Introduction

Generally, the term ‘5G’ is used to define the fifth-generation cellular network technology that provides broadband access. Although the agreed definition is actually in dispute by the industry association 3GPP, as it defines any system that uses ‘5G NR’ (5G New Radio) software as ‘5G’. Nevertheless, the term 5G has become more prominent towards the end of 2018.

In any regard, the 3GPP submitted their definition of 5G NR to the International Telecommunication Union (ITU), since it followed the pattern of 2G, 3G and 4G, and their respective associated technologies, GSM, UTMS, LTE, LTE Advanced Pro, etc.

Also, in various parts of the world, 5G carriers have launched numerous differently branded technologies such as ‘5G Evolution’ that advertise improving existing networks with the use of ‘5G technology’. However these ‘pre-5G’ networks are actually improving the existing specification of LTE networks, and are not exclusive to 5G, so they can be described as ‘misleading’.

History of 5G Rollout

Historically 5G was first deployed substantially in South Korea in April 2019, with SK Telecom using 38,000 base stations, KT Corporation 30,000 and LG U Plus 18,000. This provided roughly 85% of coverage to six major cities. The coverage used the 3.5Ghz (sub-6) spectrum in non-standalone (NSA) mode, and recorded speeds of between 193 to 430Mbit/s down. So with such promising results, it was no wonder that 260,000 people have signed up in the first month, a good start to the achieving the overall objective of having 10% of all mobile phones using 5G by the end of 2019.

In America, Verizon opened a 5G service using a very limited number of base stations in the US cities of Chicago and Minneapolis. This service used 400Mhz of 28Ghz millimetre wave spectrum in NSA mode, and download speeds in Chicago were recorded from 80 to 900Mbit/s, and upload speeds of 12 to 57Mbit/s, with a round-trip delay of 25 milliseconds. This was in May 2019, and in the same month, Verizon claimed that the 5G service would regularly hit 1Gbit/s in some locations.

5G Equipment

When South Korea launched its 5G network, all the carriers used Samsung, Ericsson and Nokia base stations and equipment, with the exception of LG U Plus who used Huawei equipment. Samsung was also the largest supplier for 5G base stations in South Korea at launch, shipping 53,000 base stations out of a total of 86,000 installed across the country at that time.

But as of the writing of this article, there are six companies that sell 5G radio hardware and systems for carriers, they are; Huawei, ZTE, Nokia, Samsung, Datang / Fiberhome, and Ericsson.

How The Technology Works

A 5G network is classified as a digital cellular network, in which the service area is covered by providers that are divided into a mosaic of small geographical areas classified as cells. In these cells, analogue signals that represent sounds and images are digitised in the phone, which is then converted by an analogue to digital convertor, before finally transmitted as a stream of bits.

All of the 5G wireless devices in a cell communicate using radio waves with a local array and a low power automated transceiver (transmitter and receiver) in the cell using frequency channels. These channels are assigned by the transceiver from a common pool of frequencies that are reused in geographically separated cells. The local antennas are then connected with the telephone network and the Internet by a high bandwidth optical fibre or wireless backhaul connection. So similar to existing mobile phones, when a user crosses from one cell to another, their mobile service is automatically ‘handed off’ seamlessly to the antenna in the new cell.

The Future of 5G

There are future plans to use millimetre waves with 5G, however since they have shorter ranges than microwaves, the cells will be limited to smaller sizes. In addition, the waves have trouble penetrating through walls. However since millimetre antennas are smaller than the large antennas used in previous cellular networks, typically a few inches long, a massive MIMO (multiple-input-multiple-output) could be used to increase the data rate. This is because each cell would have multiple antennas that could communicate with the wireless devices, which in turn could be received by multiple antennas in the device. Thus multiple bitstreams of data will be transmitted simultaneously.

In parallel, a technique called beamforming from the base station computer will continuously calculate the best route for radio waves to reach each wireless device. This would organise multiple antennas to work together as phased arrays in order to create beams of millimetre waves to reach the device.

Since 5G wireless devices also have backwards compatibility with 4G LTE, the new networks would initially use 4G for establishing the connection with the cell, and providing coverage when 5G is not available.

In comparison to 4G, 5G can support up to a million devices per square kilometre, whilst 4G could only support up to 100,000 devices per square kilometre.

Proposed Uses For 5G

According to the International Telecommunication Union, there are three main uses designated to 5G:

• The first is Enhanced Mobile Broadband (eMBB) that uses 5G as a progression from 4G LTE mobile broadband services, in other words, it aims to offer faster connections, higher throughput, and more capability.

• The second is the implementation of Ultra-Reliable Low-Latency Communication (URLLC) that refers to using the network for mission-critical applications that require uninterrupted and robust data exchange.

