4G vs LTE: What's the difference?

Tech jargon is confusing at the best of times, but 4G is a real minefield. We explain the differences between 4G and LTE to help you understand.

4G, LTE, LTE-A, carrier aggregation. It's all tech nonsense if you don't understand what the jargon means. Here we explain the differences between 4G and LTE so you're better equipped to choose not only the best phone, but also the best tariff.

These days, there are a lot of decisions to make when getting a new phone. Along with deciding which handset is best for you, you might also have to choose a new tariff, and that's a complex business in itself.

4G is the big buzzword you'll hear or see, but what exactly is 4G? Is it the same as LTE? In a word, no, but phone manufacturers and mobile operators love to use them interchangeably, and further muddy the waters with dumbed-down marketing materials.

In this article, we'll explain everything you need to know about 4G, the speeds you can expect to get and equip you to choose a phone and tariff that's right for you.

What is 4G?

The International Telecommunications Union-Radio (ITU-R) is the United Nations official agency for all manner of information and communication technologies, which decided on the specifications for the 4G standard in March 2008.

It decided that the peak download speeds for 4G should be 100Mbit/s for high mobility devices, such as when you're using a phone in a car or on a train.

When you're stationary, (low-mobility local wireless access) it decided that 4G should be able to deliver speeds up to around 1Gbit/s.

If true 4G is supposed to offer us download speeds of up to 1Gbit/s, then why are we getting 100x less in the UK, at around 10-12Mbit/s in real-world speeds

Unfortunately the ITU-R doesn't have control over the implementation of the standard, which led to first-generation technologies like LTE being criticised for not being up to scratch with true 4G. (We'll explain LTE in a minute.)

The reason for this is that other groups (3GPP being an example) that work with the technology companies who develop the hardware had already decided upon next-gen technologies, leaving us with sub-standard 4G capabilities.

What is LTE?

Though originally marketed as 4G technology, LTE (Long Term Evolution) didn't satisfy the technical requirements that the ITU-R outlined, meaning that many early tariffs sold as 4G weren't actually 4G.

However due to marketing pressures and the significant advancements that LTE brings to original 3G technologies, the ITU later decided that LTE could be called 4G technology.

So, LTE is a first-generation 4G technology that should theoretically reach speeds of around 100Mbit/s. Unfortunately, Ofcom reports that the UK average is around 15.1Mbit/s. While that's around twice the speed of an average 3G connection, it's a long way off from the theoretical top speed of LTE.

As well as lacking in overall download speed, LTE also lacks uplink spectral efficiency and speed. Uplink spectral efficiency refers to the efficiency of the rate that data is uploaded and transmitted from your smartphone.

It falls short of the true 4G capacity mainly because of the lack of carrier aggregation (explained below) and because phones don't have enough antennae.

That's where MIMO (Multiple Input Multiple Output) comes in. It's a practical technique for sending and receiving more than one data signal on the same channel at the same time by using more than one antenna.

With better carrier aggregation and MIMO, we can head towards a new standard: LTE Advanced. This is also known as 'true' 4G.

Imagine playing a PlayStation 3 when you could be playing a PlayStation 4. The PS3 isn't necessarily too slow to use, but you'd have a better experience using the faster console, the PS4. It's the same with LTE - LTE is the PlayStation 3 and LTE Advanced (LTE-A) is the PlayStation 4.

What is carrier aggregation?

Carrier aggregation is part of LTE-Advanced and lets operators treat multiple radio channels in different or the same frequency bands as if they were one, producing quicker speeds and enabling users to be able to perform bandwidth hogging activities like streaming HD video much faster than ever before.

Think of your wireless connection as a pipe. You can't increase the size of the pipe, but you can add a second and third pipe. Use all three simultaneously and you'll have three times the flow rate. It's the same concept with carrier aggregation.

Another advantage of carrier aggregation is that speeds don't decrease, no matter how far away from the cell tower you are.

Combining two signals - or channels - should theoretically double the download speed to around 150Mbit/s. In the future, there could be aggregation across more than two channels, potentially up to five, which was defined in the LTE Advanced standard.

What about HSPA+?

HSPA+ may be marketed as 4G technology but it's technically 3G. HSPA+ stands for High Speed Packet Access Plus. It was the next step after 3G, with UK network provider Three aiming for it to be used by 2012 (before the introduction of LTE).

The technology was developed with a theoretical top speed of 21Mb/s, which is pretty impressive for technology that doesn't count as 4G (3G has an average speed of around 1Mb/s). However, it was quite a way away from its theoretical top speed as the average is around 4Mb/s.

Who offers the fastest 4G LTE connection?

Now you know more about what the difference is between true 4G and the 4G LTE we're being sold, which UK network provides the best 4G LTE connection? In November 2014, Ofcom tested the 3G and 4G connections of every major provider in the UK in five cities.

The results proved that EE has the fastest 4G LTE connection, measuring in at 18.4Mb/s on average, though still far from the theoretical top speed of LTE. 

It's not just the download speed that dictates overall responsiveness of a 4G connection; latency also plays an important part. A lower latency provides better responsiveness and reduced delays when using data for browsing, video calling, etc.

Surprisingly, EE wasn't the best provider when it came to latency - that award went to Three. Ofcom reports that Three took the least time to deliver data on both 4G (47.6ms) and 3G (53.8 ms), while O2 came last with the highest levels of latency, measuring in at 62.7ms on 4G and 86.4ms on 3G.

LTE-A availability

LTE-A is already available in selected areas - Vodafone started its LTE-A rollout in Birmingham, Manchester, and London, while EE offers it in most major UK cities.

Upgrading infrastructure to support LTE-A will be a slow process and is likely to take a couple of years, much like the initial 4G rollout. You won't automatically get LTE-A though: there are other factors that have to be taken into consideration.

The main one is compatibility. Your phone be need to support LTE-A. As with the 3G to 4G migration, many existing phones don't have the technology to be compatible with LTE-A. The good news though is that most recent devices, especially flagships, support the tech including:

iPhone 6s onwards
iPad Pro
Blackberry Priv and Passport
Google Pixel and Pixel XL
HTC One M9, A9, and 10
Moto Z and X Style
LG G3 onwards
Huawei Honor 6, Mate 8, and P9 onwards
OnePlus 2 onwards
Samsung Galaxy S5 onwards, Notes S4 onwards, and A-series
Sony Xperia X, XZ, and Z3 onwards

The good news is that it appears that both Vodafone and EE aren't charging people for the extra speed. As long as you're in a supported area and using a compatible phone, you should be able to enjoy the benefits of LTE-A's carrier aggregation and see (theoretical) download speeds of around 150Mbit/s. Just watch out you don't burn through your monthly data allowance in a few minutes!

This story, "4G vs LTE: What's the difference?" was originally published by PC Advisor (UK).

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