If the telecom industry is at a crossroads looking for a means to navigate a path to renewed relevance and revenues, the tower space is stuck on the Magic Roundabout – the most complex round in England, in which five mini-roundabouts encircle a central island.

The tower space’s traditional model lends itself to an ultra‑conservative, long‑term, low‑change idea, where 20‑year rental agreements provide comfort. But beyond that slow, asset-heavy mindset is an increasing desire from tower companies for more: more growth, more revenue streams, and –most importantly – more relevance.

Crown Castle’s decision to sell its fiber and small cell businesses for a staggering $8.5 billion to focus on becoming a pure-play tower operator shows that maximizing value from a frankly high-margin, predictable business that’s only set to benefit from buildouts like 5G network densification means there’s still some life in the old girl yet.

But for many it’s not enough. Their carrier brethren are striding confidently toward new means to line their coffers through everything from GPU-as-a-service to sovereignty solutions. And tower companies want in.

Case in point: Cornerstone, the U.K. tower company that is working to deploy micro-edge compute capabilities on its sites.

Cornerstone is working with StonesThro, a specialist digital infrastructure-focused consultancy and solutions provider, to turn existing mobile tower sites into mini data centers by adding ruggedized cabinets housing GPUs on‑site and networking them together.

“We're taking high-performance, high-grade GPUs, taking them out of a temperature and humidity-controlled data center, and putting them in a box in a field, which comes with its own challenges,” StonesThro CEO Ashley Sellar explained to SDxCentral.

The idea of bringing edge computing to the tower is nothing new, of course, with tower company leaders having pushed the concept for several years. SBA Communications, for example, were exploring placing edge modules at tower sites in 2018 in a partnership with the bare-metal firm Packet before the latter’s acquisition by Equinix.

The reality, though, is that practical implementation has been lacking.

“A lot of people have danced around the edges of this,” Sellar said, adding that the failure of multi-access edge computing (MEC) to take off has resulted in tower companies and operators becoming wary of the idea of compute at the edge.

But while the concept’s precursor failed to deliver on its early hype and subsequently left the industry cautious, Cornerstone and StonesThro are positioning their live micro‑edge deployments as a means to prove real, revenue‑backed use cases and overcome that skepticism.

“We are starting to see some technology evolution that is going to be more insistent around having edge data center capability, and that's driven by volumes of content and also low-latency processing,” Sellar said.

“[Tower companies] are starting to be inquisitive about it," Sellar added. "There’s an opportunity for them to dip a toe in the water and really test that, but they want to see somebody go first. So that's what we're trying to do.”

The first plunge: Concepts in the field

As already established, the idea of playing it safe and sitting tight is synonymous with the tower industry.

But given Sellar and the teams at Cornerstone and StonesThro are taking the first plunge, their initial play seems to have one eye on a potentially lucrative prize.

Global spending on edge computing solutions is projected to increase from nearly $261 billion in 2025, to $380 billion by 2028, according to IDC figures.

For the mobile edge computing market specifically, Mordor Intelligence suggests the space was valued at $800 million. Now, while that might seem quite low to many in the technology space, the market is still in its salad days, with Mordor Intelligence projecting the market to reach $3.88 billion by 2031.

Again, seems quite small when compared to the tens-of-billions-of-dollars being talked about in the general edge data center market, like $71.9 billion in 2035 according to Global Market Insights.

But as Sellar said, the micro data center-tower colocation model needs that initial spark, and those market projections could very well find themselves looking a wee bit off kilter.

Speaking ahead of Mobile World Congress, Sellar revealed that a handful of operators are keen to speak to them to find out about their efforts, adding: “Some people [are] really quite inquisitive, but they want to see the commercialization and use cases.”

Sellar and the team will then be able to talk about actual use cases in action, with a total of three sites already in place in Milton Keynes, Southampton, and Solihull. Those initial sites are focusing on workloads for AI inference, video analytics, and other latency‑sensitive or sovereignty‑driven applications that benefit from distributed infrastructure.

“There are a few reasons we built three,” Sellar said. “We want to be able to federate those sites together so we can manipulate workloads because, ultimately, we're building a mesh. But also, we wanted to try different designs and a different configuration. So, for instance, the one in Southampton has high-performance Nvidia GPUs in it. We know that's going to generate a lot of heat and run those GPUs up to around 149 degrees Fahrenheit (65 degrees Celsius) with no problems, and managed to keep the cabinet temperature stable.”

The initial deployments have also focused on trying out different types of cabinets, including forced air, single air conditioning, and dual air conditioning to allow the team behind the projects to monitor the hardware inside to see how these environments perform.

The choice of site location was also a key factor in showcasing the concept’s true potential. Milton Keynes, despite its reputation as a dull, concrete jungle, is in fact the country’s leading smart city, acting as a hub for trialing delivery robots and driverless cars.

