(Distributed Antenna System)
A setup where multiple small, low-power cellular antennas are placed throughout a structure or dense urban area that would normally be challenging to cover evenly and reliably with one large antenna. The antennas are connected to one base station (tower) and act as one base station, but with more even, reliable coverage than a traditional base station.
See: Base Station
One traditional base station outside of a very large building might provide poor coverage in the center and/or far side of the building. Alternatively, a DAS with antennas spread through the building could provide better coverage for those indoors. A DAS replacing a traditional base station improves coverage, but not capacity.
A DAS might deployed in the various halls of a large convention center, throughout a large office building, or in the stations and passageways of a subway system.