By Simon Frumkin, CEO at connectivity infrastructure-as-a-service provider Freshwave
Imagine running a system that consumes 65 watts of power, generates enough heat to require cooling, and then delivers less than 1 watt of useful output. In most industries, that would raise serious questions about efficiency. Yet this is effectively how many indoor distributed antenna systems (DAS) operate. Large amounts of energy are consumed generating, distributing and managing RF signals, and then cooling the equipment in the main equipment room; only a small proportion of this energy ultimately reaches the antennas that provide coverage to users.
DAS was invented in the 1980s partly to reduce transmit power by moving antennas closer to users. Ironically, modern DAS deployments can now be criticised for their overall electrical power consumption. Technology has continued to evolve though, and small cells are now a viable alternative for many organisations looking to bring assured all-operator connectivity indoors.
Where once a separate small cell box per operator was needed, it’s now possible to cover all UK mobile network operators via a single combined unit. The result: lower energy use, lower installation costs, quicker deployment, and less space needed in the comms room.
Why do we need in-building mobile systems?
The MNOs have invested billions in their outdoor networks so we can use our phones when out and about. But building materials – low-e glass, concrete, steel – often block that signal the moment people move inside.
Most of us are essentially attached to our mobile devices, so any disruption is quickly felt. And it has real financial consequences. Our Mobile Connectivity ROI Index 2025 found that just five minutes of poor connectivity a day reduces annual productive time by 1% – and that poor connectivity costs the UK economy £100 billion a year.
Mobile devices are now essential for productive work – from calls with clients and colleagues to multi-factor authentication codes. And as organisations have shifted towards bring-your-own-device policies, a single-operator indoor solution simply isn’t good enough. Everyone needs to be covered, regardless of which network they’re on.
Who pays for in-building mobile systems?
As MNO budgets become increasingly constrained, investment gravitates towards a small handful of the largest and busiest venues, leaving many buildings struggling to secure coverage funding. At the same time, building owners are increasingly treating strong multi-operator coverage as essential for their tenants. As the leading provider of the enterprise-pays model of indoor connectivity, we deliver mobile connectivity as a managed service for a monthly recurring fee.
Freshwave’s Omni Network is a neutral-host solution that connects all UK mobile network operators from a single small cell unit – and it does so at significantly lower cost and energy use than traditional DAS or even earlier small cell approaches. Organisations like Grant Thornton, GSK and Workspace have already deployed it, with sustainability a key driver.
Where does all that power go?
Let’s get specific about the numbers, because I think they’ll surprise you.
A typical all-operator DAS system amplifies signal at 65 watts. By the time that signal passes through the attenuators and distribution components needed to manage multi-operator output, just 0.8 watts of useful power reaches the antennas – around 1% of what went in. The other 64.2 watts is dumped as heat. That heat then needs to be removed, requiring cooling equipment that adds further energy demand on top.
Add it all up and you’re looking at approximately 110,000 kWh of energy wasted per year, per DAS. At current electricity prices, that’s around £27,000 a year – gone, regardless of which DAS vendor or design you choose. This isn’t a flaw in a particular product. It’s a fundamental limitation of the DAS architecture itself.
The Omni small cell approach works differently. Rather than generating high power centrally and then attenuating it back down, small cells produce low power directly at the point of need. There’s no signal to dump, no heat to manage at the same scale. Compared with a leading digital DAS, our Omni Network delivers at least 60% lower energy consumption – and that gap is consistent whether you’re covering a four-sector or a six-sector building.
To put it in concrete terms: for a four-sector building, annual energy costs for Omni come in at around £8,900, versus £33,000 for a comparable DAS deployment. For a six-sector building, Omni costs around £17,000 per year versus £61,000 for digital DAS. That’s a saving that makes a material difference to building operating costs – and to a sustainability strategy.
The right solution for the next decade.
There’s a broader point here. Sustainability requirements for commercial real estate are tightening. Building owners and occupiers are under pressure to reduce their Scope 1 and 2 emissions and demonstrate progress on energy efficiency. A connectivity infrastructure decision that locks in 110,000 kWh of wasted energy per year is increasingly hard to justify – especially when a better alternative exists.
The good news is that better connectivity and lower energy consumption are no longer a trade-off. With small cell technology, you get assured indoor coverage for all operators, faster deployment, less space in the comms room, and a significantly smaller energy footprint.
That’s not to say that DAS doesn’t have a place still, it does. For extremely high footfall environments, such as major transport hubs and very large stadiums, a DAS provides the necessary capacity to meet the demands of tens of thousands of people all using their devices at once. To put this into perspective, a large stadium can experience peak demand from 60,000 mobile devices during key moments such as halftime. By comparison, a typical 150,000 sq ft office building might only need to support around 1,000 simultaneous network connections at peak occupancy.
The question isn’t whether to address indoor mobile coverage; our ROI research makes clear that 87% of UK organisations say poor mobile connectivity causes daily disruptions at their sites. The real question is how. And the evidence increasingly points away from DAS architecture, with its fundamental efficiency constraints, towards small cell infrastructure that delivers better performance with a fraction of the energy footprint. The technology has caught up with the sustainability agenda. It’s time the industry’s deployment decisions did too.
Learn more: Freshwave
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