The Composite Channel Method: Efficient Experimental Evaluation of a Realistic MIMO Terminal in the Presence of a Human Body

The immediate environment of the transmit (TX) and receive (RX) antennas, including the antenna casings and the users holding the antennas, has a strong impact on the propagation channel and thus on wireless systems. In this paper we experimentally evaluate a method that synthetically combines double-directional measurements of the propagation channel (without the user influence) with measured antenna patterns of antennas-plus-users, by comparing obtained sample results with direct measurements in the same environment. The measurements are done for a static microcell 8times4 MIMO scenario at 2.6 GHz. A realistic user phantom was used together with a test terminal prototype with four antenna elements, and a number of different configurations and orientations of the phantom were tested. In average over all test cases, the mean signal power deviation between composite channel method and measurements was well within 1 dB. The composite method shows 6% higher terminal antenna correlation but similar statistical distributions as the measured. The differences between the model and measurements for the strongest eigenvalue (relevant for MRC combining) was found to be within 1 dB above 10% outage level. Relative deviations in the ergodic MIMO capacity were smaller than 10%.