On the existence of the Mazo-limit on MIMO channels

In English Mazo, in 1975, showed that the signaling rate of a linear modulation can
be significantly higher than the maximum rate for orthogonal signaling
without any loss of minimum square Euclidean distance. In subsequent
literature the highest such rate is referred to as the Mazo-limit. In this
letter we ask whether there exists a Mazo-limit also on
MIMO channels. The answer is yes, but it applies to the largest
pairwise error probability rather than to minimum square Euclidean distance. Moreover, it
occurs at exactly the same rate as in the AWGN case. As a special case
results for single-input single-output fading channels are obtained.