Written by Bill Roberts, President, Network Services, Datatrend Technologies, Inc.
The most familiar component of a cellular network is the cell tower and the antenna installations on structures such as municipal water towers and skyscrapers. These large cell sites are called “macro” cell sites and enable wireless service providers to deliver voice, text, and broadband communications to today’s 400 million U.S. wireless subscribers.
Distributed Antenna Systems (DAS) are installed when existing outdoor wireless networks do not provide adequate coverage inside. In areas with insufficient coverage, a DAS effectively provides wireless coverage for mobile telephones, two-way radios, and wireless LAN devices in buildings, tunnels, underground parking garages, or anywhere outdoor radio signals do not reach.
DAS networks are attractive solutions because they are scalable and flexible. DAS networks include:
- Remote communication nodes (at least one antenna for transmitting and receiving the wireless service provider’s RF signals)
- Signal transport medium (typically fiber optic and Category 6 cable)
- Radio Transceivers or other head-end equipment
A DAS network can be designed to handle 2G, 3G, and 4G commercial frequencies that operate in a range from 700 to 2500 MHz, as well as publically safe UHF and VHF frequencies (150 and 450 MHz band channels). A DAS network can also be configured to support numerous Wi-Fi access points.
DAS networks are designed for several types of structures:
- Offices/Corporate Campuses
- Retail/Shopping Malls
- Airports/Train Stations
- Hotels/Casinos/Convention Centers
- Sports Venues/Stadiums
- University Campuses
- Government Municipalities
The initial design of a DAS network is critical to ensure the best performance of the system. The first step of a DAS design is to use an up-to-date blueprint of the building. An architectural drawing is best; however, a fire exit map can also be used as a second option. The second step is to know all the relevant physical information related to the building and the potential RF blockage. An RF survey captures a true assessment of your existing coverage. Then the quantities and locations of the necessary DAS nodes can be mapped out. The cable plant design comes next; determining the best pathways and lengths for the fiber optic and UTP cables.
Other design considerations:
- Plan for growth and provide for easy expansion and flexibility
- Performance of one DAS should not negatively affect the performance of another DAS
- Know the limits of DAS and do not exceed them
- Use quality components that meet design specs
And, most importantly, use highly skilled technicians to install and certify the entire DAS cabling infrastructure. (That’s us!)
For information on DAS networks, please contact Bill Roberts at firstname.lastname@example.org, or call us at 1-800-367-7472.