What is a femtocell? A guide to improving coverage

Building structures, obstacles, and geography can impact the range, strength, and reliability of cellular coverage in buildings and offices. This interference can make it hard for employees to talk and connect using phones, laptops, or tablets.  As a solution to this problem, femtocells provide dependable and reliable indoor coverage in environments where physical barriers make it difficult to send and receive signals from a nearby cell tower.

A femtocell is a small, low-power cellular base station designed to enhance network coverage and improve signal quality in areas with weak cellular signals. Much like a hotspot, a femtocell transmits and receives cellular signals to and from mobile devices that are then transported via the service provider to broader network infrastructure.

Femtocells enable businesses to leverage an existing broadband connection and maintain security and privacy over their data. While we often speak about how connectivity solutions benefit those purchasing them, the benefits of femtocells extend to all who use them. The key is to provide better in-building cellular coverage. When that happens, it results in better user experiences for employees, customers, patients, and business partners.

Learning the ins and outs of femtocell technology and when and how to deploy it can go a long way in securing your network and improving end-to-end business communication.

[Read: Business internet connections: What are your options?]

To understand how femtocells work and improve cellular connectivity, it’s important to understand the difference between coverage and capacity.

Coverage is how far a signal can travel from a cellular base station to a mobile device. An adequate signal enables users to make and receive calls, send texts, and browse the internet. But the further you get from the base station the weaker that signal becomes, which is common in rural areas where towers are fewer in number. Cellular signals also grow weaker with each object they pass through. Some materials like concrete and tempered glass—even geographical features like hills and canyons—may stop signals completely.

Then there’s capacity. Capacity refers to how much data can travel over a network at one time. A network with many users sending and receiving data at the same time may experience a slower connection or none at all. If your device has ever shown full bars but you were unable to send a text, make a call, or load a web page, then it’s likely the network was at maximum capacity even though your phone said you had coverage.

Femtocells boost cellular strength and coverage in indoor areas where cellular connectivity is spotty or nonexistent, providing access where employees or customers might not otherwise have it. They’re also LTE/5G capable, offering greater capacity and lower latency than previous cellular technology. 

Femtocells elevate the user and overall business experience. But like any technology, there are limits. In most cases, being mindful of these limits is all that’s necessary. In other instances, it may be as simple as choosing the right femtocell manufacturer or speaking with your service provider to uncover a solution strategy best suited for your business or building.

Limited range of femtocells

In areas where existing coverage is weak or nonexistent, a mobile business user risks dropping calls or losing their cellular connection if they move outside femtocell range. However, if cell tower coverage is sufficient the call will be handed off to the nearest tower once the user moves beyond femtocell coverage so it can continue without interruption.

Carrier and mobile device specific

Business Wi-Fi connections are ideal when you want to provide connectivity to a broader set of users. However, unlike business Wi-Fi—where any mobile device can connect as long it has access—femtocells are not carrier agnostic. Some are tied to a single carrier, while others allow more than one but not all. There are also limits on how many active mobile users it will support at any one time. Femtocells used in residential homes support anywhere from four to eight users while enterprise business models can support a dozen or more, though the technology is always improving.

Shared bandwidth issues

Because femtocells connect via DSL or broadband, they risk having to share bandwidth with other devices on the network like desktop computers, IT equipment, or IoT devices. In these shared-bandwidth scenarios, mobile device users may experience reduced network performance and productivity issues. In this scenario, a business may choose to have two separate networks.

Femtocell pros and cons

Pros

• Broadband agnostic
• Secure, reliable coverage
• Greater voice quality
• Increased battery life for mobile devices
• IoT and 5G/LTE capable

Cons

• Limited range
• Potential interference with cell towers
• Limited number of carriers and users
• Shared bandwidth with other network devices
• Compatibility issues when using different providers

Much like femtocells, small cells use low-powered radio access nodes, or antenna, to transmit and receive cellular radio signals which are then transported over a core network via fiber optic cable. They are larger in size and power than femtocells, which is why they’re capable of a larger range. At roughly about the size of a pizza box, their range can be from a few hundred yards to a little over a mile in rural areas.

As of 2022, there were over 450,000 small cells in operation in the U.S. with that number steadily increasing.¹ This is in large part due to 5G technology and its ability to deliver greater network capacity and lower latency. While cell towers—also referred to as macrocells—are 5G capable with ranges that extend for miles, small cells offer a quicker and less costly option on account of their size and ease of installation.

