Indoor LOS MIMO Channel Measurements with a Focus on Antenna Array Design

The bandwidth efficiency of Multiple Input - Multiple Output (MIMO) channels with different antenna arrays is analyzed. MIMO channels with a strong and unobstructed line-of-sight (LOS) signal component are considered, as it is the case in indoor in-room scenarios. The bandwidth efficiency of such channels is strongly dependent upon the applied antenna array and its orientation. Simulations of the pure LOS channel without multipath components are carried out to demonstrate this effect. So called polyhedron antenna arrays with antenna elements mounted on the faces of a regular polyhedron as well as the MIMO Cube deliver a bandwidth efficiency that is almost invariant from rotations of the antenna arrays. The measurement results verify this result. Polyhedron arrays appear to be a good alternative for MIMO systems, as the measured bandwidth efficiency of a polyhedron array is comparable to this of an uniform linear array (ULA), while the standard deviation is reduced to a large extend.