality of service and security.