• The third use is associated with Massive Machine-Type Communications (mMTC) that would be used to connect to a large number of low power, low cost devices that have high scalability and increased battery lifetime, over a wide area.

however it should be noted that neither URLLC and mMTC are expected to be deployed widely before 2021.

The Expected Speed of 5G

5G NR (New Radio) speed in sub-6Ghz bands can be slightly higher when compared to 4G, especially when using a similar amount of spectrum and antennas. Despite this some 3GPP 5G networks will be slower than some advanced 4G networks, an example of this is the T-Mobile’s LTE/LAA network that achieves 500+Mbit/s in Manhattan. Although the 5G specification does allow Licence Assisted Access (LAA), it has yet to be demonstrated, and by adding LAA to an existing 4G configuration, it can add hundreds of megabits per second to the speed. Although this would be still be classified as an extension of 4G, and not part of the new 5G standard.

In addition, it is proposed that speeds using the less common millimetre wave spectrum can be substantially higher.

In 5G, the ‘air latency’ target is 1-4 milliseconds, although equipment that has shipped so (at least of writing this article) has tested air latency of 8-12 milliseconds. Any latency to the server must be also added to the ‘air latency’ value. Verizon has reported that the latency on its 5G early development is 30ms.

As mentioned earlier, the term ‘5G’ was associated with the International Telecommunication Union’s IMT-2020 standard that required a theoretical peak download of 20 gigabits, alongside other requirements. But since then, the industry standards group 3GPP has adopted the 5G NR standard together with LTE as their proposal for submission to the IMT-2020 standard.

5G NR can also include lower frequencies (FR1), below 6Ghz, and higher frequencies (FR2), above 24Ghz, however the speed and latency in early FR1 deployments, using 5G NR software on 4G hardware (non-standalone) are only slightly better than new 4G systems. This is estimated at being between 15 to 50% better.

Expected Uses of 5G

As noted previously, 5G NR (New Radio) is the new air interface that has been developed for the 5G network, and it is supposed to become the global standard for the air interface of 3GPP 5G networks.

Although some pre-standard implementations of 5G should still be noted:

• 5GTF – the 5G network implemented by American carrier Verizon for Fixed Wireless Access in the late 2010s that uses a pre-standard specification known as 5GTF (Verizon 5G Technical Forum). The 5G service provided to customers in this standard is incompatible with 5G NR, although there are plans to upgrade 5GTF to 5G NR ‘Once it meets our strict specifications for our customers’, according to Verizon.

• 5G-SIG – the pre-standard specification of 5G that was developed by KT Corporation and deployed at the Pyeongchang 2018 Winter Olympics.  

In order to keep up with the development of Internet of Things (IoT) implementation, the 3GPP is planning to submit the evolution of NB-IoT and eMTC(LTE-M) as the 5G technology for LPWA (Low Power Wide Area) use.

This is related to the expectation that 5G will be used in private networks with applications in industrial IoT, enterprise networking, and critical communications. Although the initial 5G NR launches will depend on existing LTE (4G) infrastructure in non-standalone (NSA) mode (5G NR software on LTE radio hardware), before the standalone (SA) mode (5G NR software on 5G NR radio hardware) with the 5G core network will become mature and commonplace. 

The transition to 5G will mean convergence of multiple networking functions designed to achieve cost, power and complexity reductions. Indeed, LTE has already targeted convergence with Wi-Fi band / technology, for example, License Assisted Access (LAA – 5G signal in unlicensed frequency bands used by Wi-Fi) and LTE-WLAN Aggregation (LWA – convergence with Wi-Fi Radio).

However the differing capabilities of cellular and Wi-Fi have historically limited the scope of convergence, but with significant improvements in cellular performance specifications in 5G, combined with migration from Distributed Radio Access Network (D-RAN) to Cloud- or Centralised-RAN (C-RAN) and the deployment of cellular small cells. It is now possible to narrow the gap between Wi-Fi and cellular networks in dense, and indoor deployments.

So finally radio coverage could now result in sharing cellular and Wi-Fi channels through the use of a single silicon device for multiple radio access technologies.

NOMA (non-orthogonal multiple access) is a proposed multiple-access technique for future cellular systems, that could allow same time, frequency, and spreading-code resources to be shared by multiple users via allocation of power. In other words, the entire bandwidth can be exploited individually by users for an entire communication that has reduced latency and increased data rate. So in the case of multiple access, the power domain used by NOMA will determine which power levels will be used to serve different users.

So much like LTE in an unlicensed spectrum, 5G NR will also support operation in an unlicensed spectrum (NR-U), alongside the existing License Assisted Access (LAA) from LTE that enables carriers to use those unlicensed spectrum to boost their operational performance for users.

In addition, 5G NR will also support standalone NR-U unlicensed operations, allowing new 5G NR networks to be established in different environments without first acquiring an operational license for licensed spectrums. This will mean that a localised private network will encounter much lower barriers of entry when attempting to provide 5G Internet services to the public.

