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5G technology: discover how it actually works

5G technology
(Image credit: Verizon)
Complete guide to 5G

What is 5G?: Discover the use cases
5G Dangers: the fact and fiction
5G Internet: will it replace fibre
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Wireless networks have remained largely unchanged for years.

While speeds have increased and latency has dropped, the technology underpinning these networks works in the same way it always has and it’s reached a breaking point. 5G technology promises to solve this by overhauling how a wireless network looks and works, not only for today’s devices but to futureproof the network against surging demand. 

When fully operational, 5G networks will come in a variety of “flavours” depending where on the spectrum they lie and the technology behind them. Each of these flavours offer pros and cons when it comes to speed and reliability, and each are reliant on different technologies.  

 The main 5G technology “flavours” 

5G Plus

The high-end speeds regularly quoted by manufacturers and in the press when talking about 5G – around 1.5Gbps – are commonly referred to as 5G Plus or Total 5G. These speeds are the maximum achievable in real-world scenarios, rather than lab tests, and will come via high frequencies over millimetre waves (mmWaves); around the 30GHz plus mark. At these levels consumers will have to trade coverage for high speeds until networks are built using a specific set of antennas and systems.

Standard 5G

Standard 5G – often referred to as “sub-6GHz” 5G – describes the types of 5G networks we’ll mostly use on a daily basis. Delivered to complement existing 4G technology and sit in largely the same area of the spectrum, signals will travel in bands that sit below 6GHz, predominantly 3.5GHz and above, and will combine spectrum from multiple operators to boost capacity. Top speeds are lower than those seen under 5G Plus – in tests, these have been shown to reach 490 Mbps compared to 4G speeds of 56Mbps – but coverage is vastly improved.  

Coming soon: industrial 5G

Although not one of the top three flavors at the time of writing, industrial 5G - where it is used to power IoT devices on the factory floor, and within the manufacturing space - is going to be huge. But it will rely on mix of standards, including 4G, 5G, and even Wi-Fi services, such as CBRS (3.5 GHz), private LTE, LAA, and the upcoming Wi-Fi 6, which has a theoretical throughput of 9.6 Gbps. 

5G Minus/4G LTE Plus

This flavour refers to 5G services which aren’t technically 5G but are being marketed as such. This means they fall short of the minimum requirements for 5G set by the International Telecommunication Union but are greater than those offered by Gigabit LTE.

As networks mature the gaps between these definitions will shrink, like they did between 4G and 4G LTE, and 5G will become a catch-all for fast speeds with low latency.

 5G technology and how it works 

This graphic shows how 5G technology will work in cities 

This graphic shows how 5G technology will work in cities 

(Image credit: US State Dept./S. Gemeny Wilkinson)


To understand how 5G technology works, it’s worth explaining how it differs from the networks that preceded it. 3G and 4G networks are centralised systems focused, predominantly, on getting the fastest throughput of data via a base station linked to a device. 

To boost speeds, operators aggregate signals and send data across multiple bands to boost bandwidth, known as carrier aggregation. This focus on speed and latency has historically neglected connection density so when an increasing number of devices came online, the networks weren’t set up to cope.

This means communication between end devices will play a larger role and it will be technically impossible for them to be linked centrally like they have been before. 5G networks, therefore, rely on emerging technologies to meet these new network demands. 

Firstly, they operate on higher frequencies. These boost bandwidth but provide less coverage than those further down the spectrum. To increase coverage, thousands of cells will need to be installed on networks and advanced antennas with signal processing technology will be required to manage the increase in connection and signal density. Let’s break this down. 

Millimetre waves 

Building on carrier aggregation improvements made in LTE technology, 5G standards aim to boost speeds by offering more frequency support – up to 40Ghz, pushing into the millimetre wave (mmWave) portion of the spectrum. Previous support extended to 6GHz. 

These higher bands have never been used for mobile devices, meaning they’re clear of clutter and are well suited to densely populated areas because they offer higher bandwidth than lower frequencies. Opening up the spectrum will help lighten the load on the more crowded, lower frequencies, in turn freeing up even more bandwidth, boosting speeds further and increasing overall capacity. 

The major downside is that these waves carry data over much shorter distances and are blocked by buildings, trees and just about any obstacle they come into contact with. For comparison, 2.5GHz waves are around 12cm in length, 60GHz are just 5mm long. These mmWaves are also easily absorbed by plants and rain so using these frequencies requires the use of another technology called small cells. 

Small cell networks 

Small cells aren’t new. The term is a catch-all that describes mobile base stations used to boost signals in indoor areas, such as shopping centres; boost network capacity in crowded places such as sports stadiums; and help strengthen signals in remote outdoor locations. These small cells get their connection via a macrocell before sending data from one small cell to another in a relay. This helps carry signals over much larger distances. 

 Samsung has proposed fitting 5G-capable small cells to existing street lights and lampposts to provide 5G to homes 

 Samsung has proposed fitting 5G-capable small cells to existing street lights and lampposts to provide 5G to homes 

(Image credit: Samsung)


Current 4G systems already use large towers fitted with cell sites that send signals to existing networks of macro and small cells. For 5G signals sent over mmWave, the number of these small cells will need to increase exponentially and be placed much closer together to move the shorter waves from one site to the next without a user dropping connection or losing speed. One solution, put forward by Samsung, is to fit 5G cells to existing street lights and lampposts

MIMO and Massive MIMO

The 4G bases themselves will also need to be upgraded to handle the higher number of connections to small cells and end devices. Today’s bases are typically fitted with around 12 antenna ports that broadcast information in every direction at once. Current transceivers have to take turns if they want to transmit and receive data on the same frequency, or the data has to be moved to another frequency to avoid hold ups, and this causes congestion. 

