  While the impact of finite-rate feedback on the capacity of fading channels
has been extensively studied in the literature, not much attention has been
paid to this problem under secrecy constraint. In this work, we study the
ergodic secret capacity of a multiple-input multiple-output
multiple-antenna-eavesdropper (MIMOME) wiretap channel with quantized channel
state information (CSI) at the transmitter and perfect CSI at the legitimate
receiver, under the assumption that only the statistics of eavesdropper CSI is
known at the transmitter. We refine the analysis of the random vector
quantization (RVQ) based artificial noise (AN) scheme in [1], where a heuristic
upper bound on the secrecy rate loss, when compared to the perfect CSI case,
was given. We propose a lower bound on the ergodic secrecy capacity. We show
that the lower bound and the secrecy capacity with perfect CSI coincide
asymptotically as the number of feedback bits and the AN power go to infinity.
For practical applications, we propose a very efficient quantization codebook
construction method for the two transmit antennas case.
