ZF-SIC Based Individual Secrecy in SIMO Multiple Access Wiretap Channel

In this paper, a decoding method of joint zero-forcing and successive interference cancellation (ZF-SIC) is put forward to assist the study of the individual secrecy in the quasi-static Rayleigh fading single-input multiple-output multiple access wiretap channel. We first evaluate the individual secrecy performance by deriving the closed-form expressions in terms of positive secrecy capacity probability, secrecy outage probability, and effective secrecy throughput (EST). Besides the expected impact of the SIC order, we find, in high signal-to-noise ratio (SNR) regime, the secrecy performance is only determined by the transmitter’s relative distance to eavesdropper over legitimate receiver rather than the SNR. Such a result prompts us to propose an SIC order scheduling scheme (alternative scheme) on basis of the transmitters’ relative distances from the shortest to the longest. It is proved optimal in achieving total maximum EST in high SNR regime. Finally, we also investigate the problem of optimal power allocation to each transmitter under the constraint of the limited total power. An interesting solution to this problem is disclosed with the aid of numerical analysis.