The Implementation of Distributed Antenna Systems

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.”

DAS AND EDUCATION