The Norwegian Ministry of Transport is pushing to significantly improve mobile capacity and speeds across the country’s rail network and the Follo Line project, due to complete in 2021, is acting as a test bed to develop the technology. RFS worked with Telia, Telenor and Bane NOR to deploy in-tunnel infrastructure capable of delivering a mobile broadband connection. The deployment is geared towards delivering a Quality of Experience (QoE) that will allow passengers to use data intensive services with the aim of achieving 5 Mbps per user.
The testing was conducted inside a 20 km abandoned road tunnel in Holmestrand, Norway. Inside the tunnel, RFS deployed its RADIAFLEX radiating cables connected to a radio transmitter with 4G 4x4 MIMO capability. The 2x2 MIMO setup utilised a horizontally polarised radiating cable and a vertically polarised radiating cable. This doubled in the 4x4 MIMO setup.
The test achieved approximately 95 percent of theoretical maximum speeds for 4x4 MIMO in the tunnel. The results also demonstrate a 100% increase in download rates when going from SISO to 2x2 MIMO and an additional 100% increase in download rates from 2x2 MIMO to 4x4 MIMO.