A Distributed Antenna System (DAS) improves wireless coverage in buildings by connecting a network of antennas to a central signal source.
In its most simplified form, a DAS has two basic components:
1 - A signal source
A Distributed Antenna System, as the name implies, “distributes” signal. But it generally doesn’t generate the cellular signal itself. A DAS needs to be fed signal from somewhere. Whether it's 4G LTE or 5G, there are four typical signal sources: off-air (via an antenna on the roof), an on-site BTS (Base Transceiver Station), and finally the newest approach: small cells.
2 - Distribution system
Once received, the cellular signal must be distributed throughout the building. There are four main types of distribution systems: active (using fiber optic or ethernet cable), passive, hybrid, and digital.
A distributed antenna system’s performance depends on the type of technology it uses. To understand what we mean by “performance,” we first need to understand the two main performance metrics: coverage and capacity.

