Impact of Feedback Errors on the Security of MIMO Wiretap Systems with Antenna Selection

This paper analyzes the impact of feedback errors on the security performances of multiple-input multiple-output (MIMO) wiretap channels. For the legitimate MIMO system, two schemes are considered: (1) transmit antenna selection/maximal ratio combining (TAS/MRC) and (2) transmit antenna selection/receive antenna selection (TAS/RAS). The eavesdropper uses either MRC or RAS techniques. We assume that both legitimate and eavesdropper receivers have the knowledge of their own channel state information. Furthermore, we consider that the index of the transmit antenna with the strongest signal-to-noise ratio is fed back from Bob to Alice. We derive closed-form expressions for the exact secrecy outage probability (SOP) and the probability of strictly positive secrecy capacity in Nakagami-m flat fading. In order to obtain the secrecy diversity order and the secrecy array gain, an asymptotic SOP expression is also derived.