Wireless connectivity has never been as crucial as today, with more people using smart devices in new and unique ways. Moreover, in a digital-run world shaped by social distancing, wireless capabilities have transcended convenience and become the primary means for human interaction.

Reliable and high-performing wireless coverage is then mandatory inside the comfort of homes and residential buildings. In-building wireless (IBW) solutions significantly help improve the coverage inside these facilities. The term 'in-building wireless' refers to communication solutions that maintain connectivity indoors. Often, network providers who seek enhanced delivery of services to their clients use IBW – particularly in demanding environments.

Figures show that 80% of call and data sessions are initiated indoors. Alongside the growing demand for smartphones and increasing data usage by consumers, the in-building wireless market is set to grow exponentially around $18 billion by 2025.

By nature, buildings are physical barriers to wireless communication. IBW solutions serve to address concerns involving dead zones that cause dropped calls, poor signals, and slow downloads. In addition, the question of capacity arises based on how many individuals are inside a building and the ability of cell towers to accommodate all connected devices within the area.

In line with quality of service (QoS) agreements and quality of experience (QoE) expectations, IBW solutions ensure that networks are capable to deliver. Keep in mind that there is no one-size-fits-all IBW solution as the correct installation approach is majorly dependent on the size of the building and the scope of wireless services required.

Types of in-building wireless systems

Getting excellent cellular service inside a building is among the most important aspects that commercial real estate owners and builders must ensure to all tenants, employees, and any individual within the premises.

With that in mind, mobile network operators (MNOs) and equipment vendors are prepared to offer their expertise in realizing the cellular connectivity needs of a building. Let us now categorize IBW systems from least to the most complex in terms of installation.

Signal boosters

Utilizing bi-directional amplifiers (BDAs) or repeater systems, signal boosters capture, amplify and repeat outside wireless signals inside buildings. How does this work? The outside signal is repeated via an antenna, which helps sustain communications throughout the facility.

Signal boosters can boost all frequencies broadcasted by one or more carriers simultaneously, making them great at improving coverage in specific locations, including SoHo units, small commercial buildings, parking garages, and other limited-spaced structures with poor or nonexistent coverage.

Known to be low in cost, signal boosters are not part of any mobile operator’s network nor do they require a wired broadband link to function. The signal booster works with an outside antenna that receives the signal from the local cell tower; an amplifier that simply takes the existing signal and boosts it up for use inside the building; and an inside antenna, usually mounted on a ceiling, that retransmits the boosted signal accordingly.

Hence, this IBW solution is ideal for small facilities in suburban and rural areas as it boosts signal strength without having to utilize a landline connection and reduces the impact of the building exterior getting in the way of signal transmission.

Small cells

To solve network capacity issues in narrow areas, small cell systems are built. They create a cell signal indoors that works suitably when there is no outdoor cell signal close by. Relatively easy and straightforward to deploy, a new small cell system can be designed, procured, installed, and commissioned as fast as 3 months.

These systems act as mini cell phone towers within a small-scale facility. They radiate a signal from inside the building to increase the strength of the signal received by devices. Unlike signal boosters, small cells need to be connected to a broadband landline internet service to work.

To illustrate, femtocells and picocells are two types of in-building small cells. Both femtocells and picocells are great at improving coverage in specific locations, mobile operators, and spectrum bands. They generate their own cellular signal but require an online connection to transport the voice/data back to the carrier’s network.

One femtocell typically supports between four to eight concurrent users/devices and is connected to the operator’s core network via a separate broadband connection (via cable, fiber, or DSL). They are self-configuring and operate at a lower power level (in the range of 20 milliwatts).

On the contrary, picocells typically have a higher power output (between 100 to 150 milliwatts) and, consequently, have a longer range and the ability to support a larger area, traffic capacity, and more concurrent users.

The upside to both types of small cells is their low cost relative to other solutions. Most importantly, there is no need to distribute the signal via cabling inside the building (aside from plugging the femto-/picocell into the wired broadband modem). Despite that, it still covers a short-range and can support a single MNO only. Thus, it will not work as efficiently for big spaces like airports, stadiums, hospitals, and convention centers.

Distributed antenna system

The simple principle behind a DAS involves placing antennas strategically throughout a building so that cellular signals can be distributed where needed. The signals may come from outdoors, in which case an external antenna receives and sends the signals to internal antennas, or the signals can come from an on-site carrier-provided base transceiver station (BTS). As a result, a DAS can increase cellular capacity for a building and allow wireless signals to reach end-user devices.

All DAS systems require two things: a signal source and a distribution system. A base station, small cell, or repeater at the head-end serves as the signal source, and fiber distributes the signal to the remote equipment. In other words, while small cells and signal boosters may consist of one or several individual units per facility, a DAS uses many interconnected devices spread over large facilities to increase connectivity and boost performance.

