In short: The REACH project deployed cell-free massive MIMO technology across sites in Blackpool, rural Yorkshire, and Lincolnshire, then validated more than 50 emergency calls on a private 5G network in Buttermere -- a Cumbrian valley with no commercial mobile coverage at all. The project also demonstrated AI-driven xApps that dynamically reduce radio network energy consumption.
Key Takeaways
- 50+ emergency calls validated in a total not-spot — Buttermere in the Lake District has zero commercial coverage; REACH proved that a private 5G network can reliably carry emergency calls where no operator serves
- Cell-free massive MIMO extends coverage without multiplying sites — distributed antenna elements provide uniform coverage across difficult terrain, reducing the number of mast installations needed
- AI-driven xApps cut network energy consumption — machine-learning applications on the O-RAN RIC dynamically adjust radio parameters to save power during low-traffic periods
In a nutshell
The Buttermere Problem
Buttermere is a valley in the western Lake District, surrounded by fells rising steeply on all sides — beautiful, remote, and popular with walkers and climbers who routinely venture into terrain where a slip or a weather change can become a medical emergency. It has no commercial mobile coverage whatsoever: not a single bar from any UK operator. When someone is injured here, getting help means walking to a farmhouse with a landline or hoping someone notices you are overdue, and mountain rescue teams cannot communicate by phone. We raise this not as an abstract policy concern but because it is, at time of writing, a situation where people can and do die for want of a signal.
The REACH Consortium
REACH was funded under DSIT's Open Networks Ecosystem Competition, the same programme that supported Aerix's ONE WORD project — at GBP 10 million the largest funded effort in the competition. The University of York led the consortium alongside Cybermoor 5G Services (a Cumbrian community interest company), Quickline Communications, VMO2, and Viavi Solutions.
Cell-Free Massive MIMO
Instead of concentrating antenna elements at a single mast, cell-free massive MIMO distributes many smaller antenna units across the coverage area, all connected to shared processing — the elements cooperate coherently, serving each user from whichever units have the best path. There are no cell boundaries or conventional handovers, and coverage is far more uniform across difficult terrain.
For Buttermere, antenna elements placed at accessible points around the valley rim can collectively serve the entire valley floor and surrounding fellsides without a dominant mast in the valley itself. The approach is notably more sympathetic to the National Park landscape and more effective at filling the coverage gaps that defeat conventional architectures. The trade-off is that distributed antenna elements require backhaul connections to each unit, which adds deployment complexity in terrain where even running a cable can be challenging — but the alternative of building a large conventional mast in a National Park is both visually intrusive and likely to face planning objections.
Fifty Emergency Calls
The headline validation: more than 50 emergency calls were successfully originated and completed on the private 5G network, each testing the full end-to-end chain — handset, air interface, network, and emergency call handling. In a location with zero commercial coverage, each call represents a scenario where someone in distress would otherwise have no way to summon help by phone.
The validation confirmed that the network meets technical requirements for emergency voice: call setup time, audio quality, reliability, and location reporting. Crucially, cell-free massive MIMO provides sufficient coverage consistency for calls from the places where emergencies actually happen — on the fells, by the water, on the paths. We find this the most compelling single result to come out of the entire Open Networks Ecosystem Competition programme.
AI-Driven Energy Savings
REACH also demonstrated AI-driven xApps on the O-RAN RIC that dynamically reduce energy consumption, and this is an important practical detail that is easy to overlook. A rural private network serves highly variable traffic — some activity during the day from walkers, near-silence at night — and the xApps scale back transmit power, active antenna elements, and carrier activation during quiet periods, maintaining emergency capability whilst drawing a fraction of peak power. For a solar-powered or generator-backed site, this is the difference between sustainability and draining the power budget before the week is out.
From Buttermere to Everywhere
The pattern REACH establishes — cell-free massive MIMO for terrain-sympathetic coverage, Open RAN for vendor flexibility, AI-driven energy management for sustainability — applies to hundreds of similar locations across the UK. The Open Networks Ecosystem Competition was designed to generate exactly this evidence: real deployments, in real locations, with reusable architectures. If a private 5G network can carry emergency calls from the floor of Buttermere, the argument that rural coverage is too hard looks considerably weaker, and we believe the remaining barriers are primarily commercial and regulatory rather than technical.
If you need to bring connectivity to a rural area with no existing coverage, get in touch. Read more about our rural deployments and the ONE WORD project on our about page.