The first phones sold as 4G did not meet the official definition of 4G
In 2008 the international telecoms standards body set targets for 4G, including peak speeds of 1 gigabit per second for stationary users. The first networks carriers marketed as 4G, early LTE and Mobile WiMAX, fell well short. In 2010 regulators relented and let the label stand anyway, then in 2012 called those networks merely transitional.
Fourth-generation cellular networks arrived in the late 2000s and early 2010s. Their defining break from 3G was abandoning traditional circuit-switched phone calls: everything, voice included, travels as internet protocol data. Much greater bandwidth made high-definition streaming practical on phones and helped the Internet of Things expand.
The official rulebook, called IMT-Advanced and issued by the radio arm of the International Telecommunication Union in November 2008, demanded roughly 100 megabits per second for users on the move, such as in trains and cars, and around 1 gigabit per second for pedestrians and people standing still. It also required an all-IP network, flexible channel widths and smooth handovers between networks. The union sets such requirements but leaves the actual engineering to groups such as 3GPP and IEEE.
Marketing moved faster than the standard. When first-release LTE and Mobile WiMAX launched, some experts dubbed them pre-4G or 3.9G. On December 6, 2010, the union accepted that such systems could be called 4G if they were forerunners of compliant versions and substantially better than early 3G. The truly compliant upgrades, LTE Advanced and WiMAX Release 2, were standardised in spring 2011, and in January 2012 the union declared only those to be true 4G. Some carriers sidestepped the argument by labelling the upgrade 4G+, as Vodafone Netherlands did.
Under the hood, 4G dropped the spread-spectrum radio used by 3G in favour of OFDMA, which splits signals across many carriers and copes better with echoes as radio waves bounce around, and it boosted speeds with multi-antenna MIMO arrays. Generations have tended to arrive about once a decade: analogue 1G in 1981, digital 2G in 1992, 3G in 2001, and full 4G around 2011 and 2012. Each brought faster speeds, new frequency bands and technology that could not talk to the previous generation.
Source: 4G
