Existing mobile networks use 3G/UMTS technology, which is now almost 10 years old and struggling to cope with the needs of today's data hungry users.
4G/LTE (Fourth Generation / Long Term Evolution) is the next stage in mobile network development and will provide users with much faster data speeds than 3G is able to. In fact 4G is already being used in various places including the US, but the UK is a bit late to the party.
That's all set to change though, will the arrival of EE's existing 4G service (more on that below) and the upcoming 4G mobile radio spectrum auction starting in January 2013.
Ofcom has announced that 4G spectrum auctions are due to start in January and that licences are expected to be granted in February and March.
The auction is for a big swathe of the UK's spectrum (800 MHz and 2.6GHz) occurs early next year, and communications regulator Ofcom has named the seven bidders for the sections of spectrum.
As well as EE, the other bidders are Vodafone, O2 (Telefonica) and Three (Hutchison Whampoa). Less familiar to many will be PCCW - a Hong Kong-based telecoms conglomerate and MLL Telecom - a Bucks-based network supplier.
Rounding out the list is BT - through its subsidiary Niche Spectrum Ventures.
"New 4G services will stimulate investment, growth and innovation in the UK, and deliver significant benefits to consumers in terms of better, faster and more reliable mobile broadband connections," said Ed Richards, Ofcom's chief executive.
Those benefits principally mean faster data transfer, with 4G all set to bring in things like streaming HD video on the go, video calls and super-fast surfing.
What is EE?
4G arrived in the UK on 30 October 2012 courtesy of a new joint venture between Orange and T-Mobile named Everything Everywhere, or 'EE' for short.
EE was granted permission by Ofcom to use part of its existing 3G bandwidth for 4G, which is why it got a head start on everybody else in October 2012. As you can imagine, rival networks were somewhat unhappy about this decision, but part of the deal for EE to get this head start was that it had to sell off a chunk of their 1800MHz spectrum.
This chunk was promptly snapped up by Three, so it's possible that it may also take advantage of the head start and begin rolling out their own 4G service in early 2013.
For the time being, EE is the only provider of 4G services in the UK and their 4G network is currently available in 11 of the UK's major cities (London, Leeds, Liverpool, Manchester, Sheffield, Glasgow, Edinburgh, Cardiff, Bristol, Birmingham and Southampton).
Tariffs are expensive - you'll pay £36 per month for just 500GB of data.
If you're based in Belfast, Derby, Hull, Nottingham or Newcastle, don't fret, because you'll also be getting 4G by the end of 2012. Bradford, Chelmsford, Coventry, Doncaster, Dudley, Leicester, Luton, Newport, Reading, Rotherham, St Albans, Sunderland, Sutton Coldfield, Walsall, Watford, West Bromwich and Wolverhampton aren't far behind, and will have 4G by March 2013.
For everybody else, you can still buy one of EE's 4G handsets and use the 4G services in any of the above cities, but you'll have to wait a bit longer to get 4G where you live.
If you're interested in comparing the best deals for all of EE's phones, head over to the TechRadar Phonestore and compare all the 4G capable models in one place.
4G coverage: When will all of the UK get it?
Although all of the networks will have 4G services by late 2013, they will of course focus their efforts on major cities first in an effort to service the most users. Ofcom's targets say that 4G must reach 98% of the population and 95% of the country by the end of 2017, but EE claim that it will cover 98% of the country by the end of 2014, so 4G coverage may be closer than you think. EE are also improving the speeds of their 3G networks by upgrading them to DC-HSPA in an effort to improve speeds when 4G services aren't available.
Is 4G WiMAX?
Yes and no: 4G is a blanket term for this generation of mobile networks, so whilst WiMAX is a 4G (Fourth Generation) technology, 4G doesn't necessarily mean WiMAX. In fact, in the UK all the networks have thrown their weight behind the other 4G technology: LTE, largely because it's cheaper to implement than WiMAX.
Are the new 4G phones any good?
The 4G phones currently available in the UK are basically just LTE-equipped versions of current top-end 3G phones, such as the iPhone 5, Samsung Galaxy S3, and HTC One X. One of the advantages to being late to the 4G party is that we're spared the naff "first try" handsets that we suffered back when 3G came out, so don't be shy to try the new 4G phones.
Will I be able to import a 4G phone and use it in the UK?
Perhaps. 4G is available in various different frequency bands, so you'd have to buy a phone that could run on one of the bands being used in the UK.
For the time being that means getting a phone that runs on the 1800MHz frequency band that Everything Everywhere are using. Next year you'll also have the option of 800MHz and 2.6GHz bands, once those frequencies have been auctioned off to other carriers. To confuse you even further, there are WiMAX networks like Sprint use in the US.
Phones made for a WiMAX network, such as the HTC Evo Sprint 4G, will not connect to UK LTE networks. Then on top of this there are handsets labelled as 4G which aren't actually true 4G, such as HSPA+ devices like the US Motorola Atrix 4G. Our advice is to buy a UK handset that you know will work, or possibly hold on 'til there's more competition in the 4G arena and prices start to drop.
Will the 4G iPad work in the UK?
Unfortunately not: whilst you can buy a 4G iPad in the UK (called WiFi+Cellular), its 4G radio works on the 700MHz and 2100MHz frequency bands, not the 1800MHz band that EE are using, nor the 800MHz or 2.6GHz bands that are due to arrive in 2013.
What are the 4G download speeds?
Well so far we can only comment on Everything Everywhere's network speeds, as this is the only 4G network available at time of writing, but it's certainly impressive.
EE boasts speeds typically five times faster than current 3G networks, though on several occasions we found it to be ten or more times faster than a comparable 3G handset in the same area. In use it just makes everything feel much snappier and ensures tasks like checking image-laden emails and browsing complex web pages is a breeze.
What is NFC and why is it in your phone?
EE claim average download speeds of 8-12Mbps and typical maximum speeds of 40Mbps, with upload speeds averaging around 5-6Mbps with a typical maximum of 15Mbps. Whether the other networks will achieve any higher remains to be seen next year, but 4G download speeds could theoretically exceed 100Mbps with upload rates of more than 50Mbps, though it's unlikely we'll see anything like that in the near future.
Why is 4G so fast?
4G's impressive speed increase is achieved with the use of OFDM (Orthogonal Frequency Divison Multiplexing), a transmission technology used by the likes of ADSL, Wi-Fi, DVB-T, DVB-H and DAB. Not only does it reduce latency, but it also minimises interference and is able to cram greater amounts of data into the same slice of radio bandwidth.
Simply put, this enables 4G/LTE phones and tablets to stream video and play online games like never before, largely because 4G has been designed primarily as a data network, rather than a voice one, and it uses the same TCP/IP protocols that underpin the internet.
It's possible that further increases in speed could be achieved with MIMO (Multiple Input Multiple Output) technology, which uses multiple antennas on transmitters and receivers like 802.11n Wi-Fi equipment.
Nokia has reportedly achieved 173Mbps from LTE with a 2x2 MIMO configuration (two antennas on both the transmitter and receiver), so a 4x4 arrangement could potentially offer as much as 326.4Mbps. Perhaps we'll see this on the iPhone 10.