What is 4G and who defines the terminology?

The International Telecommunications Union (ITU) which is the body responsible for Telecommunications regulation, harmonisation and standardisation creates technology evolution standards. These standards are then applied to create vendor equipment which operators deploy to provide communication services.

This is what they say:

"..IMT-Advanced is considered as “4G”, although it is recognized that this term, while undefined, may also be applied to the forerunners of these technologies, LTE and WiMax...."

   IMT-Advanced is expected to be fully defined by 2012.

So what is WiMAX

Think of your WiFi (home and office wireless network) being able to connect you throughout the city. This is what WiMAX does, give you the same speeds you're able to access on high capacity fixed infrastructure wherever you need it- without the wires!