Secrecy performance analysis for transmit antenna selection with outdated CSI

In this letter, we analyze the impacts of outdated channel state information (CSI) on the secrecy performance for multiple-input single-output multiple-eavesdropper (MISOME) systems using transmit antenna selection (TAS) scheme and derive the exact closed-form expressions for the secrecy outage probability and the probability of non-zero secrecy capacity. Then, we present the asymptotic secrecy outage probability which reveals the secrecy diversity order and the secrecy array gain. The analysis and simulation results show that the security performance of TAS scheme is quite sensitive to outdated CSI and the achievable secrecy diversity order is only one under the effect of outdated CSI.