Theoretical and experimental analysis of the channel capacity enhancement based on MIMO techniques in subway tunnels

Both a theoretical approach and measurements of channel characteristics have been carried out to determine the maximum capacity which can be expected when MIMO techniques are implemented in tunnels, and especially in subway tunnels. Emphasis is given to the influence of the position of the antennas inside the transmitting and receiving arrays on the correlation between paths and on the singular values of the transfer matrix. The channel capacity is given for various geometrical configurations and compared with the case of i.i.d. Rayleigh channels.