In-Building Radio Enhancement Systems for Public Safety

摘要

The purpose of public safety radio is to provide reliable communications over a jurisdiction. Industry standards recommend that 97 percent of a jurisdiction area have radio coverage. Unfortunately, because of building attenuation, this availability ends once public safety professionals enter buildings within the jurisdiction where a significant amount of their work lies. Building attenuation varies widely with the variety of construction materials, how the materials are used architecturally, the location of the building, type of building, and position within the building. It is particularly high in the lower floors of buildings in urban areas. A number of approaches have been used to overcome building attenuation such as reducing repeater coverage areas, enabling portable radios to bypass the repeater and talk directly to each other, and using mobile repeaters. However, the most reliable approach is to use an in-building radio enhancement system (IBRES). IBRESs circumvent building attenuation by guiding the signal between indoor and outdoor antennas over a robustly designed distribution network. Loss of radio coverage is virtually eliminated by the judicious placement of the indoor antennas. These systems are typically designed to provide coverage greater than 90 percent in most areas of the building and 95 percent in critical areas such as lobbies, stairs, and elevators.