Technical and marketing definitions of 4G
A: There are two definitions for 4G -- a technical definition and a marketing definition.
The technical definition for 4G is that it's a technology that meets the International Telecommunications Union's (ITU's) IMT-Advanced specifications. These specifications include a data rate of 100 Mbps at low mobility pedestrian speed. The technology LTE-Advanced meets these ITU requirements and is therefore 4G.
Many service providers are deploying technologies that offer data rates higher than the initial 3G systems but not high enough to meet the ITU IMT-Advanced requirements. These technologies include WiMAX, HSPA+, and LTE. To distinguish these technologies and help sell the high-speed capabilities, service providers are marketing these services as 4G