InterDigital’s Head of Future Wireless Dr Alain Mourad discusses the fifth generation (‘5G’) cellular technology network standard and why we’re already thinking about 6G and beyond.

Checking the digital cartography app on my smartphone just outside London’s Old Street tube station, I can see that my device is flicking intermittently between 3G and 4G. This is not particularly helpful in getting Google Maps to help me navigate on foot around Old Street’s notoriously complex pedestrian junction. It’s also embarrassing, because I’m running late for my appointment with one of the world’s leading experts on mobile cellular technology network standards, InterDigital’s Head of Future Wireless Dr Alain Mourad.

Thought leader, inventor and holder of more than 50 patents in this technology space, he’s making time to bring me up to speed on the fifth generation (‘5G’) of the standard, 6G and maybe beyond. With my smartphone barely able to make a phone call, it’s not a good omen.

When I eventually locate InterDigital’s HQ in London’s Covid-19 ghost town, we sit in the conference room of an otherwise deserted office suite and we jump straight in. I ask the Anglo-French technologist why on earth, when 4G appears to be barely functioning in one of the great capital cities in the world, are we talking about 5G, let alone its successors.

“It’s a great question actually,” says Mourad, and it transpires, a timely one too. This is because, when the public thinks in terms of such phone network generations, “what they’re really thinking about are marketing terminology, not the technology.” He explains that the status of 5G as a consumer product is distinctly more prosaic than where the TV adverts marketing 5G-ready electronic devices would optimistically have us believe. “Essentially, where we are now is simply a reflection of the fact that at the beginning of 2021, we had the International Telecommunication Union (ITU) approving what we call IMT-2020,” which is, put simply, a list of requirements for developers of 5G networks, devices and services.

Mourad is keen to point out that “this approval doesn’t necessarily mean that the 5G service is available to us as end users”. What it means is “we have the most important global body – the ITU – saying which specifications are meeting the requirements that have been set by IMT-2020 for 5G as far back as 2012, 2013.” It follows that the end user will not necessarily see these specifications manifesting themselves as a commercially deployed service – “if you like, the 5G solution” – for some time. “Typically, there is a lag of two or three years from when a specification is completed, and rubber stamped” to when the technology appears on our devices.

When you see the ‘5G’ tag at the top of your phone screen, “this is a commercial and marketing thing, rather than an indication of the presence of the technology recommended by the ITU. If I want to talk formally or neutrally about these systems as a technologist, I refer to IMT-2020 for 5G and IMT-2030 for 6G.” It’s also important, he adds, not to confuse cellular network nomenclature with WiFi terminology: “we already have WiFi 6 and that’s their own thing. When we talk about 2G, 3G, 4G, 5G and now 6G, this is specifically about the mobile cellular telecommunication systems.”

Mourad says that the successive cellular network generations are part of a cycle that “starts with a vision, which is very much centred on what we think we can expect in the next five to ten years.” To reach a new generation, there are five phases in the cycle overseen by the ITU that can typically span a decade: vision; requirement; specification; evaluation; and recommendation. What we call the ‘generation’ manifests itself tangibly as a series of documents published by the ITU. “All stakeholders, such as wireless systems developers, feed into these documents; they feed into the vision that will conclude with a report that reaches a consensus from literally hundreds of organisations that this is where the agreements are.

“This is essentially a timeline on which we try to say which services we can anticipate and forecast as becoming mainstream in society. Then we look at what these services require in terms of technical performance within the system so that the desired benefits can be delivered.” Mourad explains that the vision then changes into a list of requirements, at which point, “the ITU works closely with standards development organisations such as the IEEE, to ensure that this is all achievable in the time horizon laid out for that generation.” At the same time, requirements are established at a level of ambition consistent with elevation “to a new generation. It can’t just be incremental. It has to be something major or drastic, such as a significant improvement in services.”

4G was all about speed, whereas 5G is more about latency and a smoother experience.

The best way to think of this, says Mourad, pointing to a graphic of the future progress from 5G to 6G projected on to the conference room wall, is to envisage a new generation arriving when we pass an inflection point, “which is a step change. In this case, it is a step change in requirements. We already have 5G (because of IMT-2020). But we’re not going straight to 6G. What the standards development people are working on is an advancement of 5G, which even has a logo and marketing name: 5G Advanced.” The reason 5G advanced is called just that (and not 6G or even 7G) is “because the advancement is backward compatible with what has already been specified. It could be something like a 20 per cent performance increase for any KPI. But you couldn’t have a significant departure – such as 1,000 times performance increase – within the constraints of backward compatibility.” The technology required to advance to a new generation usually doesn’t exist within the framework of older iterations, while the breakthroughs introduced to make step changes are what helps bring “a new generation into the light”.

