There are three options to set up radio coverage indoors:
Which of these three is the best choice for a transportation company?
DMO alone cannot provide reliable and stable radio coverage for a building or in a tunnel. Radio coverage depends on the users’ locations so it is unpredictable. In addition, losses apply to both ends, which reduces the range of radio coverage.
A cell-enhancer will only repeat a signal coming from an outdoor base station. That base station will have to handle additional traffic from the users inside the building. This eats up its capacity. Cell-enhancers may also interfere with the main cell.
When building radio coverage, the trick is to balance the uplink - traffic from a radio terminal to the base station - and downlink - from a base station to the radio terminal. The uplink is more critical, so a base station should have significantly better than average uplink connection. The better coverage with fewer base stations helps cut costs.
Setting up a network in difficult locations such as tunnels can be challenging. Sensitive, powerful base stations with low power consumption and small physical size are important. It must also be possible to operate and maintain them remotely.
While regular RF repeaters are an option for tunnels, a miniature base station can be so much better. The TB3p and TB3hp mini base stations
If you thought that a more powerful PMR radio enjoys better radio coverage, you should read this blog post: Do you know the secret of Watts in your PMR radio? (Nobody else will tell you.)