A distributed antenna system (DAS) is a system designed to extend the coverage of typically outdoor wireless services, such as cellular, private radio systems, public safety radios, etc., but can also be used for indoor wireless services, such as Wireless LANs. The penetration of these services in buildings varies according to their frequency and power, but it is generally difficult for an outside signal to cover a large space inside a building. A distributed antenna system can function as a repeater or can be used to provide a complete infrastructure for wireless services.
A distributed antenna system is a connected network of antenna sites called nodes that provide wireless service within a geographic area or structure. Individual antennas are typically mounted on top of power or utility poles, in secure cabinets, or on roofs.
Given that DAS originated within the cellular industry, it should come as no surprise that this is also where they are currently most effective. The current common use of a distributed antenna system is to extend coverage in the cellular industry for both voice coverage and data coverage. Other applications are on the horizon for these systems, such as building management, energy management, physical and other security, and even WLAN provisioning are just a few examples of this growing market.
In some areas, the use of a distributed antenna system just makes sense. For example, in the health care industry, areas such as operating rooms must remain sterile, so maintenance of equipment in rooms or installation of new equipment can cause disruptive outages. The DAS must be installed when the hospital is built or is undergoing renovation. The same can be said for laboratory areas, where precision measurements and tests require a clean room.
Another use for a distributed antenna system would be in a high security area with restricted access. Encryption and authentication methods in these areas generally go beyond AES and 802.1X, such as FIPS 140-2 and there are also encryption standards for classified Top 10 Echo . DAS can work in these areas carrying WLAN traffic only for authorized personnel.