4.1 What Type of Distributed Antenna System is Best?
There are many different approaches to how you can design an indoor coverage system with uniformly distributed coverage level; passive distribution, active distribution, hybrid solutions, repeaters or even distributed Pico cells in the building. Each of these approaches have their pros and cons, all depending on the project at hand. One design approach could be perfect for one project, but a very bad choice for the next project – it all depends on the building, and the design requirements for the current project, and the future needs in the building.
Seen purely from a radio planning perceptive you should ideally select the system that can give the most downlink power at the antenna points and the least noise load and loss on the uplink of the base station, and at the same time provide uniform coverage and good isolation to the macro network. On top of the radio planning requirement, other parameters like installation time and costs, surveillance and upgradeability play a significant role. In practice the service requirements and the link budget (see Section 8.1.3) will dictate how much loss and noise you can afford and still accommodate the service level inside the building you are designing for.
4.1.1 Passive or Active DAS
Traditionally passive distributed antenna systems have been used extensively for GSM in the past 15 years. Therefore naturally many radio planners will see this as the first choice when designing indoor coverage ...