The Future of Connectivity Is Indoor

Why the Future of Cellular Is Moving Indoors

Cellular networks were originally planned around wide-area outdoor mobility. Buildings were treated as places that outdoor signal might reach, not as the primary place where mobile connectivity would be experienced.

That assumption is changing.

People now spend much of their connected day inside commercial buildings, campuses, healthcare facilities, hotels, mixed-use developments, multifamily properties, and large public venues. Mobile devices support communication, authentication, collaboration, access, security, operations, and daily tenant experience.

The Ericsson Mobility Report found that mobile data traffic grew 19% year-over-year between Q1 2024 and Q1 2025. That growth does not stop at the building entrance. It follows users into lobbies, offices, meeting rooms, garages, amenity spaces, elevators, and high-density shared environments.

5G adds another planning layer. Many 5G deployments use a mix of spectrum bands, including higher-frequency capacity bands that can be more sensitive to building penetration, distance, and indoor obstructions. Owners cannot assume that outdoor 5G coverage will automatically create reliable indoor 5G performance.

The next phase of cellular strategy will be less about hoping outdoor networks can penetrate buildings. It will be about designing buildings with indoor cellular performance in mind.

For owners, this makes connectivity a capital planning issue. Reliable indoor cellular is no longer just a tenant convenience. It is part of the building’s operating environment.

Why Smart Buildings Need Reliable Cellular Infrastructure

Smart buildings are increasing the demand for reliable indoor wireless connectivity.

That demand is not limited to phones. Commercial buildings increasingly rely on connected systems for access control, energy management, occupancy analytics, building automation, security workflows, visitor coordination, work order systems, environmental monitoring, and operational resilience.

Some systems use Wi-Fi. Some use wired networks. Others may use public cellular, private wireless, CBRS, or cellular as a backup path. In many buildings, the long-term answer will be a mix of technologies.

Cellular matters because it gives buildings another layer of connectivity that does not depend entirely on the local enterprise network.

The scale of connected-device growth reinforces the trend. Ericsson forecasts total cellular IoT connections will reach 4.5 billion by the end of 2025 and approach 8 billion by 2031. Memoori projects IoT devices in commercial buildings will grow from approximately 2 billion today to 4.12 billion by 2030.

That growth changes what owners need from indoor cellular infrastructure. The future building is not only serving tenant smartphones. It is supporting a wider ecosystem of people, devices, systems, and applications.

That requires a cellular strategy that can scale with the building.

Why Traditional Indoor Coverage Models Are Under Pressure

Traditional indoor cellular models are under pressure because the market has changed.

Outdoor networks remain essential, but they were not designed to be the primary connectivity layer inside every commercial building. As indoor demand grows, owners cannot assume that outdoor signal will provide consistent indoor service across every floor, core area, garage, elevator bank, and shared space.

Off-air approaches can be useful in the right environment, but they depend on outdoor signal quality and capacity. That outdoor signal can change based on network demand, time of day, surrounding conditions, and donor antenna placement.

Carrier-funded DAS signal source deployments are also more selective than they used to be. Carriers continue investing in network performance, but they often prioritize capital where it supports broader outdoor coverage, capacity growth, high-traffic venues, and priority network metrics. That can leave many commercial buildings without a carrier-funded signal source path that matches the owner’s timeline.

For owners, this creates a planning gap.

The building needs reliable indoor cellular. Tenants expect it. Smart-building systems increasingly depend on it. DAS can be the right distribution architecture. But the traditional path to a carrier-funded signal source does not always align with the building’s timeline or business case.

That is why owners are taking a more active role in indoor cellular strategy.

Why Signal Source Innovation Matters

The future of in-building cellular depends on solving the signal source problem.

A DAS distributes cellular signal through the building. It does not create that signal on its own. The signal source feeds the DAS, and the signal source model affects performance, capacity, deployment timing, carrier coordination, budget, and long-term support.

That distinction is central to future planning.

An owner can invest in the right DAS distribution layer, but the system still needs a reliable signal source that fits the property’s requirements. If signal source strategy is left unresolved, the project can become dependent on outdoor signal variability, carrier funding cycles, or timelines outside the owner’s control.

For a deeper technical breakdown, see why signal source is the most important decision in a DAS deployment.

Signal source innovation matters because buildings need more predictable ways to bring carrier signal indoors. Owners need a model that supports the building’s operating plan, not a process that depends entirely on whether a carrier chooses to fund the project.

This is where the market is moving. Indoor cellular is becoming building infrastructure. Signal source strategy is becoming part of that infrastructure decision.

The future of indoor cellular will belong to buildings that treat connectivity as infrastructure, not as a signal that might reach indoors from outside.

How Forté Supports Long-Term In-Building Strategy

Forté Neutral Source is an enterprise-funded, managed small-cell-based signal source for DAS.

It helps commercial real estate owners bring multi-carrier cellular signal into a DAS without depending on traditional carrier-funded deployment models.

For owners, the value is control. With CTS Forté Neutral Source, the building team can plan around the property’s requirements, timeline, budget, carrier needs, and long-term operating model. The project does not have to wait indefinitely for a traditional carrier-funded path to align.

Forté is designed for buildings that need a managed signal source path for DAS. It supports a more predictable approach to indoor cellular by combining signal source planning, carrier coordination, managed service delivery, and long-term support.

That matters for owners thinking beyond the next tenant complaint. A properly planned signal source strategy can support current mobile requirements while also giving the building a better path for future spectrum, carrier, and network requirements.

CTS helps property teams evaluate coverage conditions, compare signal source options, coordinate carrier requirements, and design in-building wireless strategies around the building’s actual needs.

For most owners, the direct path is through CTS and CTS Forté Neutral Source. Forté is also available through third-party integrators in select project contexts, but the owner’s strategic question remains the same: how will the building secure a reliable signal source model that supports the DAS over time?

How to Plan for the Next Decade of Indoor Cellular

The next decade of in-building cellular will reward owners who plan ahead.

That does not mean every building needs the same architecture. A smaller property with limited coverage issues may not require the same strategy as a large office tower, hospital, mixed-use development, campus, hotel, or high-density residential property.

But every building should evaluate cellular as part of its long-term infrastructure plan.

Key planning questions include:

• Where does indoor cellular performance fail today?
• Does the building need single-carrier or multi-carrier service?
• Which carriers need to be supported?
• What capacity will the building need during peak use?
• Which building systems may rely on cellular now or later?
• Is DAS the right distribution architecture?
• What signal source model fits the building’s timeline and budget?
• How will the system be monitored and supported over time?
• What future spectrum, carrier, or network requirements should be considered?

Owners should also think about how indoor cellular fits into broader property strategy. Connectivity affects leasing, tenant experience, operations, safety workflows, technology readiness, and future smart-building initiatives.

For CRE-specific planning context, see CTS’s guide to signal source strategy for commercial real estate.