Experimental Assessment of the Channel Capacity in Indoor MIMO Systems Using Dual-Polarization

In multiple-input multiple-output (MIMO) systems, orthogonal polarization is utilized to achieve small mutual coupling and low spatial correlation. We present the 4 times 4 MIMO channel measurements in the line-of-sight (LOS) environment in a small room. We reveal the difference of the channel capacity dependent on receiving positions by comparison of the vertical polarized antenna configuration (V) versus vertical and horizontal polarized antenna configuration (V/H). The position dependence of the received power, spatial correlation and eigen-values show that the dominant factor in the receiving positions achieving large channel capacity is changed according to the antenna configurations. This paper also provides that the channel capacity for V/H is larger than that of V at all the measured points, and is dominated by the decrease of the spatial correlation. We show that the channel capacity enhancement is small in the environment which direct wave is too dominant for V.