The solution? MIMO. MIMO stands for Multiple Input, Multiple Output and is a form of antenna that increases efficiency by doubling the number of transmitters and receivers. Perhaps more importantly, MIMO antennas can send and receive signals over the same channel without the need to take turns which increases capacity without sacrificing spectrum. 

Massive MIMO antennas and stations take this a step further. They can support in the region of 100 ports, which vastly boosts the capacity of the network. Huawei, ZTE, and Facebook’s Massive MIMO systems have successfully tested up to 128 antennas, although commercial models, such as Ericsson’s AIR 6468, average at around 64 transmitter and 64 receiver antennas. 

This significant boost doesn’t come without its challenges, though, and an increase in ports makes the current multi-direction broadcasting used in 4G cell sites unfeasible. There would be too many signals crossing each other which would cause serious interference and negate any of the benefits seen by the increase in capacity. This is where beamforming comes in.

Beamforming

Instead of broadcasting signals in every direction at once, beamforming allows a base station to send a focused stream of data to a specific user or device. As multiple signals are sent and received via the MIMO antennas, beamforming technology uses advanced signal processing algorithms to determine the best “path” for the radio signal to take to reach the user. This includes bouncing packets of data off walls to avoid the signals interacting with each other, thus reducing interference and creating more efficient connections. 

Will 5G technology replace Wi-Fi? 

Beyond mobile phone speeds, 5G’s other potential is as a replacement for fixed-line broadband by offering similar speeds without lengthy contracts. In fact, 5G technology can be viewed in a similar way to Wi-Fi. Small cells are akin to Wi-Fi boosters, carrying the signal from your router to dead spots, just on a much larger scale. Beamforming is similarly already used in routers to help direct and control Wi-Fi signals in the home.

This is why each of the UK mobile operators to go live with 5G services in the UK – Vodafone, EE and Three – are offering mobile devices alongside home broadband, Mi-Fi-style products. 

5G technology and US mobile operators

In the US, all four of the major mobile operators now offer 5G services. AT&T was first, launching its 5G network in 12 locations, expanding more recently to a total of 19. However, at launch it could only be accessed by the 5G Netgear Nighthawk router and the first phone, the Samsung Galaxy S10 5G, only launched for business customers in June.

The Verizon 5G network didn't launch until April but is available on more devices and is live in nine cities from Chicago and Minneapolis to Indianapolis and Phoenix. A total of 30 cities are due to go live by the end of the year, including Boston, Dallas and San Diego. The phones included in the launch include the Samsung Galaxy Note 10 Plus 5G, Samsung Galaxy S10 5G, LG V50 ThinQ 5G and the Moto Z4.

Verizon, like many others, has been focusing on building up fibre to support the 5G service. But it recently announced that it will use Integrated Access Backhaul (IAB) technology to expand its reach, without needing the additional fibre. Instead, Verizon is looking at IAB technology to deliver 5G,  and effectively link a tower with fibre running to it, to another tower that doesn’t, and all via wireless. (Read the full story here.)

Verizon engineers installing a small cell in Indianapolis

(Image credit: Verizon)


The Sprint 5G offering is live in nine locations, including Chicago, Houston, Los Angeles and New York. Instead of the Moto Z4, Sprint's phone line-up adds the OnePlus 7 and isn't offering the Samsung Galaxy Note 10 Plus 5G. It's also available as a home broadband service with the HTC 5G Hub as being used by EE.

Finally, T-Mobile's service is available in New York, Los Angeles, Las Vegas, Dallas, Cleveland and Atlanta on the Samsung Galaxy S10 5G.

The 5G routers and mobile devices that are already on sale connect to both the 4G and 5G networks. The 4G network is used to control 5G calls, while the 5G network will be used to bolster 4G speeds with the hope being that come 2020, full control can be moved onto the 5G networks and we’ll finally experience the possibilities of true 5G.

5G technology and UK mobile operators 

EE was first, launching its EE 5G network at the end of May. Its initial focus is on connecting 5G-ready phones to this network in six UK cities but plans to launch a home broadband service later this year via a HTC 5G Hub. This Android-based hub features a Qualcomm Snapdragon X50 5G Modem. 

The Three 5G offering took an alternative route, going live with a 5G router first and announcing plans to launch its mobile 5G offering later in the year. Using the Huawei 5G CPE Pro router, powered by the 5G Balong 5000 chipset and two lots of dual MIMO, sub-6 GHz antennas, the router promises speeds of up to 1.6GBps. 

“5G is going to make home broadband simpler, faster, stronger,” explained Three. “When you get a 5G hub, you just plug in and you’ll get incredible speeds that’ll give traditional fibre and cable providers a run for their money.”

Vodafone 5G currently has the widest offering, launching its mobile service in seven cities at the start of July alongside its GigaCube home broadband router. The GigaCube uses the same router as Three – the Huawei 5G CPE Pro –so offers the same theoretical speeds, however, it will connect to Vodafone’s 5G spectrum instead of Three’s.

Victoria Woollaston is a freelance science and technology journalist with more than a decade’s experience writing for Wired UK, Alphr, Expert Reviews, TechRadar, Shortlist and the Sunday Times. She has a keen interest in next-generation technology and its potential to revolutionise how we live and work.