  We present the statistical characterization of a 2x2 Multiple-Input
Multiple-Output wireless link operated in a mode-stirred enclosure, with
channel state information available only at the receiver (agnostic
transmitter). Our wireless channel measurements are conducted in absence of
line of sight and varying the inter-element spacing between the two antenna
elements in both the transmit and receive array. The mode-stirred cavity is
operated: i) at a low number of stirrer positions to create statistical
inhomogeneity; ii) at two different loading conditions, empty and with
absorbers, in order to mimic a wide range of realistic equipment level
enclosures. Our results show that two parallel channels are obtained within the
confined space at both the operating conditions. The statistical
characterization of the wireless channel is presented in terms of coherence
bandwidth, path loss, delay spread and Rician factor, and wideband channel
capacity. It is found that the severe multipath fading supported by a highly
reflecting environment creates unbalance between the two Multiple-Input
Multiple-Output channels, even in presence of substantial losses. Furthermore,
the channel capacity has a multi-modal distribution whose average and variance
scale monotonically with the number of absorbers. Results are of interest in
IoT devices, including wireless chip-to-chip and device-to-device
communications, operating in highly reflective environments.
