MIMO channel measurement campaign in subway tunnels

The recent construction of the new L9 subway line in Barcelona, Spain has provided the opportunity to study the impact of different antenna configurations on the maximum channel capacity inside subway tunnels. In this work the authors present the design tradeoffs inside different kind of tunnels in terms of antenna spacing and applied diversity technique for a 2×2 MIMO system at C-Band. These design tradeoffs are the conclusion of the measurement campaign carried out during last year at L9 subway tunnels.