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In-Building Wireless Enhancement Systems, DAS & BDA Solutions

Why do you need an In-Building Wireless Enhanced System?

SEI Wireless Solutions design and implement In-Building Radio Enhancement Systems that amplify two-way radio and cellular signal for Public Safety. SEI Wireless Solutions understands two-way- radio and cellular technology, the needs of those who use it, and the complexities of regulations governing first-responder communications. With over 30 years of industry know how and skilled experience, SEI is your ideal partner to design, implement and manage your in-building communication systems with the proper coverage for first responders, public safety, and cellular reliability.

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In-Building Wireless Enhanced System

A Radio Enhancement System is made up of three parts:  
BDAs (Bi-Directional Amplifier), DAS (Distributed Antenna System) and Donor Antenna Systems.

A BDA (Bi-Directional Amplifier) system is an in-building communication system that brings wireless signals into a structure from outside, amplifies those signals with a signal booster, and then evenly distributes the amplified signals throughout a structure via a Distributed Antenna System (DAS). Each DAS / BDA solution is custom-designed for each unique environment. Variables such as building materials, dead spots, and signal interference offer specific challenges. SEI has extensive experience deploying in-building wireless systems and can address your building RF needs.

A BDA is a part of a Distributed Antenna System (DAS), which is a network of separate antenna nodes connected to a common transport medium.  BDA and DAS equipment are referred to as Wireless In-Building Solutions. However, DAS may not be part of a BDA solution. These two-way radio signal boosters are used to bring facilities into compliance with Emergency Responder Radio Coverage (ERRC) code. ERRC code is the standards which apply to Public Safety DAS and radio enhancement systems as mandated under International Fire Code IFC-510
and the National Fire Protection Association standards NFPA 72, Chapter 24. These regulations are complex. SEI can help make it easier for you.

Today state governments and city municipalities are now enforcing these public safety codes. SEI will help you be sure your building is compliant.

Bi-Directional Amplifiers, Distributed Antenna Systems & Donor Antenna Systems

Bi-Directional Amplifiers (BDA)
Bi-Directional Amplifiers (BDA) are signal boosters that sustain two-way radio communications throughout a facility, which includes stairwells, underground tunnels, parking garages, and other challenging areas. BDAs are amplifiers/repeaters available in a variety of gain and power options, they boost and distribute a radio or cellular signal covering various frequencies.

The Bi-Directional Amplifier receives a signal from the donor antenna and amplifies the signal inside the building.  It also receives transmitting signals from handheld devices inside the building and sends them out to the communications tower through the donor antenna.  BDA's work best when connected to a network of in-building antennas called a Distributed Antenna System (DAS).

Distributed Antenna System (DAS)
A Distributed Antenna System (DAS) is comprised of coaxial cable, unequal power dividers & splitters and ceiling mounted antennas.  In large facilities, fiber is used instead of the coaxial cable. The DAS creates a path for the radio signal to go from the BDA to the network of spatially separated antenna nodes. When designing a DAS Solution, the DAS antenna elevations are generally at or below the clutter level, and node installations are compact, so they do not take up much real estate. A distributed antenna system may be deployed indoors (an iDAS) or outdoors (an oDAS). When selecting a vendor, be sure to focus on good design, because it is essential to when implementing a smart DAS Solutions that will provide a reliable signal to an entire facility.

Donor Antenna System
Every DAS System consists of basic components, the first is the donor antenna, which is usually located outdoors and above the tree line to directly recurve RF signals from a cell tower or signal source. The donor antenna can receive multiple frequencies to meet emergency and large capacity needs. Once the signals are received by the donor antenna, they are transported to the head-end equipment room via coax cabling.

Think of the donor antenna is the eyes and ears of the DAS solution, and the head-end equipment room is the brain of the system. This is where the repeater, or bi-directional amplifier, collect the RF signals for redistribution. The bi-directional amplifier is a very important component in a DAS solution. Without it, the RF signals would continue to grow weaker as they traveled a farther distance from the donor antenna.