Current 5G Implementation and Rollout

As of April 2019, the Global Mobile Suppliers Association has identified 224 operators in 88 countries that are actively investing in 5G. The criteria includes operators that have; demonstrated, testing or tested, trialling or trialled, licensed to conduct field trials of 5G technologies, deploying 5G network or have announced server launches.

In comparison, the equivalent numbers in November 2018 was 192 operators in 81 countries, and the first country to adopt 5G on a large scale was South Korea in April 2019.

To support the increased throughput requirements of 5G, large quantities of new spectrum (5G NR frequency bands) have been allocated, for example in July 2016, the U.S. Federal Communications Commission (FCC) freed up vast amounts of bandwidth in underused high-band spectrum for 5G, and the Spectrum Frontiers Proposal (SFP) doubled the amount of millimetre-wave unlicensed spectrum to 14Ghz. This has created four times the amount of flexible, mobile-use spectrum the FCC had licensed to data. In addition, the European Union lawmakers agreed to open up the 3.6 and 26Ghz bands by 2020.

As of March 2019, there are reportedly 52 countries, territories, special administrative regions, disputed territories and dependencies that are formally considering introducing certain spectrum bands for terrestrial 5G services. This includes holding consultations regarding suitable spectrum allocations for 5G, reserving spectrum for 5G, announcing plans to auction frequencies or have already allocated spectrum for 5G use.

Also in March 2019, the Global Mobile Suppliers Association (GSA) released the industry’s first database that tracks worldwide 5G devices  launches. So far, the GSA has identified 23 vendors that confirmed the availability of forthcoming 5G devices with 33 different devices that include regional variants.

Initially, cellular mobile communications technologies were designed in the context of providing voice services and Internet access. However today this has diversified into an era of innovative tools and technologies that are more inclined towards developing a new pool of applications. A pool that consists of different domains such as the Internet of Things (IoT), web of connected autonomous vehicles, remotely controlled robots, and heterogeneous sensors connected to serve versatile applications. 

In summary, there are now seven announced 5G devices categories; phones, hotspots, indoor and outdoor customer premises equipment, modules, Snap-On dongles and adapters, and USB terminals.

In addition, the 5G IoT chipset industry, as of April 2019 has four commercial 5G modem chipsets and one commercial processor / platform, with more expected to be launched in the near future.

5G Frequencies

As mentioned earlier, the air interface defined by 3GPP for 5G is known as New Radio (NR), and the specification is subdivided into two frequency bands; FR1 (below 6Ghz) and FR2 (mmWave). Both have different capabilities.

The maximum channel bandwidth defined for FR1 is 100Mhz, due to the scarcity of continuous spectrum in this crowded frequency range. So the band most widely being used for 5G in this range is around 3.5Ghz. For comparison, the Korean carriers use 3.5Ghz, although some millimetre wave spectrum has also been allocated.

The minimum channel bandwidth defined for FR2 is 50Mhz and maximum is 400Mhz, using two channel aggregation supported in the 3GPP Release 15. In the U.S. Verizon uses 28Ghz and A&T uses 39Ghz, although 5G is technically capable of using frequencies of up to 300Ghz, in other words, the higher the frequency, the greater the ability to support high data transfer speeds without causing interference with other wireless signals.

As a result, 5G can support approximately 1,000 more devices per metre than 4G.

Since 5G is capable of using higher frequencies than 4G, then the result is that some 5G signals will not be capable of  travelling large distances (over a few hundred metres). As a result, this does mean that 5G base stations need to be placed every hundred metres in order to utilise the higher frequency bands. The 5G signals also cannot easily penetrate through solid objects such as cars, trees and walls. This is mainly due to the nature of the higher frequency electromagnetic waves.

5G Infrastructure

5G incorporates Massive MIMO (multiple input and multiple output) antennas in order to increase sector throughput and capacity density. This uses a large number of antennas and Multi-user MIMO (MU-MIMO) in which each antenna is individually-controlled and may include embed radio transceiver components.

For reference, in over 562 separate 5G demonstrations, tests or trials globally of 5G technologies, at least 94 of them have involved testing Massive MIMO.

In addition, Edge computing is used in 5G, a technology that is delivered by cloud computing servers which since they are  geographically closer to the user, they reduce latency and data traffic congestion.

In the licensed and unlicensed spectrums, small cells, which are low powered cellular radio access nodes, are implemented to resolve the limitation of distance when using 5G’s higher frequencies. As small cells of have a range of 10 metres to a few kilometres, multiple small cells are required to provide 5G coverage over a large distance. 

As mentioned briefly before, beamforming is a technology that is used to direct radio waves to a target, more specifically, this  is achieved by combining elements in an antenna array so that the signals at particular angles experience constructive interference whilst others experience destructive interference. As a result, signal quality and transfer speeds are increased.