Physical Layer Secrecy Performance Analysis of Imperfect Feedback Based 4×1 MISO System

Abstract

In this paper, we analyze the physical layer secrecy performance of two-bit feedback based 4 × 1 multiple-inputsingle-output communication system in the presence of a single antenna equipped passive eavesdropper over Rayleigh faded channel. To achieve full-rate and spatial diversity real orthogonal space-time block code is employed in the considered wiretap communication system. In a practical wireless communication system, it is not always possible to acquire full channel knowledge. Thereby, in this paper, we exploit the partial channel state information at the transmitter with the help of two-bit quantized feedback based diagonal precoder. Further, exact closed-form expressions of the secrecy outage probabilities are derived over perfect and imperfect feedback bits by using order statistics. It is shown in the numerical results that an optimized power allocation scheme successfully improves secrecy performance gain under erroneous feedback in comparison to other schemes.