A distributed antenna system is a way to extend the coverage of a given network such as a cellular network or wireless computer network. All of the antennas are spaced from each other in such a way that each one is able to give full coverage without much overlap with the coverage areas of other antennas, minimizing the number of antennas required to cover a specific area.

All of the antennas in a DAS are simply extenders for signal coverage and are all connected to a central controller that, in turn, is connected to a carrier's base station. The RF spectrum covered by a DAS is licensed to wireless carriers, so enterprises cannot deploy a DAS on their own and must always involve a carrier, making the deployment the most expensive phase of a DAS project.

A DAS can be either passive or active. A passive DAS simply takes wireless signals from an antenna and then runs them through "leaky" feeder cables that act as antennas all over the building; the signal leakage distributes the signals. An active DAS takes the wireless signals from an external antenna and passes them to other antennas through fiber cables while being boosted and amplified along the way.