Chapter Corner

The Implementation of Distributed Antenna Systems

Posted in: Features, July 2015

Today’s wireless users expect to communicate anywhere and everywhere – from parking garages to elevators to crowded stadiums. And because more than 90 percent of American adults own a cell phone according to the Pew Research Center – more than half of which are smart phones – wireless connectivity is not something that can be ignored. As people become more and more dependent on their phones, the need for wireless coverage has moved indoors, and capacity is key.

That’s where Distributed Antenna Systems (DAS) come into play. DAS technology was designed to expand wireless coverage within and between structures, allowing cell phones and radios to function regardless of position within the building. DAS distributes cellular coverage through a system of cables and antennas, breaking through structural obstacles and heavy-duty building materials such as steel, concrete, and low-E glass.

A wide range of wireless services are supported by DAS, including cellular phones, public safety radios and wireless medical telemetry systems. And while DAS can protect the casual cell phone user from a dropped call or missed text, its function can also have important consequences, depending on the application.

“Hospitals have long been notorious for dropped calls and dead zones,” said Eric Toenjes, Graybar Business Development Manager. “Due to the age of the buildings, the building material, and the sophisticated, fragile equipment contained within the buildings, wireless connectivity can be a challenge. Furthermore, some newer, eco-friendly building materials can also interfere with wireless and data signals.”

Let’s say you are a contractor building a new hospital. A well-functioning DAS is crucial to the success of the building’s operations – the hospital and its personnel will need top-notch coverage for quick communication and access to patient information to deliver patient care. Furthermore, a good Distributed Antenna System can even allow for operational efficiencies through improved communication. From a customer-service standpoint, the hospital’s patients and visitors expect to have wireless connectivity at any location within the building.

Public safety personnel and first responders need reliable radio and cell phone coverage at all times and in all locations to keep the public safe. In an emergency, DAS is crucial and could be the difference between lives saved and lives lost. Cellular service for communication with building occupants is also critical. During a catastrophe, a phone call or mass notification via text message could save lives – whether in a hospital or virtually any other building setting. The FCC cites that cellular calls now represent 70 percent of all 9-1-1calls and 67 percent of 9-1-1 calls are made from a cell phone inside a building. In emergency situations where timing means everything, access to a strong cellular signal can save time and lives.

The events of 9/11 resulted in more rigorous local ordinances and building codes for heightened public safety. Current International Fire Code (IFC) and International Building Code (IBC) require benchmarking to prove sufficient signal or an operational in-building DAS system. Two codes/standards that require enhanced first responder communications are International Fire Code Section 510.1 Appendix J and the National Fire Protection Association 72-2010 Chapter 24. These codes outline requirements for DAS related to coverage, survivability of the system, signal quality, license and power back-up. During the building design phase, architects, builders and developers must adhere to codes and standards to obtain construction plan approval prior to final inspection.

“Too many people think DAS is a matter of convenience,” said Toenjes. “But in many instances, it’s a very critical matter of safety, which has been reflected in building codes.”


College campuses are also often in need of upgraded DAS. Students and staff at colleges and universities across the nation expect wireless coverage, and they need a network to back them up. Students want the latest technology, and may even require it. A survey by the Wi-Fi Alliance has found access to wireless technology could influence which school students choose to attend.

From a teacher’s laptop to a student’s smartphone or iPad, there are often more wireless devices on a college campus than there are people, with an average of four to five devices per student. In an academic context, wireless can be fundamental to the learning process. Due to the vast and increasing appetite for data, reliable service is now about network capacity versus coverage and carriers are focused on offloading capacity from overtasked outdoor cell sites. They want to take indoor users and segment them off from the rest of the network. Capacity enhancement is the primary investment that carriers are making on campus – but universities can’t control which cell carrier a student brings to campus, and students expect wireless from all carriers to work. A DAS system meant to handle any wireless provider is an obvious solution for these situations.

Furthermore, school administrators worry about security threats that students and staff have faced in far too many schools. In response to the need for effective emergency communications, many schools have implemented mass notification systems to alert students and staff of impending threats. During an emergency, communication via text message could save lives. Delivery of these text alerts relies on cellular coverage. Also, first responders need reliable radio and cell phone coverage indoors to facilitate their response, which can keep students and staff safe.


Implementing DAS can be a daunting task and involves many decisions: Who should I buy from? Which manufacturer is best? How much will it cost? How does it work? How long will it take? How will I get the cell carriers to participate in my system?

The roadmap to implementing DAS includes gathering requirements, determining financing and carrier participation, survey and design, proposal and pricing, infrastructure build, Carrier connection coordination, DAS commissioning, project documentation and system test and verification.

“If you’re working with a full-service distributor to help manage a DAS project, it’s imperative to determine the customers’ goals and needs before embarking on the project,” continued Toenjes.

It’s also critically important to make sure the carriers are involved throughout the process. Distributed antenna systems rebroadcast FCC licensed and regulated spectrum, Carrier approval and legal agreements are required with these types of projects. In fact, if carriers are not brought in at the coordination stage, your DAS system can be shut down, rendering your system unusable and open you up to large FCC fines.

Todd Reed is National Market Manager for Graybar, an IEC National Platinum Industry Partner. With five years of experience within a family-owned distribution business and 10 years as a Graybar employee, he knows the importance of efficiency, safety, and productivity for electrical contractors. As National Market Manager at Graybar, Reed’s goal is to find the best products and solutions to help contractors work more efficiently, stay safe on the job, and win more productive and profitable business.