The donor antenna is installed on the building’s rooftop.  It is pointed at the nearest communications tower and responsible for bringing the signal into and out of the building.  Since it is the most important antenna in a Radio Enhancement System, SEI Wireless uses category 5 hurricane-Rated bracketing and R-56 Lightning Protection standards.

two-way radio solutions

DAS and BDA Design Types

  • Primarily Co-Ax infrastructure

  • Uses powerful bi-directional amplifier at the headend

  • Lower equipment cost but higher installation cost

  • All carrier frequencies on the same system

  • Uses antennas & leaky coax

  • High RF losses

  • Best suited to small facilities and lower frequencies (800MHz)

  • Minimal management capability

  • Network devices using Ethernet infrastructure

  • Smaller distributed amplifiers

  • Uses active interface devices to carriers

  • Proprietary & non-proprietary implementations

  • Highly scalable

  • Capacity expansion using LTE MIMO

Industries & Applications

Almost all industries need reliable and highly accessible data and voice coverage to mobile devices. SEI has extensive experience in these industries from our Two-way-radio business to our DAS | BDA Solutions:

Convention Center
The need to provide everything from live-streaming videos, social media-enhanced presentations, faultless wireless internet and enough charging stations for computers and phones. Today’s convention goer expects connectivity everywhere.

Hospitals | Healthcare
In the health care industry, specifically in the hospital environment, doctors and healthcare professionals are relying more on tablet communications even in operating rooms, labs, elevators and stairwells.  This growing demand is being challenged by today’s building design that utilizes Low-E glass and new building materials that degrade cellular signals. A ‘distributed antenna system’ (DAS) is designed to amplify cellular signals throughout the building.

Universities | Education
Education demands information. Educators, administrators, and students use smartphones, tablets, and other cellular-connected devices for learning, collaborating, directing, and socializing. School campuses today need a strong, reliable cellular signal to enable education and administration. Students expect coverage. Everyone expects first responders to react with the utmost urgency when it comes to our children. Students and faculty use multi-carrier and complex digital learning today. Parents want instance access to kids, not to mention landlines are scarce today.

Travelers are now making decisions on lodging based on many factors, good connectivity is expected. Poor service could negatively affect the reputation of the establishment.

Public safety is key for any public venue like a sports center. People gather in large numbers; it is essential that first responders can communicate in case of an emergency. There are many other new applications too that a BDA | DAS helps, such as (please share these new cool applications) At the Dolphins Stadium SEI knows first-hand these essential elements of what makes a DAS application fine-tuned to meet the needs of the property management as well as the fans.

Engage SEI Wireless

SEI Wireless Solutions offers end-to-end BDA and DAS solutions. We provide you:

• A BDA | DAS Needs Assessment – SEI will gather the requirements, send and skilled engineer onsite to do a site survey. We know how to find your building coverage challenges
• A BDA | DAS System Design – we develop the right solution for you
• Carrier Engagement – SEI contracts with the right team to engage the carriers
• Code Compliance – Our broad knowledge and years of experience provides you peace-of-mind
• System Installation– we deliver whatever you need
• Maintenance and Support – SEI is tried and true. We stand behind our products and services.

Frequently Asked Questions

 Q: How long does it take to install a DAS application?

 A: That depends on numerous factors. If the building is ready, it can be accomplished in as little as 2-4 months. It also depends based on the size of the building.

Q: Can we finance the system?

 A: Yes, SEI provides financing. Inquire about financing for your project.

Q: How long does a needs analysis take?

A:  Site survey parameters will depend on how many frequencies are being tested and how large the property is.

Q:  How long does the design take?

A: It depends on the size of the project.

Q:  How much does a DAS | BDA Cost?

A:  A DAS | BDA Solution can range from as low as $25,000 up to $500,000+

Q: What is the difference between a BDA and a DAS?

A:  BDA means ‘Bi-Directional Amplifier’. It is a term primarily used for a Public Safety system, but can also be part of a DAS. DAS stands for ‘Distributed Antenna System’ and can encompass a BDA or repeaters and indoor antennas / outside donor antennas and cabling for each frequency needed.

Q: What carriers should we use?

A:  Whichever are either required for Public Safety or that you prefer (cellular).

Q:  What happens when we need a quote in the pre-construction phase?

 A:  During the pre-construction phase, SEI provides quotes based on floor plans. Pre-construction quotes are strictly budgetary. To come up with quotes, we take the building plans and use iBwave software for our estimates. We also factor in what we know about what the authority having jurisdiction (AHJ) will require. 

Resources & Partners

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Use Case – why BDAs | DAS systems are critical to Public Safety

Using mobile devices has become the industry norm for everyday use. This has made having reliable in-building coverage critical for public safety, in addition to everyday communication needs. Expectations are high for everything we do today; this includes quality safety, security, and speed. We expect all of our technology to work seamlessly, especially our devices. These high expectations come with a price tag. 

