If you've ever scoped an indoor cellular project, you've probably heard the same answer: you need a DAS — a Distributed Antenna System. Bids come in at hundreds of thousands of dollars. The deployment timeline is measured in quarters. Construction crews need access to ceiling space, riser closets, and rooftop equipment rooms.

For some buildings, that's the right answer. For most buildings, it isn't — and we've been recommending the wrong solution by default for a decade.

What DAS actually does

A Distributed Antenna System is exactly what it sounds like: a network of small antennas distributed throughout a building, all fed by a central "head-end" that connects to carrier signal sources. The antennas re-broadcast cellular signal so that every corner of the building gets coverage.

DAS was designed in the 1990s to solve a specific problem: how do you provide cell coverage in venues where standard outdoor towers couldn't penetrate the structure? Stadiums. Convention centers. Subway tunnels. Large hospital campuses. Skyscrapers above the 30th floor. Buildings with metal facades or deep underground levels.

For those buildings, DAS is still the right answer. The signal has to come from somewhere, and dense antenna distribution is genuinely the way to do it.

Why the same tool got used for everything else

Two reasons.

First, until very recently, DAS was the only mature option. If a CIO walked into a meeting and said "I need indoor cellular in our warehouse / hospital / retail HQ," every vendor in the room had exactly one playbook to sell: design a DAS, build a DAS, install a DAS. The hammer met the nail it was designed for, but also met every other thing it could hit.

Second, DAS is profitable for the people who sell and install it. A typical DAS project pays for engineering, hardware, installation, carrier integration, and ongoing support. The economic incentive is to keep recommending DAS regardless of whether it's the right fit.

The problem with using DAS for normal buildings

For a 200,000-square-foot warehouse or a five-story medical office building, DAS is wildly oversized for the actual problem:

  • Cost. A DAS deployment typically runs $4-12 per square foot, putting most enterprise deployments in the $500K-$2M range. That's capital expense for what should be operational expense.
  • Time. DAS projects are measured in quarters, not weeks. Design, carrier negotiation, permitting, construction, testing, commissioning. A typical project from "yes, we need this" to "it works" is 9-18 months.
  • Operational disruption. DAS installation means crews working in ceilings, drilling through walls, pulling cable through riser shafts. In active healthcare facilities or operating warehouses, this is genuinely painful.
  • Vendor lock-in. Once you've installed DAS hardware, you're committed to that vendor's equipment for the asset's lifetime. Migrations are expensive and rare.
  • Capacity overprovisioning. DAS was designed for venues where 80,000 people might use cellular simultaneously. In a 300-person office, the capacity is dramatically more than needed.

What changed

The technical breakthrough is that software-defined cellular systems can now deliver carrier-grade indoor coverage by piggybacking on the Wi-Fi infrastructure a building already has. The access points become small cell radios. The existing cabling carries the signal. The head-end is in the cloud, not in a closet.

This isn't a replacement for DAS in venues where DAS is the right answer. It's a category-appropriate solution for the much larger set of buildings that have an indoor cellular problem but don't have a stadium's coverage requirements.

How to know which one you actually need

A few honest questions worth asking before scoping an indoor cellular project:

  • Do you have more than 5,000 simultaneous cellular users at peak? If yes, DAS makes sense. If no, you're probably overpaying.
  • Is your building genuinely RF-hostile (deep underground, metal-clad, high-rise above the 30th floor)? If yes, DAS. If no, software-defined options are likely viable.
  • Is the timeline 9+ months acceptable? If you need coverage in 60 days, DAS isn't going to work.
  • Is the capital cost acceptable, or do you need this as an operating expense? DAS is a capital project. Software-defined cellular is typically subscription-based.

For most buildings, the answers point away from DAS. The category just hadn't had a better option until very recently — and the new option is good enough that DAS-by-default is no longer the right starting point.