Many years ago, I shared a basement apartment in Boston with a few college friends. Because we were "garden level” (partially underground), there was no cellphone service, so we relied on WiFi for calls. It worked well until you had to leave the unit. The moment you stepped into the hallway, the call would drop. On mornings when I started the day early at home, I still remember telling people on work calls, “I’ll rejoin once I get outside and can connect to the cell tower.”  
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Fast forward to today, and while smartphones and networks in general have improved dramatically, that underlying issue hasn’t really gone away. In fact, indoor cellular coverage remains one of the more persistent challenges in modern buildings, especially in multifamily properties.
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The Move from POTS to Wireless and Fiber

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The shift from landlines to wireless connectivity has fundamentally changed how multifamily buildings are designed and operated. For most residents, smartphones are now the primary line of communication. Meanwhile, copper-based POTS lines are being phased out in many markets as carriers prioritize fiber expansion to keep up with massive connectivity demands.  

Fiber has become the preferred infrastructure for new deployments and is generally more resilient as a transmission medium. However, unlike copper, it does not provide inherent power. Traditional phone lines carried their own electricity, while fiber connections require powered equipment, changing how redundancy must be designed.
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This shift affects more than resident connectivity as elevators, fire panels, and other life-safety systems increasingly rely on cellular equivalents, often referred to as “POTS in a box,” to provide similar levels of resiliency.  
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Addressing Cellular Coverage Gaps

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The dependence on wireless infrastructure is only increasing. Industry analysis shows that roughly 80 percent of mobile calls and data sessions occur indoors, yet many buildings are still designed with the assumption that cellular service will simply work.

In multifamily properties, that assumption can create problems quickly. Residents expect their phones to function everywhere, including inside the unit, in common areas, and in the garage. When coverage drops between those spaces, complaints soon follow and the property’s reputation can suffer.
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So, what are the realistic options for addressing indoor cellular coverage in multifamily buildings? There are three primary approaches developers and owners typically consider.

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Option 1: Cellular DAS — Technically Excellent, Rarely Practical

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A Distributed Antenna System (DAS) is often considered the gold standard for indoor cellular coverage. When properly designed, it brings carrier signal into the building and distributes it through a network of antennas, delivering strong and consistent performance throughout.
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From a technical standpoint, it delivers high-quality 5G LTE cellular signal across carriers (Verizon, AT&T, T-Mobile).  
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However, DAS systems can be expensive, complex, and require coordination with multiple carriers to source signal. They make sense in airports, hospitals, stadiums, and large commercial towers where density and scale justify the investment. Even some ultra-luxury or high-rise multifamily properties might be a good candidate for DAS, but in most multifamily projects, it simply doesn’t make practical sense. The cost rarely aligns with underwriting expectations, and it generates no ancillary revenue to offset the investment.
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Option 2: Boosters — Targeted but Limited

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Boosters or BDAs (Bi-Directional Amplifiers) are more common in multifamily developments. A typical system captures outside cellular signal through a rooftop antenna and rebroadcasts it inside the building. When the outdoor signal is strong, this can improve indoor performance.
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Boosters can be particularly effective in targeted areas such as parking garages or public safety zones. However, they depend entirely on the strength and stability of the external tower signal. New construction nearby can block signal paths, and longer cable runs in larger buildings can introduce performance loss.
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They also rarely support all major carriers equally. A booster may improve signal for one or two providers while offering little benefit for others. While less expensive than DAS, the performance trade-offs often limit their effectiveness in larger multifamily properties.

Boosters solve specific problems. They do not create seamless, property-wide coverage.

One important consideration is the strength of the outdoor signal. If reliable coverage is not available on the roof, it’s likely there’s insufficient signal to rebroadcast effectively inside the building.  
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Option 3: WiFi Calling  — The Difference Managed WiFi Makes

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Most residents already use WiFi calling inside their unit. If they have a router in the apartment, the phone can route calls over WiFi instead of relying solely on the cellular signal.
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As mentioned earlier, that only works until they step into the hallway, ride the elevator, or head down to the garage. Even a short walk to the fitness center can be enough to drop a call tied to a home router.  
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Retail internet setups were never designed to create continuous coverage across an entire property. Each unit operates independently. Once a resident leaves their apartment, that coverage drops off.
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Properly designed managed WiFi changes the equation.
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In a managed WiFi model, the building deploys a centrally managed wireless network that serves individual units and shared spaces, rather than relying on ISP-provided routers in each apartment. Coverage extends across units, hallways, lobbies, and elevators.
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Access points can be placed strategically in garages and transition zones, reducing dropped calls as residents move throughout the property. Platforms such as CommScope RUCKUS also allow voice traffic prioritization, helping ensure WiFi calling remains stable even during periods of high network usage.
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This approach does more than improve phone calls. Importantly, it supports EV charging connectivity, smart building systems, and future services that depend on consistent wireless access.
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What Makes Sense for Multifamily Properties

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Each of these options has a place in multifamily buildings. DAS delivers excellent performance but is rarely cost-effective in residential developments. Boosters can improve coverage in targeted areas and may be appropriate in certain scenarios. WiFi calling inside individual units works but only within the limits of the router’s coverage.

For most multifamily properties, a properly designed managed WiFi network offers the most practical balance. It leverages infrastructure already being installed, scales across the property, and supports not just resident connectivity, but amenities like EV charging and life-safety systems.
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Years ago, losing a call meant climbing the stairs and reconnecting to a tower. Today, residents expect that transition to be seamless. Designing for that expectation is now part of building modern multifamily infrastructure.