4G is an attempt to evolve, integrate and amalgamate the current 2G (2nd Generation), the soon to be released 3G (3rd Generation), broadcast, WLAN functional, seamless Internet work. 4G is NOT a complete overhaul of all old technology. It involves a mix of current concepts and technologies in the making. Some of these are derived from 3G and hence are evolutionary. 4G will feature a scalable, flexible, efficient, autonomous, secure and feature-rich backbone to support a multitude of existing and new converged services (voice data, and multimedia) at data rates of up to 100 Mbps and DoCoMo’s experimental 4G mobile communications system employs variable spreading factor (VSF) and orthogonal frequency code division multiplexing (OFCDM) technologies which is developed by DoCoMo to mitigate the impact of severe multipath interference, and to allow flexible and fast packet transmission in compliance with area and other communications conditions, thereby achieving a broad-bandwidth, large capacity wireless system.