The major practical difference between 3G and 4G cellular networks is that 4G networks support much faster data transfer speeds than 3G networks. This increase in speed is due to improvements in cellular hardware and protocols, as well as a switch to pure Internet Protocol telephony in 4G systems.
Both 3G and 4G refer to generations of cellular networking systems, with 3G referring to third-generation systems and 4G to the fourth generation. There are also different versions within 3G and 4G systems themselves, such as the 4G WiMax protocol versus the 4G Long-Term Evolution protocol. However, all implementations of 4G have several advancements over 3G that increase data speeds to as high as 1 gigabit per second over 4G networks.
One of the major technical differences between these two types of networks is the abandonment of classical cellular telephony on 4G networks. 3G networks supported a circuit-switched telephony system that established a dedicated line between a cell phone and the phone it connected to. This is a resource-intensive method of managing phone connections, so 4G adopted a pure IP scheme for phone calls in which phone calls are transmitted using the same kind of packet structure as data over the Internet. In combination with multi-frequency transmission and smart antenna technologies, these changes account for 4G's performance advantage over 3G.