4.9 Repeaters for Rail Solutions
Rail coverage of passenger trains is a priority for many mobile operators, and as the rise in business travel via rail services increases, so does the demand for a good wireless service onboard trains.
However, it is a challenge for mobile operators to provide the sufficient signal and dominance needed to maintain high data services inside trains, sometimes even to provide basic voice services. Even if base stations are deployed at frequent intervals along the train line, or if the mobile operator relies on an outdoor DAS along the rail track (for more detail on Outdoor DAS refer to Chapter 12) the problem remains to get sufficient RF penetration through the train in order to service the users inside the train carriage.
Issues with penetration losses arise mainly from the fact that the train itself is a long metal tube, and modern trains even have metallic coating on the windows (see Section 11.2 for more detail).
Often the mobile operator has only one way to solve this issue, and that is to install an on-board repeater on the train that can compensate for the loss in the train.
The next chapter will highlight some of the many issues related to this challenge, of installing a repeater and DAS onboard a train.
4.9.1 Repeater Principle on a Train
Repeaters in general are a challenge, most of the concerns have been covered in the previous chapter, but one must realize that when deploying a mobile repeater solution onboard a train it all becomes even ...