Meanwhile, Solihull sits at the heart of the national road network, while Southampton is home to one of the busiest passenger and cargo ports in the country.

And while the Cornerstone/StonesThro team has those initial deployments off the ground, so to speak, the Sellar said future scale-up will look beyond the South of England to potential tower sites further north.

Security & staffing

From the potential to the practical, there are some genuine hurdles to overcome if the tower space is to make this work.

The first is around security. In the wake of the pandemic, cell towers are increasingly subject to arson and vandalism from victims of misinformation. But there’s also the threat of thieves. And if there’s something opportunistic bandits are going to want to get their hands on, it's cabinets filled with high-end GPUs worth thousands of dollars.

To avoid giving thieves such a potential Christmas present, Sellar said Cornerstone and StonesThro are opting for “security through obscurity” to keep their kit safe.

“You wouldn't notice the difference," Sellar said. "In fact, we'd love to have branding on the side that says StonesThro edge data center; however, that would alert the bad guys to the fact that it's not just another gray box that looks like every other gray box you see at the side of the street.”

But a more fortified approach sees the team employ perimeter fences actively monitored by closed-circuit TV (CCTV) with proximity detection.

“Part of our specification is that it has to have a steel palisade fence around, we have electronic and remotely controlled access controls so that they work on a token basis, so we can control which engineers go at what time to the site,” Sellar said. “We've deliberately picked sites with mobile operators that aren’t at street level, reducing the risk of road traffic accidents where somebody might drive a double-decker bus over the top of the site.”

Though their efforts may just work a bit too well.

“One of our guys once went up to change a cable and forgot to inform them and he got within 10 meters of the site and was immediately loud-hailed, 'what are you doing around our site?' So we know that works," Sellar said.

Beyond physical protection, there’s also logical protection at play, with everything encrypted at rest, while processes are paired directly to that site so if someone were to take something, they can’t reuse any of it.

Compounding the concerns around security are the ideas off staffing, which Sellar likened to “smashing two worlds together.”

On the one hand, there are the traditional telecom engineers who are used to going up towers, fixing dishes, and know their environment well, but have next to no idea what to do with a high-end GPU or managing scale-up connectivity. And then there’s the data center engineer used to the whirrs of fans cooling inside a cushy data center. Are they really going to want to trudge out to the middle of a muddy field to fix just one cabinet?

Even something as simple as terminology use can cause consternation.

“If you talk to somebody in infrastructure and you say, 'PaaS,' okay, yeah, it's power-as-a-service, versus somebody in cloud that says that [is] platform-as-a-service, two very different things,” Sellar said. “You can see these conversations happening where people are talking for 15 minutes about something that's completely different because they've used the same terminology and they don't realize until somebody says, 'how's that going to work?' And then they realize been talking about different things.”

Cornerstone’s deployments with StonesThro have used telecom engineers for physical aspects, like landing cabinets, connectivity of power, wireless, and fixed network, and any metering and cooling aspects. The only real major difference is the physical configuration inside the cabinet.

But for data center engineers working to bring those edge compute cabinets online, there’s even a need to reconceptualize around health and safety certifications.

“If you're sending somebody onto a tower site, you probably want them to, depending on the scope of work they're undertaking, to have a climbing up heights certification. You don't need that for somebody going to go into a data center to plug in a box," Sellar said.

“Personal protective equipment (PPE) that they wear in a data center is a wristband with an Earth strap on it. You go into a field site, you need steel capped boosts, high-vis, helmets, etc.," Sellar added. "So we're implementing things like health and safety aspects with data center-trained engineers so they don't have to upskill, but it's the health and safety, it's not the technical aspects.”

That focus on re-examining the environment engineers work in rather than trying to re-invent the wheel and retrain an entire workforce forms a kind of blending of both worlds that Sellar and the team hope will ensure its edge projects will get off the ground and run even faster.

From testbed to reality

For Sellar and the teams at Cornerstone and StonesThro, getting hardware into the field is only the first half of the experiment. The real objective is to turn Cornerstone’s sites into a living testbed for would‑be edge users, and, in doing so, giving the wider tower sector the proof it has been sorely waiting for.

“We want people to come and use it. We want to really give the tires a good kick on the platform,” she said, noting that prospective customers can already join a waitlist to run proof‑of‑concept workloads on the three live sites.

If those early trials show that tower‑side micro data centers can do what many in this sector have longed for, then those operators may just start queuing up conversations beyond MWC.

“We plan to come out of that proof‑of‑concept stage at the end of March,” Sellar said. “What we’re really keen to do now is show that this is a thing.

“We've had some great feedback, both technically and commercially. We've had a big tick in the box technically, we know that we need to be at parity or a similar level to the hyperscalers price-wise," Sellar added. "We're still benchmarking, but the early signs are that cost effectiveness, because of the way that our charging model works, we don't have some of the charges, like egress charges for data, number of IOPs, etc. So the price that you see is really the price that you pay.”