What is 4G?

4G promises superfast broadband speeds to your regular mobile phone, but it's a complicated area. In this guide we try and explain 4G, but be prepared, there are quite a few technical terms here. We'll try our best to give you all the facts without your brain being fried!

4G Information

All 4 UK operators (3, EE, O2 and Vodafone) support 4G but in various guises. 4G rollout is also a work in progress - the operators have naturally opted to roll it out in large cities and towns first before taking it to the less populated areas.

Current situation

To start with let's discuss the current state of our mobile network here in the UK. We have many flavours of technologies that support mobile connectivity, but loosely they are grouped into 3 distinct tiers; 2G (2nd generation), 3G (3rd generation) and 4G (4th generation). 2G may also be referred to as GSM (Global System for Mobile), 3G as UMTS (Universal Mobile Telecommunications System) and 4G as LTE (Long Term Evolution).


2G came out in the 1990s and supported calls, text messages (SMS - Short Message Service), picture messages (MMS - Multimedia Messaging Service) and Internet (WAP - Wireless Application Protocol).

Whilst the technology worked, the speeds (compared to today) were poor. The GSM networks in the UK use the 900MHz and 1800MHz frequencies and from 1997 used GPRS (General Packet Radio Service) to support data transmission (such as WAP or SMS) up to 80kbps (kilobits per second).

From 2003 a new data transmission standard known as EDGE (Enhanced Data for GSM Evolution) was established which enabled faster transmission (up to 237kbps).


3G also came along in 2003 to give us broadband video calling and download speeds up to 3.1Mbps (megabits per second).

HSPA (High Speed Packet Access) was an improvement to 3G which gave transmission speeds of up to 7.2Mbps.

HSPA+ (High Speed Packet Access Plus) came along in 2011 which gave transmission speeds of up to 21Mbps. This was again further improved with DC-HSPA+ (Dual Carrier High Speed Packet Access) which gave transmission speeds up to 42Mbps.


During the roll-out of 2G and 3G, mobile phone technologies were improving continuously. There were many times where phones did not support the latest technology releases, so you stayed older, slower technologies. We are currently seeing the exact same thing happen again with 4G.

Furthermore, this problem is compounded by the fact that 4G is currently supported on three separate frequencies in the UK - 800MHz, 1800MHz and 2600MHz. There are many phones that may classed as 4G (or LTE) but because they do not support any of the above frequencies, or the network provider you are using does not support 4G on the band your phone supports, it cannot get 4G.

4G frequencies have been allocated or auctioned off by Ofcom to the 4 UK Operators at various points in time. EE was given early access to running 4G in 2012 before Ofcom auctioned off remaining frequencies in 2013. EE therefore have a large allocation of 1800MHz frequency available.

LTE (Long Term Evolution - aka 4G) supports up to 150Mbps download speeds (but doesn't actually currently support voice calls!). Some operators are also rolling out the newest standard known as LTE-A (Long Term Evolution Advanced) which can theoretically run at up to 300Mbps download.

All of the download speeds we have mentioned are theoretical. These are speeds which are possible in laboratory conditions without any interference, walls to go through and where the network isn't congested with people. Obviously in the real world there are many factors which can slow down performance, plus the operator needs to have the necessary backhaul capacity (their connection to the Internet) to support many simultaneous users downloading and uploading data.

4G Frequencies

In the table below we detail which frequencies offer 4G on each of the 4 networks.

Lower frequencies penetrate buildings much better than higher frequencies, whereas higher frequencies have higher capacity than lower.

The more MHz of each spectrum a network has, the better and more consistent the connection available, as it is able to support more concurrent users.

800MHz (Band 20) 1800MHz (Band 3) 2600MHz (Band 7)
3 5MHz
(2015 rollout)
EE 5MHz 45MHz 35MHz
O2 10MHz
Vodafone 10MHz 20MHz

As you can see, EE has frequency allocation across all three bands, making it a strong player for 4G. 3 has a trade-off between penetration and speed with their 1800MHz allocation. Vodafone has allocation at either end whilst O2 seems to have the poorest offering with only allocation at the 800MHz band.

It is also worth noting how much the operators have paid for 4G frequencies. EE was able to re-allocate their 1800MHz frequency from 3G to 4G, whereas other Operators had to wait to purchase 4G via auction.

Network Cost Frequencies
3 £225,000,000 5 MHz of 800 MHz
EE £588,876,000 5 MHz of 800 MHz
+ 35 MHz of 2.6 GHz
O2 £550,000,000 10 MHz of 800 MHz
Vodafone £790,761,000 10 MHz of 800 MHz
+ 20 MHz of 2.6 GHz

Frequency Confusion

When looking at the specifications of a phone to see if it can support 4G in the UK, ideally you should look for the band numbers listed in the table above so that you can be sure that it will support 4G.

There can be some confusion with the MHz numbers, as bands are different in different areas of the world. For instance, when the iPhone 5 was released it was quoted that it supported 850MHz. Unfortunately the US 850MHz frequency is not compatible with the UK 800MHz frequency (even though many assume the 800MHz band runs from 800MHz to 900MHz - it in fact runs from 791-862MHz).


Mobile virtual network operators such as Tesco, giffgaff and Virgin use one of the 4 UK network operators. However, this does not necessarily mean that they support 4G. They will have their own roll-out plans, so you will need to check directly to see if they support 4G. Some will require you to sign-up to a new contract, get a new SIM card, or perhaps run a software update on your handset.

Why is 4G/LTE important?

Improved mobile network technologies mean improved speeds, as well as improved latency (better response times). In the table below we detail the speed differences between technologies, using GPRS as the baseline.

Technology Theoretical Download Speed Performance
2G GPRS 80kbps
EDGE 237kbps
3G 3G 3.1Mbps
HSPA 7.2Mbps
HSPA+ 21Mbps
DC-HSPA+ 42Mbps
4G LTE 150Mbps
LTE-A 300Mbps

There is therefore tremendous potential with 4G to provide great connection speeds, but we will need to wait for mobile phone technology to improve, increased rollout of 4G to more areas, more mobile masts deployed, as well as for the networks to improve their backhaul capacity before more people can realise the potential of 4G.

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