What exactly is 6G and how much of a leap forward would it be?

4 Dec 2019

CWI’s recently refurbished anechoic chamber, designed to completely absorb reflections of electromagnetic waves. Image: CWI/QUB

Prof Simon Cotton, director for the Centre for Wireless Innovation in Belfast, is part of a team already looking beyond 5G into the world of 6G.

While some network providers are claiming that there is ‘no demand’ yet for 5G among consumers, elsewhere the rate of 5G adoption is increasing. However, research claims that it will not be until 2025 when the internet standard really starts making a real impression.

And yet, 5G is not the limit of where the technology can go, with some already looking ahead to 6G. One group looking at the concept in great depth is the Centre for Wireless Innovation (CWI), based at Queen’s University Belfast. Founded in 2016, the centre has rapidly gained international recognition as a leader in the area of physical layer wireless technologies.

In the space of three years, it has moved in the Academic Ranking of World Universities’ global ranking for telecom engineering from 150th to 28th. Siliconrepublic.com caught up with CWI’s director, Prof Simon Cotton, to find out more about its work.

Prof Simon Cotton in a black suit, white shirt and wine coloured tie beside an event sign.

Prof Simon Cotton, director of the CWI. Image: CWI/QUB

What are the key focuses of the CWI?

Working primarily in RF [radio frequency] through to sub-millimetre wave bands, we are creating technologies that will meet the future requirements of users; whether it be coverage, data rate, latency, connectivity on a massive scale or wireless imaging and sensing – irrespective of operating mode and environment.

This includes award-winning research on wireless sensors, designed to be worn by or implanted into humans; low cost millimetre-wave antenna arrays for next-gen cellular base stations; and entirely new network concepts such as cell-free massive MIMO.

Looking towards the future and our evolution, we will continue to seek out opportunities to work across disciplines, not only to help others solve the challenges they face, but also to learn how their research tools and methodologies can be employed to advance state-of-the-art technology in the wireless space.

For example, like many others, we are very excited about the role that technologies such as AI and machine learning will play in our research. We have already successfully applied a number of these tools to create wireless systems that can identify their users and operating mode.

Not only does this open the door for added levels of security, but also the ability to schedule the delivery of hardware and network resources before they are even requested – a fascinating proposition indeed.

What makes 5G at frequencies above 20GHz so important to smart cities?

The millimetre wave frequency band will provide massive connectivity to cellular users – both humans and machines – with very high bandwidth compared to that offered in 4G networks or early-stage 5G, below 6GHz.

With the concept of massive MIMO, the possibility to beam the bandwidth narrowly and precisely to each end-user is there, instead of scattering it everywhere within a cell.

What exactly is 6G and how much of a leap forward would it be?

This is the overall term for future mobile networks to deploy in the decade after 2030, following 5G. It is still very early days. New concepts are taking shape and new theories are being discussed among communication scientists to offer even more bandwidth and less latency than in 5G networks.

One of those concepts is called cell-free massive MIMO. The researchers at CWI are leading the thinking on this, whereby mobile networks will not rely on cells for their configuration and topology, but on millions of smaller devices – called access points – about the size of a Wi-Fi router. There are, however, years of computation, probabilistic modelling and experimentation needed to develop the concept that can work in the real world. Frequency bands used in 6G will most probably be those beyond 90 GHz.

How much does security play into your work at CWI?

Our researchers focus on physical layer security, using directional modulation techniques to scan the communications channel – or layer – in the telecoms stack, all while encrypting and decrypting the signals each time they are transmitted down to a single user.

Even quantum computers may struggle to break in, in real time. Each encryption being produced is used only once and refreshed the next time it is needed. It offers the highest level of security for wireless communications, which is essential to prevent intrusions or attacks on critical applications like autonomous connected vehicles, IoT devices in critical national infrastructure or even smart homes.

How does your work influence the future of global satellite broadband networks?

Orbital broadband networks will need large constellations of small satellites to relay transmissions effectively and at lower power consumption than today’s larger satellites.

This is where our technologies of wireless transmission absorption and refraction – known as frequency selective surfaces (FSS) – come to play a major role in increasing efficiency over any previous satellite wireless technology.

FSS are used in Earth observation satellites to separate signals, which are collected by single reflector antennas. For these, FSS provide broadband remote sensing capability by enabling the instrument to work over a large frequency bandwidth.

So, one instrument replaces many that were required in the past, thus reducing the footprint of each satellite (useful for nanosatellites) or [packing] more equipment onto a larger platform. FSS are an optimal solution to be used for future satellite broadband communications systems.

Colm Gorey was a senior journalist with Silicon Republic