You’ll also find them affixed to building exteriors, light poles, and other structures in areas where a cell tower is not an option—like densely populated urban areas. Given a telecommunications provider could install as many as 20 small cells for the cost of one cell tower, it’s understandable why small cells are so popular.

The increased use of mobile devices, applications, and data and video sharing platforms in business has fueled the need for increased connectivity, greater bandwidth, and faster speeds. 5G technology makes this possible, delivering higher data transfer rates, lower latency, and superior network capacity using high frequency millimeter waves.

Although high frequency waves enable mobile users to do more in less time, they do not travel as far as previous cellular technology. While cell towers do deliver 5G connectivity, distance and obstacles remain a factor in how much coverage they provide. This is particularly challenging for commercial buildings and office complexes with interior walls or construction that uses high-density or specialized materials.

Femtocells and small cells bridge this cellular connectivity gap, enabling the use of 5G by providing coverage in places where distance or physical limitations make it difficult to maintain a consistent and reliable indoor cellular connection.

Businesses are quickly embracing the use of femtocells for the reasons we’ve discussed with the benefits extending to companies of all sizes, types, and industries. Naturally, this should come as no surprise considering how much we rely on mobile devices in our day-to-day. While reliable, uninterrupted coverage helps attract and retain customers, patients, and business partners, it also enables us to do more with the time we have. This is especially important in time-sensitive occupations or when speedy and accurate service is key to business success.

Restaurants

Many restaurants provide free Wi-Fi to customers to improve the customer experience. But heavy video streaming and file sharing lead to slower connections. This combined with dead spots or weak coverage impacts the overall customer experience. It also affects productivity and service if the mobile devices employees use to enter orders and process payments are operating on the same Wi-Fi network.

A femtocell restricted for use with employee devices ensures customer data such as credit card information remains secure, preventing unauthorized access and data breaches. It also gives employees the coverage and capacity they require to perform their duties without having to share bandwidth with customer devices.

Medical practices

Multiple examination rooms with thick interior walls and heavy equipment affect how far a cellular signal will travel. With a growing number of medical staff using mobile devices like tablets in their day-to-day, femtocells provide the necessary security, coverage, and bandwidth with signal strength strong enough to penetrate such obstacles and improve the doctor-patient relationship. This is especially important when it comes to protecting health data and other private information related to insurance or payments.

Business offices

Interior walls. Business equipment and furniture. Multiple devices competing for the same cellular connection. Even staff. Each of these factors affect cellular coverage. Installing femtocells helps provide reliable in-building coverage so employees continue to conduct business at a high level with their mobile devices.

Generally, when people think of ways to boost the cellular signal in their home or office a signal booster is the first thing that comes to mind. However, unlike a femtocell, a signal booster requires an existing cellular signal to amplify or boost it. If there is no existing coverage, or the signal is too weak, a signal booster will be ineffective. There is also risk that company or customer information could be exposed when using a public cell tower.

Because it is connected to an existing DSL or broadband network, a femtocell broadcasts its own signals rather than relying on a cell tower. This gives businesses a more dependable and reliable cellular coverage option plus greater security and privacy protections because it is a private network.

As you’ve probably guessed, many factors go into determining which cellular coverage solution is right for you. We recommend connecting with an AT&T Business expert so that we assess your needs and devise a solution best suited to your circumstances. Our femtocell, cell booster for business solution is AT&T Cell Booster Pro, which is capable of bringing fast, secure, and reliable in-building coverage to buildings up to 100,000 square feet.

For buildings 100,000 square feet or above, our AT&T On-Premises Cellular Network offers flexible LTE/5G cellular connectivity options using Distributed Antenna Systems (DAS) and small cells. It also supports Multi-Access Edge Computing (MEC) solutions.

No matter which path you choose, our solutions can be bundled with other AT&T Business services to give you the secure, reliable, and dependable network coverage your business deserves.

See how ultra-fast, reliable fiber and 5G connectivity protected by built-in security give you a new level of confidence in the possibilities of your network. Let our experts work with you to solve your challenges and accelerate outcomes. Your business deserves the AT&T Business difference—a new standard for networking.

To learn more about AT&T Cell Booster Pro, view our product brief and visit our AT&T Cell Booster Pro webpage. Or to speak with an expert who knows business, contact your AT&T Business representative.

¹“Wireless Infrastructure By the Numbers: 2022 Key Statistics,” Wireless Infrastructure Association, March 15, 2023, https://wia.org/wireless-infrastructure-by-the-numbers-2022-key-statistics/.