70GHz mmWave Track to Train Communications - Tunnel Validation

The migration to future <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5 \mathrm{G} / 6 \mathrm{G}$</tex> communication to trains requires high bandwidth and low-cost technologies. In this paper we present a 70 GHz mmWave track-to-train communications technology that is in commercial use today and ready for tomorrow. The application to in-tunnel coverage is studied via a field trial in an arched railway tunnel in the UK. Results demonstrate that connectivity through the tunnel can extend up to a range of nearly 1 km with continuous coverage for over 700 m. Furthermore, the multipath rays reflected from the tunnel walls, floor and ceiling can be exploited to provide enhanced coverage around curves.