Distributed antenna systems (DAS) provide a convenient, power efficient way to move RF signals within buildings (iDAS or indoor DAS) or in outdoor places such as stadiums or venues (oDAS or outdoor DAS). A DAS consists of two main parts: a signal source and a distribution system. The signal source can be an outdoor antenna or a local base station.
The principle idea is this: to replace a single, high power antenna with several power efficient antennas without losing any area coverage. There are many types of distribution systems. The main idea for each system is to propagate the signals in such as way that maximum power and signal coverage is utilized. In one architecture, a master unit is connected to the base station using RF coaxial cable. The frequency of this energy is then increased to the optical range and carried using fiber optic cables to each remote unit on each floor of the building. The energy is then reduced down to the RF frequency and passive splitters are used to distribute the signals to each antenna. Architectures can be purely passive, purely active or a hybrid combination of both. DAS is advantageous for increased coverage but can result in higher costs due to increased infrastructure required.