  This paper presents a detailed secrecy outage performance analysis of
correlated multi-antenna wiretap channels with three popular diversity
combining schemes, namely maximal ratio combining, selection combining, and
equal gain combining at the legitimate receiver. For single input multiple
output wiretap channels, both exact and asymptotic expressions are derived for
the secrecy outage probability (SOP) of these systems. The findings suggest
that, compared with the scenario where all the channels are independent,
correlation of the main channels alone increases the SOP by a factor of 1/
det(U), where det(U) is the determinant of correlation matrix U. In contrast,
in the high signal-to-noise ratio regime at the legitimate receiver,
correlation between the main channels and the eavesdropper channels has a
positive effect on SOP. Moreover, for multiple input and multiple output
wiretap channels, the SOP of two transmit antenna selection (TAS) schemes are
analyzed for the considered correlated channel model. The SOP relationship of
the both TAS schemes is quantified by the secrecy array gain. Finally,
numerical simulations are conducted to corroborate the analytical results.
