Abstract:

It has been predicted theoretically that for some environments, the capacity of wireless MIMO systems can become very low even for uncorrelated signals; this effect has been termed keyhole or pinhole. In this paper the first unique measurements of this effect are presented. The measurements were performed in a controlled indoor environment that was designed to obtain a keyhole. We analyze limitations for measurement-based capacity calculations and keyhole investigations. We further present error bounds for the capacity and eigenvalue distributions due to measurement imperfections such as finite signal-to-noise ratio and multipath leakage. The bounds are compared to the measurement results and show excellent agreement. Finally, we analyze the envelope distribution and, as expected from theory, if follows a double Rayleigh.