Fourth Generation (4G) mobile technology is a set of standards for providing broadband Internet access to devices like cellphones and tablets. Though it first became available in the US in 2009, no specific technologies were officially designated as 4G until 2011. Despite this, many devices were labeled as "4G" even though they did not meet the International Telecommunication Union's (ITU) standards for the technology. The main difference between it and previous standards is a big increase in data transfer speeds and the types of media people can access with it.
There are also a number of technical specifications, including things like the wireless standard, radio interface, and frequency spectrum used. As of 2011, there were only two technologies officially designated as 4G mobile: LTE-Advanced and WiMax Release 2. Though devices using these technologies can theoretically reach the data speeds and functionality requirements set out by the ITU, the actual function varies according to the network coverage, infrastructure, and location.
Former versions of LTE and WiMax, and another technology called HSPA+, are also commonly referred to as 4G; despite the name, none actually meet the standards set out in IMT-A. The technologies were marketed so often as "4G" that the ITU allowed them to claim the designation. Most major carriers in the US work with at least one of these standards, with some supporting both. Generally speaking, LTE services are faster than WiMax, but WiMax can often support a farther-ranging signal than LTE, meaning that a user could conceivably use the mobile device farther away from a hotspot. Additionally, LTE is primarily used for cellphones and similar mobile devices, while WiMax is sometimes used to provide at-home Internet connections.
As Compared to 3G
The main difference between 4G mobile technology and the previous standard, 3G technology, in terms of end usage is the data transfer speeds provided. This means that users can access much more sophisticated data that requires a lot of bandwidth very quickly. Depending on the service provider, however, 4G mobile devices may be limited to specific zones for making phone calls that are generally smaller than the areas covered by 3G. This means that people trying to make a call would have their call dropped if they went outside the covered area. Some 4G phones also have much shorter battery life than most 3G phones.