TR2003-043

Measurement of Keyhole Effect in a Wireless Multiple-Input Multiple-Output (MIMO) Channel
Citation: Almers, P.; Tufvesson, F.; Molisch, A.F., "Measurement of Keyhole Effect in a Wireless Multiple-Input Multiple-Output (MIMO) Channel", IEEE Communication Letters, ISSN: 1089-7798, Vol. 7, Issue 8, pp. 373-375, August 2003 (IEEE Xplore)
Date:July 2003
MERL Contact:Andreas F. Molisch

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 letter, we present the (to our knowledge) first measurement of this effect. The measurements are done in a controlled indoor environment, with transmitter and receiver in two adjacent rooms. One of the rooms is shielded, and propagation to the other room can occur only through a hole or a waveguide in the wall. We find that only the waveguide leads to an unambiguous keyhole, while a hole of the same size still allows multimodal propagation. Measurement of amplitude statistics also confirm theoretical predictions.

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