Distributed Antenna Systems are internal strategically placed small dome or panel antennas around the size of a smoke alarm that distribute a radio frequency signal which is gained from an external antenna directed at a telecommunications tower.
In-Building Coverage is gained by placing an external donor antenna directed at a telecommunications base transceiver station. The donor will draw frequency from the BTS and feed it into a Cel-Fi repeater system which then distributes it evenly across the internal antennas within the building.
A Cel-Fi Booster is used to repeat the gained radio frequency bands which have been drawn from the external area of the building. Each Cel-Fi repeater is distributing different frequencies being either 3G or 4G and also different service providers being Telstra, Optus or Vodaphone.
Each Cel-Fi system consists of two units. The Network Unit is placed in the area where the strongest native signal can be received from the carrier network (signal levels as low as -120 dBm are acceptable). The Network Unit comprises a transmitter and receiver which communicates with the cell tower. The Coverage Unit is placed in the center of the home, communicates wirelessly with the Network Unit and “lights up” the interior of the house with significantly enhanced signal levels, thus enabling better quality calls and greater data throughput.
Cel-Fi meets the newer regulatory requirements that allow a booster to be used (boosters that do not meet these requirements, which is the vast majority of them, are no longer legal). For the FCC you can learn more by reading the new FCC Report and order for signal boosters. According to these new regulations, consumers must receive permission from their carrier before using a booster. Consumer boosters sold after March 1, 2014, and some before that date will be marked with a label signifying it meets the FCC’s new regulations.
The radius (half the width) of the coverage bubble is approximately the distance between the Coverage Unit and Network (window) Unit. Here are some examples: