Indoor coverage – How it works in short.

Blog Published 2017-06-15

As we become more dependent on wireless communications our expectations on coverage increase, regardless of our location. This development places higher demands on service providers as well as individual property owners.

We have all experienced bad cell service inside an elevator or lack of Wi-Fi somewhere at work. Modern buildings are highly insulated to be energy efficient, unfortunately also isolating them from incoming radio signals. Ironically, about 80% of mobile phone calls are placed indoors, so it is not hard to understand that coverage often needs reinforced inside shopping malls, in arenas, in tunnels, etcetera.

The basic principles of extending coverage (indoors) are almost identical regardless of wireless technology, even if the radio signals ability to penetrate obstacles differ. So whether it be GSM, LTE, Wi-Fi or two-way radio the same type of equipment is used, although they may be named differently.

Signal source

Base station

A base station is a central part of any network and is directly connected to the systems core. Large, crowded buildings can besides lacking coverage also exceed the local capacity of the mobile network, probably requiring an additional base station to be set up.

In addition to providing a new or larger coverage area the base station also provides additional “communication paths” and therefore can manage an increased number of simultaneous calls or data transfers. I.e. The total capacity has been increased.

Repeater

As the name suggests a repeater simply repeats incoming signals. This means that unlike a base station the repeater only increases the coverage area of the base station it is connected to. It does not affect the number of simultaneous calls or transfers that can be placed.

A repeater is the most common and cost-effective method to locally expanding the coverage area. They are available two main types, off-air and fibre-fed. They are available for repeating either single or multiple signals. Multi-signal versions are often called MIMO (multiple input-multiple output) and are for instance used to extend the coverage area for several different service providers in the same equipment.

Off-air repeater

An off-air repeater wirelessly receives the signal from the source (base station), amplifies it internally and re-distributes it through its own antenna system.

Fibre-fed repeater

A fibre-fed repeater is directly connected to the base station via a cable, from which it receives the signal. It then amplifies and distributes the signal through its own antenna system.

Distributed Antenna Systems (DAS)

Basically a network of separate antennas connected to the same source and providing wireless coverage in an area or building.

Instead of “single-point antennas”, a special cable know as leaky cable can be used. Like an irrigation hose with a hole pattern the leaky cable lets through radio signals to provide wireless coverage in primarily tunnels and culverts.

Before you start building indoor coverage

Inappropriate and/or badly optimised equipment can cause more or less serious interference. Interference that can affect service level both locally but also in the larger network. So make sure you always have approval from the network owner (service provider) and/or regulatory agency. Also ensure you work with a capable and experienced supplier when developing your indoor coverage. Regardless of technology.