Investigation of MIMO Channel Characteristics in a Two-Section Tunnel at 1.4725 GHz

This paper presents results from a wide band single-input-single-output (SISO) and 16 x 16 virtual multiple-input-multiple-output (MIMO) measurement campaign at a center frequency of 1.4725GHz in a 100-meter long tunnel laboratory which is terminated by a vertical wall with a metallic door. The path loss, root-mean-square delay spread (RMS-DS) characteristics, and power delay profiles (PDPs) are described. In addition, we provide results for the MIMO channel amplitude matrix, which offers a new perspective in understanding MIMO characteristics in tunnel scenarios. Our measurement results are analyzed and compared to ray tracing simulations. The relationships among the angle spread, channel matrix singular values, and MIMO capacity at various link distances are illustrated, and these provide insights into MIMO system deployment.