Have you ever walked into a building and had no coverage on your mobile phone? To make matters worse, when the coverage is spotty, chances are your phone was busy searching for connectivity, which drains the device battery.  We have all experienced this, but what’s worse, think of how deadly this could be if this occurred during a fire, a natural disaster or a tragic public event?   

On 9/11 our first responders were not able to effectively communicate inside the World Trade Center Towers. This catastrophic event was the catalyst that caused the industry to create new heightened standards in security and public safety. Back in 2009, the International Code Council and the National Fire Protection Association added first responder radio coverage requirements to their required fire codes for buildings.

Lack of signal coverage happens when the radio frequencies (both radio and cellular) are reduced when passing through dense building materials such as concrete and metal. Today we are building better buildings. New advances in disaster-proofing, storm resistance, and environmental sustainability are the essential parts of our landscape today.  New structures are built with enhanced building materials such as solid-poured concrete walls, and LEED-certified windows, which are critical for withstanding hurricanes. They do, however, inhibit clear coverage for radio signals and cell phone reception. These enhanced building materials keep radio signals from entering the building, which causes communication issues with mobile devices.


  • City of Sunrise Public Safety Complex – All frequency Bands, Police and Fire Rescue Administration
  • The “W” Fort Lauderdale, Hospitality – Public Safety BDA, Meisner Electric
  • One Plantation, Luxury Apartments Public Safety BDA & Cellular DAS, STILES Construction
  • Elan 1640, MDUs, –Cellular DAS, STILES Construction
  • Motorola, Enterprise CorporationPublic Safety BDA, Fisk Electric
  • 8th Avenue Residences, MDUs, Public Safety BDA, STILES Construction
  • Nine at Mary Brickell Village, MDUs, Public Safety BDA, The Lynd Company
  • Pinnacle at Tarpon River, MDUs, Public Safety BDA, Pinnacle Housing
  • Brickell View Terraces, MDUs, Public Safety BDA, Pinnacle Housing
  • Crimson Tower, MDUs, Public Safety BDA, Facchina Construction 
  • The Fresh Market, Public Venue – Commerical, Public Safety BDA, J Raymond Construction
  • LA Fitness,  Public Venue – Commerical, Public Safety BDA, J Raymond Construction
  • Franklin Academy, Education, Public Safety BDA, McGarvey Development
  • Sheraton Suites, Hospitality – Commerical, Public Safety BDA, Fillmore Hospitality
  • Palmetto Park Promenade, Public Venue – Commerical, Public Safety BDA, KAST Construction

Glossary of BDA | DAS

      AHJ – Authority Having Jurisdiction

      Aggregater – A 3rd party company that designs, builds, finances, operates and maintains the DAS system. They will also negotiate agreements with the carriers on the landlords’ behalf.

      Lead Carrier – A cellular carrier that also fills the role of an aggregator.

     Carrier – ATT, Verizon, Sprint. They pay for it. Cost shared, depends on how large.  Typically a single carrier, Carriers may form a consortium.

     Neutral – host – a 3rd party that will negotiate with the Carrier and the Landlord, to get ubications  Enterprise or Public

    Landlord – funded by building owner, deployed and operated by DAS integrator, Carriers 3rd party may partially fund. Multi Carrier

    Public Venues – large events, interest from many carriers, lease arrangments


   Radio Enhancement System is made up of three parts:  Donor antenna system, BDA, and DAS.

   Emergency Responder Radio Coverage (ERRC) code

In Summary, why SEI for your BDA | DAS System

SEI Wireless Solutions knows two-way-radios, and the need for reliable communications does not stop at the door of a building. Increasingly, public safety entities, commercial wireless service providers, and wireless users require reliable communications inside buildings. For public safety, reliable coverage is often essential throughout a broad jurisdiction, including coverage on-street, and in buildings. In such cases, there is no substitute for a properly designed dedicated mission-critical communications system with sufficient transmit sites to provide the level of signal required for reliable coverage anywhere within the jurisdiction, whether outside or indoors.

RF in-building coverage has become a fast-growing market in recent years. Commercial wireless users increasingly demand reliable communications inside office and residential buildings for their business and personal needs. At the same time, local municipalities have issued ordinances to ensure that construction of new buildings includes adequate radio coverage of public safety signals. Efforts are also underway to develop and implement national level model codes for public safety in-building communications, as seen by recent initiatives at National Fire Protection Association (NFPA) and the International Code Council (ICC).

SEI is a leader in the installation of in-building RF coverage. Call today to speak to one of our highly qualified BDA | DAS experts. Our passion for excellent customer experience will give you peace of mind when designing and installing your DAS| BDA Public Safety Solution. 


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