There is no one-size-fits-all solution for the cellular coverage holes, dropped calls, unreliable connectivity, and poor reception that plague employees and guests inside middleprise buildings (i.e., those that are up to 500,000 sq. ft.).
Carriers and system integrators have all been challenged by the demands for better cellular reception in commercial buildings whether they are in dense metropolitan areas, factories in remote and rural locations, underground bunkers, or metal trailers on construction site offices.
Active and passive DAS solutions, as well as hybrids, provide varying degrees of uniform in-building cellular coverage at different price points. While the complexity and performance of these solutions cover a broad range, there are several common situations when the macro signal doesn’t penetrate into buildings that the solutions need to resolve:
- Congested macro network in metro areas resulting in insufficient capacity and/or poor signal-to-noise ratio
- Buildings taller than the 25-30 ft macro sites generally installed in metro areas
- Pilot pollution from too many visible cell sites with no strong dominant donor cell
- Extremely weak signal outside the building in rural, mountainous, or other areas with external obstacles
- No place to attach external donor antennas at optimum locations or building owner won’t allow them
- LEED or shielded buildings or rooms and energy efficient windows in combination with any of the other scenarios above
- Carrier reluctance to approve a rebroadcast agreement due to concerns with overloading the macro network
For several years, major carriers have offered enterprise small cells as the solution to these situations. While a small cell can deliver the additional signal capacity to a building, small cell deployment has not been as easy a fix as the plug-and-play initially promoted. Depending on the carrier and the deployment model, users may need to have a dedicated data feed for each small cell, which is a recurring expense, normally incurred by the owner (not the carrier). Interference between multiple small cells in a space, coverage gaps on the edges or between the coverage bubbles of each unit, technical complexity, slow delivery times, and high costs have all severely reduced the volume of small cell deployments that were initially projected.
The Cel-Fi QUATRA Supercell eliminates these issues. A Supercell is created when the Cel-Fi QUATRA active DAS hybrid is tethered to a small cell for the donor signal. A Supercell distributes uniform signal from the small cell throughout the building without coverage gaps or spotty coverage for one or multiple carriers simultaneously.
“There’s been three different scenarios where we’ve used a small cell and installed a Supercell. The first scenario is where the macro network outside of the building is really weak and won’t support an external rooftop antenna. You’re not going to be able to get enough of a donor signal from the rooftop to support a QUATRA off-air install,” says Dan Connolly, President of Atlantic Technology Group, an AT&T Solution Provider. “The second scenario is where the macro network is really congested so the performance doesn’t work well. The third scenario is where we have a customer that already has an existing small cell and wants to extend their coverage footprint.”
In a Supercell, the Cel-Fi QUATRA Network Unit, or headend of the system, is tethered to one or more small cells. Using Ethernet cables, the Network Unit is connected to the Coverage Units, which are intelligent active antennas that can be placed anywhere inside the building with RF and Power over Ethernet so there is no signal attenuation right to the building perimeter and no need to install additional power outlets.
“A Supercell greatly enhances the ability of a small cell to extend to a lot of different areas,” says Gary Greening, Vice President of Operations at Pacific Services, an AT&T and Verizon solutions partner. “You can broaden the footprint in a building or across multiple floors; we have even done multiple buildings off one small cell signal source.”
This has a major impact on the cost of the solution, Gary explains. “Every time you put in another small cell, each one costs $3,000 to $5,000. Each one has to have its own GPS antenna. Each one has to have a backhaul connection to the ethernet network. It’s not convenient. If it’s in different parts of the building, you may not have a way to get that GPS antenna on there, and you may not have the power where you want it. As Cel-Fi QUATRA uses POE (Power-over-Ethernet), it’s really easy. Just extend the cable out and hang a coverage antenna where you need coverage.”
Understanding the challenges the middleprise has faced with in-building cellular coverage, carriers have been working with their system integrator solution partners to offer their subscribers a choice of solutions.
“Many times we get a referral from the carrier telling us their solution is way too costly for the customer. They know we’ve already worked with many of their customers so are regularly passing us opportunities to see if we have a solution,” says Gary. “Cel-Fi QUATRA is one of our leading solutions for medium to small clients, under 500,000 square feet, and it’s been very successful. We have been able to install a QUATRA Supercell for 50 to 60 percent less than the cost of other proposals the clients received.”
For case studies of Supercell installations for private and public venues, download “Supercell Case Studies: Solving poor cellular coverage inside buildings when there is inadequate macro donor signal”.
About Paul Rigatti
Paul Rigatti is a Supercell Solutions Architect and Technical Sales Director at Nextivity, Inc. Previously, he spent 10 years as an engineer and consultant deploying cellular infrastructure end-to-end – from mobile devices to the RAN to the core –working with Qualcomm, Ericsson and Broadcom on the ground in 23 countries.