What is 4G?
4G (or 4-G) is short for fourth-generation the successor of 3G and is a wireless access technology. It describes two different but overlapping ideas. The IEEE (Institute of Electrical and Electronics Engineers) official name for 4G is “3G and beyond”.
4G technology stands to be the future standard of wireless devices.
In general, a generation is defined by the result of technology changes over a 10-15 year time frame. Thus, 4G would refer to whatever is deployed in the 2010-2015 period, assuming 3G deployment spans the 2000-2009 period. Typically, this means a new air-interface with higher data rates in the least, and some see change in the way data transport is handled end-to-end.
Ideally, 4G would provide users with on demand high quality video and audio. The killer application of 4G is not clear, but video is one of the big differences between 4G and 3G. 4G may use OFDM (Orthogonal Frequency Division Multiplexing), and also OFDMA (Orthogonal Frequency Division Multiple Access) to better allocate network resources to multiple users. 4G devices may use SDR (Software-defined radio) receivers which allows for better use of available bandwidth as well as making use of multiple channels simultaneously.
Unlike the 3G networks which are a jumble of circuit switched and packet switched networks, 4G will be based on packet switching only. This will allow low-latency data transmission.
Source: Wikipedia
