4G, short for fourth generation, is the fourth generation of mobile telecommunications technology, succeeding 3G. A 4G system must provide capabilities defined by ITU in IMT Advanced. Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television, and cloud computing.
Two 4G candidate systems are commercially deployed: the Mobile WiMAX standard (first used in South Korea in 2007), and the first-release Long Term Evolution (LTE) standard (in Oslo, Norway, and Stockholm, Sweden since 2009). It has however been debated if these first-release versions should be considered to be 4G or not, as discussed in the technical definition section below.
In the United States, Sprint (previously Clearwire) has deployed Mobile WiMAX networks since 2008, while MetroPCS became the first operator to offer LTE service in 2010. USB wireless modems were among the first devices able to access these networks, with WiMAX smartphones becoming available during 2010, and LTE smartphones arriving in 2011. 3G and 4G equipment made for other continents are not always compatible because of different frequency bands. Mobile WiMAX is not available for the European market as of April 2012.
What is 4G? A complete guide to 4G
What is 4G? We guide you through the 4G minefield, explaining everything there is to know about the latest mobile broadband technology hitting the UK.
You've probably heard of it, but what is 4G? In short, it's the name given to the fourth generation of mobile networks, just as the previous generation is called 3G.
Another piece of jargon, which you will see tagged onto the end of 4G is 'LTE'. This stands for Long Term Evolution and is a type of 4G technology. It's arriving in the UK for the first time at the end of October and will be available to around a third of the population by Christmas 2012. See also: iPhone 5 review
4G LTE aims to offer users faster, more reliable mobile broadband internet for devices like smartphones, tablets and laptops.
Loosely speaking, 4G is around five times faster than existing 3G services. Theoretically it can provide download speeds of up to 100Mbps but you won't achieve this in real-world use.
Unless you've just bought an iPhone 5, a Samsung Galaxy S3 LTE (not a regular S3) or one of the other brand new 4G-capable smartphones, your existing handset won't work on a 4G network.
4G networks use different frequencies to transmit data than 3G so you need a handset which has a modem that supports these new frequencies.
Here, we'll explain everything you need to know about 4G. We'll be taking an in-depth look at how the technology works, where and when you can get it as well as telling you which devices support it.
We've been able to test out the first 4G network, run by EE, formally Everything Everywhere, so we can also reveal how fast it is and how it will benefit you in practice.
Although 4G is new to the UK and we Brits like to think we have the latest technology, it has actually been around for many years. Two forms of 4G been developed and are in use: WiMAX and LTE.
In fact, you may recognise the first technology, as WiMAX was trialled in the UK in 2009. However, the first WiMAX network was launched by South Korean firm KT in 2006.
The first LTE network was deployed in Scandinavia in 2009. However, it was debatable whether the speeds on offer back then were really 4G or not.
Across the Atlantic in the US, Sprint has been using WiMAX since 2008 and MetroPCS was the first operator to offer an LTE service in 2010. Verizon and AT&T also offer LTE 4G.
In the UK, 4G networks will use LTE technology, which is why devices such as smartphones are already popping up with LTE suffixes to their names to show they are 4G capable.
3G has, of course, been around for a lot longer than 4G. In the UK the first 3G network was launched by Hutchinson Telecommunications, branded as Three or '3'. Wideband Code Division Multiple Access (WCDMA) was the first technical standard used for 3G.
It's now more commonly known as Universal Mobile Telecommunications System (UMTS). More modern forms of 3G are High Speed Packet Access (HSPA) and HSPA+. The latter allows for faster speeds up to 42Mbps, twice that of HSPA. Common spectrum used for 3G connective include: 850MHz, 900MHz, 1900MHz and 2100MHz.
4G's headline download speed is 100Mbps and a blistering 50Mbps for upload. This makes 4G is more than twice as fast as the latest 3G technology and many more times faster than previous versions.
