What is a 5G network?

Without fail, each and every day, I get asked “but what is 5G?”, so I collected my thoughts to provide this 5G  technology explanation. Unfortunately, it can sometimes be challenging to realign expectations and understanding on such a technical topic while riding even the longest elevator rides in the tallest buildings. There is, without doubt, more confusion than ever around the technological change currently taking place in the cellular ecosystem.

As an Engineer in the field I’m excited about what’s on the horizon and make no mistake there is a step-change in the wind. However, having been through similar transitions previously and understanding that we’ve traveled this road before, the reality is that network evolution of this magnitude will take time. There won’t be an instantaneous change in your experience overnight. For the most part, the general public is of the opinion that 5G mass adoption is imminent, promising gigabit speeds and expecting coverage to be widespread. Fair enough to them, if you follow the day to day media train and have limited technical understanding, you will no doubt be convinced it is at your fingertips today.

In a way the promises of capabilities to be enabled by 5G technology are true, but for the most part not straight away. To really understand the ‘state of play’ we need to delve into some technical topics first.

What is new with 5G?

5G is a term describing the next major evolution in cellular technology. 5G networks are a collection of technologies and enhancements on cellular networks using new spectrum and some smart maths to turn things up to 11. (This is normally the two sentences I can get out on that previously mentioned elevator ride). Fundamentally 5G is not dissimilar to 4G, it uses very similar radio technology and is more akin to evolution than a complete revolution.

At the end of this network evolution, we expect a few key features of 5G to come to fruition

• Increased data throughput speeds, >1Gbps is within the realm of possibility
• Low Latency <5ms to support autonomous vehicles and other use cases
• Number of simultaneous connect devices to increased 10x

I place the types of 5G into a few categories which work towards these features – Mid band 5G and True MM Wave 5G, but first, we need some overall context.

Up until now in Australia cellular services have been delivered over the 700-2700MHz frequency bands. There is a bit of international variety around bands but typically this range of bands is what commonly gets referred to as ‘sub 6GHz’ or Frequency Range (FR1). These bands have served as the primary frequency bands for the delivery of 2G through to 4G technologies, with spectrum often being ‘refarmed’ or reused along the way as we transition from old technologies to new.

The challenges however within these FR1 existing bands is that there isn’t a huge amount of spectrum available to use. Most 4G channels are made up of 20MHz channels which on a good day can deliver a solid 100MBps in ideal environments (which isn’t too shabby for most use cases by any standard!).

4.9G LTE Advanced Pro

While 4.9G isn’t an official name it is highly recognised in the industry as being a precursor to 5G and represents the most technologically advanced 4G network (of which I would argue there isn’t many). 4.9G is really a feature set which aims to maximise the spectral efficiency of the network with features including:

• Carrier Aggergation: The ability to combine multiple bands throughput together into 1 fat pipe. (5G improves this technology further)
• Higher order MIMO: Continuing to improve the throughput of the network through 4×4 MIMO and onwards
• 256 QAM: A higher modulation scheme allowing for devices to push more data throughput through the existing network
• Unlicensed spectrum: Operators can utilise unlicensed spectrum in conjunction with 4G such as the 2.4GHz and 5GHZ Wi-Fi bands.

A lot of the early ‘5G trials’ or Gigabit LTE which produced speeds in excess of 1+Gbps utilise technology that exists today (yet is still very limited in the networks themselves). Its worth nothing that with the technology we have available today its already possible to achieve such speeds pre 5G era. AT&T in the USA marketed this as 5Ge with the e standing for evolution, whilst it copped a lot of backlash realistically the maturity of LTE Advanced Pro networks will be the backbone of the majority of users 5G experience for some time (regardless of whether they have  4G or 5G symbol at the top of their phone)

Mid Band 5G

Most deployments (and all in Australia) of 5G today are being done over a combination of new frequency allocations and existing bands within the sub 6 GHZ range. The major Australian operators having recently completed their 3600MHz spectrum acquisitions are actively deploying 5G radio across this band and refarming existing frequencies (such as Telstra 850MHz plan) to underpin the rollout of 5G coverage. Mid band 5G will without a doubt be the primary 5G band the ‘average’ consumer can expect to see for a while. The current implementations are ‘Non Standalone’ which means they are intertwined with the 4G network as calls still remain on 4G and the 4G network provides carrier aggregation to increase overall throughput. The mid band 5G propagation and related signal penetration into houses and buildings particularly on the lower frequencies such as the 850MHz is viable for achieving widespread 5G coverage quickly. This strategy is not dissimilar to Sprint’s rapid deployment of their 600MHz 5G network in the USA, whilst its throughput is somewhat limited it has provided a large coverage footprint rapidly.

True 5G – mmWave

True 5G will meet the expectation of most in terms of performance, however, it is unlikely to be here within the anticipated timelines. It will be significantly faster allowing you to download a whole series of Netflix within minutes. But to achieve these speeds the radio has a few new requirements

• Large amounts of available bandwidth i.e. 100MHz per channel
• Massive MIMO creating linear multiples of throughput
• Beam steering allowing the smart integrated radio/antennas to intelligently track capacity demands

Implementing the above 5G technologies presents some challenges

• To find such large amounts of bandwidth we have to go into the higher bands in FR2 (6GHz-60GHz). Most countries are looking at frequencies such as 26GHz and upwards, often referred to as ‘mm Wave’. The important thing to note here is that ‘G’ which comes before the Hz… it used to be a M if you scroll back up to FR1. Essentially, we’ve gone up by a multiple of ten from the commonly used 2100MHz (2.1GHz) up to 20 odd GHz – a ten-fold increase in frequency that has a huge impact on the distance signals will travel (perhaps you are familiar with 2.4GHz Wi-Fi vs 5GHz Wi-Fi)
• With this newfound spectrum physics does however do us a favour and what would have been a 64×64 MIMO antenna in FR1 the size of a small car is now the size of an A3 piece of paper.

Suddenly FR2 and 5G come together to produce hugely fast speeds, but with a caveat that it doesn’t go very far. This means that in order to provide a continuous level of service we need to start installing infrastructure everywhere, lamp posts, fountains, parks, bus shelters etc. This is both a long process and a hugely expensive one. When your operator is already giving you ever-increasing data limits on your mobile plan (if not already unlimited) the business case to scale infrastructure across the entire network to this degree just doesn’t stack up.

In Australia what I call ‘True 5G’ has only really been seen in limited trials by Telstra. The mmWave bands are still yet to be auctioned by the ACMA, so nobody can really deploy any significant variants of True 5G even if they wanted to. Even if they could the economics will not stack up. For some time to come we can expect to only see this kind of deployment in very select high-density zones. For the bulk of deployments in the near future, we will see a simpler flavour of 5G in the midband.

Summary

Its easy to see why 5G Technology is causing so much confusion as its largely a collection of the current and future technologies coupled with available existing and yet to be released spectrum all bundled under one banner. We can expect to see an ongoing evolution from 4.9G -> Mid band 5G onwards to mmWave 5G, but it will be a journey rather than a lightbulb moment. The use cases and devices to support it are still developing in parallel in a somewhat chicken and egg scenario. There is still an enormous amount the industry can squeeze out of 4.9G to continuously improve the customer experience over and above what is provided today and into the 5G migration.

Wireless Coverage Solutions have been through the changes of technologies many times before, if you have any queries don’t hesitate to contact us to discuss further