Wiretap channel with finite-rate feedback

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. This paper provides a survey of recent research on physical-layer security considering 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 start by introducing the classical notion of secrecy capacity. Then we show how finite-rate feedback degrades the secrecy capacity.