Site-specific indoor MIMO capacity using adaptive techniques

The paper investigates, for site-specific indoor scenarios, the attainable improvement of the MIMO capacity by using one or more radio frequency (RF) adaptive techniques. For a scenario-specific (4,4) MIMO system in a corridor, we predict the channel matrix between the transmit and receive ports through image ray tracing (IRT) simulations. We show results for different orientations of transmit/receive arrays and for various positions of the receive array. We demonstrate the dependence of the predicted MIMO capacity on the site-specific scenario over a range of receive end locations. In various specific situations, adaptive techniques can enhance capacity only to a certain extent depending on the original channel matrix. The normalized singular values demonstrate that the capacity enhancement is due to better use of the eigen channels. Combining more than one adaptive technique does not provide further capacity improvement.