This is the reason why it is best for large facilities with the size of 100,000 sqft. to over 500,000 sqft. It provides greater reliability and if properly planned and designed, addresses the increase in bandwidth demand and brings connectivity in a single area from multiple telecom carriers.

To explain further, there are four kinds of DAS: passive, active, hybrid, and digital. Passive DAS uses radio frequency (RF) components like coaxial cables, splitters, taps, while an active DAS has a fiber-optic cabling backbone that overcomes the transmission losses that occur with a coax-based system.

Hybrid, as the name implies, is a mix between active and passive DAS. For this reason, remote radio units (RRUs) are separated from the antennas, enabling the use of both fiber optic and coaxial cables. Digital DAS is relatively new under the Common Public Radio Interface (CPRI) specification and utilizes a Base Band Unit (BBU) to connect directly to a master unit without analog-to-digital conversions.

In theory, digital DAS should be simpler and cheaper to deploy. But as an emerging technology, digital DAS has competing standards and has enjoyed little deployment so far.

Challenges, factors, and benefits

Issues regarding interference, designing, and installation are expected to pose challenges to the growth of the IBW market. In a world where business functions and consumer needs have been shifted to mobile, strong wireless coverage is more critical than ever.

Effective internal communications is vital whether a venue is fast-paced or simply capacious. A reliable internal communications strategy helps staff, tenants, visitors, management, and other individuals to collaborate and connect with one another. This will streamline business operations and build loyalty and satisfaction among people.

In-building wireless solutions manage the instability faced by the cellular carrier networks from the surge of data traffic (e.g. offices, hospitals, hotels, and shopping malls). In this case, DAS and small cells could cover reduced RF performance, power losses, and intermodulation distortion. The lack of stable indoor wireless network coverage and capacity issues has also driven the mobile virtual network operators (MVNOs) and neutral host providers to leverage IBW solutions.

By and large, the fastest-growing IBW solution is wireless (cellular). Nevertheless, this can also be complementary to Wi-Fi. As we enter a new world of connected devices such as autonomous cars and smart buildings, services provided by network carriers such as Verizon, AT&T, and T-Mobile must consistently deliver stronger signals for better service, reliable connections, faster data, and always-on dependability.

Regular Wi-Fi and small cell technology won’t be enough to prioritize reliability and signal consistency. Thus, in-building wireless systems are integrated. Most are designed to support multi-operators and multi-bands but no labyrinth of cables connecting antennas in various corners of the building exists. This makes DAS systems cheaper to obtain and install, compared to installing several small cells. Moreover, IBW installations can only be done by professionals. As a matter of fact, the Federal Communications Commission (FCC), which regulates DAS solutions, requires that in-building wireless systems are installed by licensed system integrators (SIs). This gives 100% assurance that the equipment manufacture has certified and commissioned the installer for system installation; removing concerns of possible network compromise.

IBW technology trends

There has been a rapid growth observed in the telecommunications market as 5G, IoT, and computing, among others, take shape in forming new wireless technologies. It opens more opportunities for building owners and enterprises in implementing wireless solutions.


Wireless communication is the major transformation that will come as a result of successful 5G deployment. 5G is still evolving and it comes with recent parallel developments, such as Wi-Fi 6, optical local area networks (LANs), smart buildings, and edge computing. In a 5G world of neutrality and localized spectrum, various companies might delve into becoming indoor system providers in able to get direct revenues from end-users or perhaps cut wholesale deals with operators.

It is worthy to note that small cells are a critical part of the foundation for building a 5G future and an element of network densification. Why so? Because it entails adding more base station connections to strengthen the existing wireless infrastructure. This is unavoidable as the demand for bandwidth escalates and network operators opt for reliable systems that can seamlessly bring 5G indoors.


Property technology solutions and applications require an underlying network to be successful – this is the IBW system. So while an IBW network can provide cellular service for the building occupants, it can also be used by the landlords and owners to support the building operations. In this way, proptech and IBW are both synonymous with each other and dependent on one another. Smart building-related applications/solutions such as security, video feeds, parking, location-based services, HVAC and/or lighting automation, etc. can leverage a robust IBW system. Other IoT-based applications that leverage sensors also make use of in-building wireless connectivity and compute power.

In the IBW realm, the impacts of building automation and IoT in general have a potentially greater impact on in-building networking requirements going forward. As cities and regions continue to densify, the burden on existing cellular networks intensifies. Consequently, it becomes more challenging to find reliable wireless signals inside buildings. Taking this into consideration, comprehensive wireless coverage that is future-proof, 5G-ready, and applicable to future PropTech needs is necessary.

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