The evolution of a mobile cellular network generation – from vision to commercial implementation – will inevitably bring with it a multitude of stakeholders “beyond just Nokia, Ericsson, BT, AT&T, Samsung or even InterDigital. There aren’t just the technology companies, operators, vendors, service providers. There are governments and regulators: these are key stakeholders because generations typically come with their own spectrum, which is a significant contribution to government budget when it comes to auctioning the spectrum. Then there is the telecom infrastructure, which is a big deal, especially the digital construction that we rely upon for all our services. Yet the stakeholders are much wider than that: you could claim today that the whole of society is the main stakeholder.”

At this point, Mourad shifts his focus to the players who are putting together the mobile cellular network technology landscape on the global stage. As tempting as it may be to see this as similar to software product development, “where companies write it in-house and then release, it is in fact the product of many, many companies, institutes, regulators all coming together to define a generation with all its parameters. The fact that the ITU has ownership of the process from the very beginning all the way through to saying that this is officially what we can call, say, ‘IMT-2020’ or ‘IMT-2030’ shows how important it is as a global process, and how it is the result of reaching consensus among stakeholders. This is important, because after 2G, from 3G onwards and hopefully into the future, we really are talking about something that is not American, or Asian, or European, but a global collaboration on a global system. Therefore, when you go somewhere like the States, you don’t need to change phone or have to worry about the compatibility of your phone services.”

In demonstrating the global nature and diversity of the cast-list of stakeholders, Mourad is essentially showing how contributions to 5G and 6G from companies such as InterDigital – a NASDAQ-listed multinational technology R&D organisation – represent just fractions of an ecosystem of almost unimaginable scale. He explains that InterDigital “plays at the beginning of the process of developing a new generation. When I say, ‘at the beginning’, I mean even before the ITU officially starts talking about defining a global vision. We’re an R&D company, so we come at this two, three, four years ahead the start of the process.

“We will be already looking at what that vision might be and are ready from a technology development point of view to feed into the requirements. We are also there to support the evolution of the generation. Before we get to 6G, there is also 5G Advanced to consider.” What this means for Mourad is that InterDigital is “always working on two tracks: one that goes to evolving a generation, and then something more disruptive that will come further down the line.”

This sort of horizon scanning is a fixture of Mourad’s thinking. It’s all about the future. It doesn’t matter what marketing people say, 5G isn’t here yet in the sense of it being a fully deployed commercial reality for the consumer. “5G will hopefully be here in 2023 and that’s when we’ll start to see proper 5G service, implementing the full package of IMT-2020. In user terms, this will mean that we’ll start to see a downstream data rate of about 100MB/s, which is quite significant.”

This increased speed will bring functionality such as augmented reality gaming to the smartphone. “But it’s not going to be just about speed,” says Mourad. “It’s also about delay or latency. 4G was all about speed because the killer application was video. But with 5G there’s no such consideration, and if you like, the promise of 5G hasn’t been fulfilled yet. However, what’s interesting is that in parallel to concerns about speed there is a concentration on latency.”

Mourad thinks that with 4G, there’s plenty of speed for video but when it comes to gaming (or even, trying to find the InterDigital offices on a real-time navigation app) “the delay is another dimension of speed that 5G is going to address. So, for the end user, the experience of controlling devices such as drones will benefit significantly from a proper 5G service by 2023. For the consumer, it will feel as though it works much better.” If tech-literate consumers want to, says Mourad, they can do a speed test and satisfy themselves that the data rate is far higher than on 4G. But the real uplift in experience will derive from the fact that a whole range of applications will simply run smoother due to improvements 5G brings with it, in terms of the time it takes for data to cross the network and arrive at its destination.

As mobile cellular technology communications standards are numbered with positive integers rising in increments of one, it is only natural to suppose the series will run into the distant future with new generations emerging at intervals like those we’re already familiar with. Companies such as InterDigital that are busily working on 5G, are also actively preparing for 6G and presumably have more than an eye on 7G. Mourad confirms this, although as with all matters related to cellular network generations “it’s not that simple. Yes, there is a step-change from one generation to the next. But each generation builds on top of the generation that has gone before.”

He says a good analogy to explain how each level comes together is that of a funnel. “At InterDigital we start at the top of the funnel, where there are a lot of promising technologies that could have an impact on 5G.” He demonstrates with his hands how these technologies circulate around the widest part of the funnel’s circumference. “Some of these technologies will come into the mainstream, which is where they get specified into the standard and eventually make their way into the product.”

Meanwhile, there are the residual technologies that didn’t quite make it into the standard still swirling around. “Does that mean we stop thinking about them and do nothing to develop them?” The strong possibility is that some, after further development and assessment, will find themselves entering the mainstream of a subsequent generation “as they evolve and as gaps are fixed. Maybe these ideas need some time to mature and will be more suited for inclusion in the next generation.”

When pushed for a definitive answer on whether InterDigital has started to work on 7G, Mourad thinks this is by default the case. “My expectation is that some of the technologies that will find their way into that generation are incubating today. Inevitably, some of what we’re working on will get into 6G and some won’t. But they will be re-incubated and matured to go into 7G. I don’t think we shouldn’t think of these generations as separate and decoupled.”

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