Of course, these speeds are theoretical, and such speeds won't be reached in real-world use. However, that doesn't mean 4G isn't twice as quick. In our tests, which we'll get to later, we saw speeds around three times faster on 4G compared to 3G, and an even larger improvement with uploads.
What does this mean in practice? The faster speeds mean websites load quicker, and that you'll be able to stream videos and podcasts without first waiting for them to buffer.
Plus, you'll be able to download large email attachments or other content from the web faster. Apps which need to download data, such as maps, will work more smoothly, especially when zooming in or out as this generally requires a lot of data. The speed differential should be akin to switching from 3G to Wi-Fi.
Taking a more demanding task like video streaming, the BBC recommends a connection speed of 3.5Mbps for HD content. Although 3G can offer speeds in excess of this, the average speed across all forms of 3G in the UK is around 3Mbps.
For video streaming and similar tasks, where you would typically require Wi-Fi for smooth performance, 4G should allow you to have a 'home broadband' experience on the move. EE expects the average speed to be between 8- and 12Mbps, potentially faster than the 5.9Mbps average for ADSL home broadband.
Faster upload speeds will also be a boon. If you hate waiting for pictures to be posted to Facebook or Twitter, for example, then this should be a much faster process over 4G.
What is 4G: technology
The main reason 4G is faster than 3G is because of Orthogonal Frequency-Division Multiplexing (OFDM). It sounds complicated, but it's the same technology used in Wi-Fi, ADSL broadband, digital TV and radio.
OFDM is a technique for squeezing more data onto the same amount of radio frequency. It also reduces latency and interference. Data is split up and sent via small chunks of frequency in parallel, therefore increasing the capacity of the network.
Multiple-input and multiple-output, or MIMO, is another reason 4G is able to provide faster speeds. It is simply the use of multiple antenna arrays at both the transmitter and receiver to improve communication performance.
This allows more data to be transferred without requiring additional bandwidth or drawing more power. The most common configuration currently is a 2x2 MIMO, found in many smartphones and some tablets. A 4x4 setup is also possible and promises even faster speeds but is still a little way off making its way onto devices. Since different setups are possible, one phone could provide faster 4G speeds than another.
With 3G handsets, most of us take roaming for granted. We take our phones travelling around the world, and expect to be able to pick up emails and browse websites as soon as we land. Things are different with 4G.
Although there are 4G networks in many countries around the world, your UK 4G smartphone won't necessarily work wherever you go. The reason is that 4G doesn't operated on the same frequencies in every country.
If your phone's 4G modem doesn't work on the same frequencies as those used in the country you're visiting, then you'll have to live with 3G instead. Even if the numbers do match, there needs to be a 4G roaming agreement between operators. Currently, there is no such agreement in place and even when there is, expect data prices to be high.
What is 4G: UK frequency bands
Frequency spectrum (UK)
What is 4G: coverage in the UK
EE says it will provide 4G coverage in a total of 10 UK cities at launch, with 16 switched on by Christmas. The firm says it means 20 million users will be able to get the faster speeds before the year is over. The lucky cities to get 4G before the rest of the country are:
Birmingham, Bristol, Cardiff, Edinburgh, Glasgow, Leeds, Liverpool, London, Manchester and Sheffield.
Belfast, Derby, Hull, Nottingham, Newcastle and Southampton should be 4G'd up before 2013.
12 cities will have wide-ranging coverage. London 4G's signal will stretch beyond the M25, for example. The remaining four (which four haven't been announced) will have city-centre coverage only to start with.
Don't assume that if you have good 3G coverage now you will also get good 4G coverage when the new network launches in your area.
Ofcom - the independent regulator - has set a requirement that 98 percent of the UK must have 4G coverage by the end of 2017. However, EE has promised the fastest ever roll-out of a mobile network in the UK claiming it will reach 70 percent of the UK by the end of 2013. It says 98 percent of the UK will have 4G available by the end of 2014, three years ahead of Ofcom's goal.
