  The outage performance of multiple-input multiple-output (MIMO) technique has
received intense attention in order to ensure the reliability requirement for
mission-critical machine-type communication (cMTC) applications. In this paper,
the outage probability is asymptotically studied for MIMO channels to
thoroughly investigate the transmission reliability. To fully capture the
spatial correlation effects, the MIMO fading channel matrix is modelled
according to three types of Kronecker correlation structure, i.e., independent,
semi-correlated and full-correlated Rayleigh MIMO channels. The outage
probabilities under all three Kronecker models are expressed as representations
of the weighted sum of the generalized Fox's H functions. The simple analytical
results empower the asymptotic outage analyses at high signal-to-noise ratio
(SNR), which are conducted not only to reveal helpful insights into
understanding the behavior of fading effects, but also to offer useful design
guideline for MIMO configurations. Particularly, the asymptotic outage
probability is proved to be a monotonically increasing and convex function of
the transmission rate. In the absence of the channel state information (CSI),
the transmitter tends to equally allocate the total transmit power among its
antennas to enhance the system reliability especially in high SNR regime. In
the end, the analytical results are validated through extensive numerical
experiments.
