You've probably heard the term 4G thrown casually into conversation by mobile phone aficionados, but what does it actually mean? In simple terms, 4G refers to the fourth generation of wireless technology networks and follows on from 2G and 3G.While 1G refers to the first batch of widely available handsets; 2G switched to a digital system, bringing with it the introduction of text messaging; then 3G technology offered huge improvements, not least the possibility of easy web browsing and now 4G has been developed to cope with the rate requirements set by further evolution of existing 3G applications like text messaging, video calling and mobile TV.In short, all the improvements that have been added to your fancy smartphone, such as HDTV capability, need more advanced technology and more speed, and the 3G network simply won't be able to cut the mustard indefinitely. 4G is the answer to that problem.\n\nUp until recently, 4G has been used as a catch-all marketing term for the next generation of mobile services as until October 2010 there was no definitive, industry-set criteria for what constitutes a 4G network. The ITU (International Telecommunication Union) only recently made things official and that meant that none of the the so-called 4G networks available in the US or elsewhere in the world before the definition was coined officially qualified.No doubt ruffling a few feathers among the networks, the ITU states that there are now only two major technologies in development that can be classed as 4G - LTE-Advanced and WiMax 2 - both of which are enhanced versions of what carriers currently describe as 4G and both of which have only recently began rolling out across the globe. So, as it stands, what was being sold as 4G by many networks was actually only HSPA+ and only really 3.5G. But we digress.\nAccording to the ITU - a UN agency that regulates information and communication technology issues and coordinates the shared global use of the radio spectrum -\u00a0there are various standards that true-4G networks will need to offer in the future. Only those that meet these will be awarded the status of IMT-Advanced (International Mobile Telecommunications Advanced) and in turn, the title of 4G.The list of requirements declares that a 4G network must be able to exchange data at a rate of up to 100 Mbps. To put that into perspective, data speeds on a 3G network can currently be as slow as 3.84 Mbps, so it's a considerable leap.The benefits for 4G users mainly come down to internet speeds, so if that's not an issue for you, then you probably don't need to worry just yet. The greater capacity offered by 4G means that it can be used for internet access on computers, without the need for cabling, and it seems that it's this that will be the very first sort of proposal from the Orange and T-Mobile under EE with a roll out of 4G dongles and smartphones to arriving before the end of 2012.\nMobile networks in the US are currently using different technology from one another to make 4G possible (or what everyone is calling 4G, despite the ITU's new criteria) . While Sprint uses WiMax technology, Verizon Wireless uses Long Term Evolution (LTE for short) and T-Mobile offers HSPA+ - a 3G technology with 4G speeds. Verizon will support up to 5-12Mbps and Sprint's WiMax can reach a headline offer of 3-6Mbps, in comparison with the maximum 100Mbps that will be required from true 4G networks.The services are currently limited to urban areas but Verizon recently added another 49 US cities to its 4G coverage map, taking the total for 2011 up to 102 with the carrier promising nationwide coverage by 2013.\u00a0As for Sprint, the network is gradually increasing its 4G offering and states that its WiMax system currently covers more than 40 million possible people. Naturally, all of them aren't actually using it. Sprint puts WiMax at around 2.5GHz on the spectrum, which isn't too far from where 3G sits in the UK so, in theory, it should have a similar kind of coverage from each mast.Operating on similar principles to Wi-Fi, WiMax can cover distances of up to 30 miles. As with all wireless technologies though, WiMax can operate either at higher bitrates or over long distances, but not both. Operating at its maximum range of 50km (just over 30 miles) will result in a much lower bitrate, so lowering the range means higher possible speedsSo that's the state of play for those lucky early adopters o'er the Pond but, just because we're finally getting 4G over here, don't expect any US 4G handsets to work over here. The radios within them operate on entirely different frequencies.Ofcom\u00a0unveiled plans for the UK's 4G auction.\u00a0According to the independent regulator, the additional space that will be freed up for 4G makes up 75 per cent of the current mobile spectrum and is 80 per cent more than the space that went under the hammer during the 3G auction in 2000. The 4G spectrum will comprise two bands - with the 800 MHz frequency becoming available thanks to the analogue TV switch-off and the 2.6GHz section offering high speeds for all your HD-laden mobile devices. The auction will be split into five 'spectrum floors' so that all of the big networks will be able to throw their hats into the ring, while they'll be a couple of safeguards in place to keep things fair and make sure that none of the operators gain an unfair advantage.While Everything Everywhere has got the drop on the others with the launch of the EE 4G UK handsets, mobile broadband devices and 4G network, we do know that testing has already been carried out with all of the other operators too. So, it's only a matter of months before you network will have something big to say about it.So what can you expect? Well, downstream speeds in excess of 20Mbps, some fairly limited coverage to begin with and a glut of interesting devices to work on it beginning 2013.This article was first published on 18\/01\/2011.