What is 4G: tariffs
There has been, and still is, a lot of bartering between the UK's mobile operators and Ofcom about 4G. EE was the first to launch 4G to the public at the end of October. Until other networks are allowed to roll out their 4G networks EE will have a monopoly and therefore be the only choice.
The process of setting up a 4G network is complicated and involves plenty of red tape so it will be a while before there's a choice of 4G operators.
Ofcom is auctioning off 800MHz and 2600MHz spectrums to be used for 4G: O2 and Vodafone will be the main bidders. Once this process is complete the networks are expected to be rolled out in spring 2013. Ofcom allowed EE to launch a 4G ahead of the rest because it already owned 1800MHz spectrum which it could use for 4G services and to simply get 4G launched in the UK as soon as possible for people to benefit from the faster speeds.
Three has made an agreement with EE to use parts of the 1800MHz spectrum for 4G services but it won't be able to do this until the latter part of next year when it gains approval.
Virgin Media is negotiating with EE to launch 4G tariffs by the end of this year. Since Virgin is a 'virtual operator' and already uses EE's network for 3G, it hopes to simply piggyback on EE's 4G network as well.
Orange and T-Mobile are owned by EE and won't be going anywhere. All three operators will use the EE network and users will begin to see 'EE' displayed on their devices. However, this doesn't mean you're getting 4G.
Existing Orange and T-Mobile customers must switch to EE to gain 4G services – a process which EE said it will make easy and straightforward. It will be free to move, but users will need to sign an 18- or 24-month contract of the same or higher value than their current tariff. A 4G SIM card will be provided free of charge.
Currently, no prices have been announced for EE's 4GEE tariff, and we haven't been able to find out what data limits (if any) will be in place. We'll update this article when that information is available.
Which phones support 4G?
So far only a handful of 4G-capable smartphones have been announced, and even fewer launched. We're sure that plenty more will arrive next year, but for now here's are the 4G handsets to choose between.
Don't forget that you'll need a 4G SIM card and you must be in a 4G area to see that all-important 4G symbol on your phone's status bar. Not all postcodes will be enabled simultaneously on launch day so, again, check EE's website to find out when 4G will be turned on at your postcode.
Apple iPhone 5
HTC One XL
Huawei Ascend P1 LTE
Nokia Lumia 820 LTE
Nokia Lumia 920 LTE
Samsung Galaxy Note 2 LTE
Samsung Galaxy S3 LTE
It's worth bearing in mind that you don't need a 4G smartphone, so all is not lost if you've only just signed a contract on a non-4G Galaxy S3.
An alternative is to buy a 4G mobile hotspot such as the Huawei E589 Mobile Wi-Fi and Huawei E392 MBB Stick. You can connect these to existing devices like smartphones, tablet and laptops via USB or Wi-Fi. The drawback is that you'll be paying for two contracts at once so it isn't a sensible option for most people.
If you're about to buy a new smartphone it's critical to check which 4G networks it is compatible with. Some handsets might claim to be '4G ready' but not work on the UK networks.
If you're buying from an operator you can assume that the handset will work with its network although it's not always that straightforward where 4G is concerned. For example, the iPhone 5 only supports certain 4G spectrums – 850MHz, 1800MHz and 2100MHz in UK. This means it will work on EE and Three's 4G networks but not O2 and Vodafone's since they are bidding for 800MHz and 2600MHz spectrums. You can buy an iPhone 5 from O2 and Vodafone, but it will be limited to 3G speeds.
It's possible that other phones will be similarly limited, so check the supported frequencies before parting with any cash.
4G and tablets
Apple's third-generation iPad is a 4G-capable tablet - at least the Wi-Fi + 4G models - and you'd be forgiven for thinking you can just pop in an EE SIM.
Unfortunately this isn’t the case. As we've said, EE uses the 1800MHz spectrum but the iPad doesn't. Instead, it works on 700MHz and 2100MHz so isn't compatible.
