5.7 Multioperator Systems
Often there is a need for the indoor DAS to support multioperator configurations, where more than one operator or band is to share the same DAS. This will typically be the case in large public buildings, airports, convention centers and tunnels, where there is a need for high capacity and in many cases more than one type of mobile system on air over the same DAS, .
From an economic perspective there is much to be saved by the operators if they share the DAS. Seen from the building owner's perspective, it is also preferable to have only one DAS, one installation, one set of antennas, one project to coordinate and one equipment room.
In order to connect more operators to the same DAS, you need to combine several base stations, repeaters and bands into the same system. Combining the operators and bands into the same DAS is not a trivial issue; you need to pay close attention to many potential problems that might degrade the service if you are not careful.
The principle of the active DAS, where DL and UL are separated at the interface to the main unit, as well as the low power levels required at the input (typically less than 10 dBm), will ease the requirements and the design of the combiner. If considering a passive DAS for a multioperator solution, then the combiner becomes an issue. Be careful when combining several operators or bands at high power using ...