Performance of space time coding in subway tunnel environments

We investigate how to increase the capacity of GSM (global system for mobile communications) radio interfaces in a subway tunnel environments by means of antenna arrays and space-time coding (STC) techniques. We demonstrate that the wireless channels encountered in subway tunnels behave as flat fading channels with strong spatial correlations. We also analyzed the performance of several STC techniques that do not introduce spatial correlation and, thus, maximize transmission rate. These techniques are evaluated with experimental channels measured in the subway of Paris.