Barring any radical changes, it won't work with any other 4G networks in the UK either. This is exactly why Apple was forced to remove the '4G' element from the iPad's branding. We're sure manufactures will be rushing to be the first to release a 4G tablet which will work in the UK.
Theoretically, 4G can offer download speeds up to 100Mbps and upload speeds of 50Mbps, but how fast is it in reality? We were able to test EE's 4G network in central London prior to its launch to get an idea of how it compares to 3G.
The fastest download we achieved, according to the Speed Test app running on an iPhone 5, was 41Mbps. The fastest upload speed was 14.3Mbps.
Both figures are seriously impressive, but we saw wildly different results as we repeated the test and used different phones.
We were able to run tests on a Samsung Galaxy S3 LTE, Huawei Ascend P1 LTE and HTC One XL. The average download speed was 26.4Mbps and our average upload speed was 14.2Mbps, across nearly 20 tests.
In our side-by-side test with 3G, the 4G network was more than three times faster for downloading and over 10 times faster in upload speeds.
It's fair to say that our results were a best-case scenario, as only a handful of people were using the network.
Also, bear in mind that speeds will depend on many factors such as location and the amount of users fighting for bandwidth.
4G is the fourth generation of mobile phone technology and follows on from 2G and 3G.
2G technology was suitable for making calls and sending text messages while 3G makes it possible to access the internet more effectively through your mobile phone.
What to expect from 4G?
4G services should make it much quicker to surf the web on your mobile, tablets and laptops - speeds will be nearer to what you currently experience with home broadband.
Because of this, 4G is ideally suited for services which demand more capacity like video streaming, mapping and social networking sites.
For the typical user, download speeds of initial 4G networks could be around 5-7 times those for existing 3G networks.
This means a music album taking 20 minutes to download on a 3G phone and just over 3 minutes on 4G. This is based on existing 3G speeds being 1Mbit/s on average and 4G speed being 6Mbit/s (average of 5 and 7 times faster).
What will 4G coverage be like?
Ofcom has designed the 4G auction in a way that will see mobile broadband rolled out to at least 98% of people in villages, towns and cities across the UK. This is for indoor coverage; however, given that it is easier to provide coverage outdoors, a network meeting this obligation is likely to cover more than 99% of the UK by population when outdoors.
Ed Richards, Ofcom Chief Executive, said: 'As a direct result of the measures Ofcom is introducing, consumers will be able to surf the web stream high-quality videos and download big files on their mobile device from almost every home in the UK.'
4G is the short name for fourth-generation wireless, the stage of broadband mobile communications that will supercede the third generation (3G ).
Carriers that use orthogonal frequency-division multiplexing (OFDM) instead of time division multiple access (TDMA) or code division multiple access (CDMA) are increasingly marketing their services as being 4G, even when their data speeds are not as fast as the International Telecommunication Union (ITU) specifies. According to the ITU, a 4G network requires a mobile device to be able to exchange data at 100 Mbit/sec. A 3G network, on the other hand, can offer data speeds as slow as 3.84 Mbit/sec.
From the consumer's point of view, 4G is more a marketing term than a technical specification, but carriers feel justified in using the 4G label because it lets the consumer know that he can expect significantly faster data speeds.
Although carriers still differ about whether to build 4G data networks using Long Term Evolution (LTE) or Worldwide Interoperability for Microwave Access WiMAX, all carriers seem to agree that OFDM is one of the chief indicators that a service can be legitimately marketed as being 4G. OFDM is a type of digital modulation in which a signal is split into several narrowband channels at different frequencies. This is more efficient than TDMA, which divides channels into time slots and has multiple users take turns transmitting bursts or CDMA, which simultaneously transmits multiple signals on the same channel.
When fully implemented, 4G is expected to enable pervasive computing, in which simultaneous connections to multiple high-speed networks will provide seamless handoffs throughout a geographical area. Coverage enhancement technologies such as femtocell and picocell are being developed to address the needs of mobile users in homes, public buildings and offices, which will free up network resources for mobile users who are roaming or who are in more remote service areas.