Individual secrecy of fading homogeneous multiple access wiretap channel with successive interference cancellation

Abstract

We investigate individual secrecy performance in a K-user quasi-static Rayleigh fading homogeneous multiple access wiretap channel (MAC-WT), where a legitimate receiver employs successive interference cancellation (SIC) decoding. We first evaluate individual secrecy performance under an arbitrary SIC order by deriving closed-form expressions with respect to secrecy outage probability and effective secrecy throughput (EST) as main metrics. The resulting closed-form expressions disclose a significant impact on the secrecy performance from the order of SIC decoding. Therefore, we propose three SIC decoding order scheduling schemes: (1) round-robin scheme, absolutely fair and served as a benchmark; (2) suboptimal scheme, based on each user's main channel condition; and (3) optimal scheme, based on each user's achievable secrecy rate. Comparison results show that the last two schemes outperform the first one with regard to both the EST and the multi-user diversity gain, whereas the performance of the suboptimal scheme is highly close to that of the optimal scheme which is usually impractical due to a requirement for the eavesdropper's channel state information (CSI).

Jamming-Aided Secrecy Performance in Secure Uplink NOMA System

“…As pointed out in [6], [24], [37], the transmitters with bad channel qualities have bad secrecy performance in terms of EST even for a good SIC order, which enlightens us to switch these users into jammers to aid other users for improving their secrecy performance. We also care about which user(s) should be chosen as jammer(s) and how to allocate power to each user (including jammer(s)) so as to maximize the overall secrecy performance.…”

“…According to (4), (6) and 7, the positive secrecy rate probability of U k with the aid of jammers in set J can be formulated as…”

“…Yet, in the secrecy scenario of UL NOMA, such an SIC order does not necessarily obtain the most secrecy throughput. As pointed out in [6], on the contrary, the SIC order in ascending of signals' strength maximizes the overall secrecy throughput, in spite of further deteriorating the weakest users.…”

“…We later generalized the number of eavesdropper's antenna from single to multiple in [37], where a novel SIC order scheduling scheme was presented based on each user's relative distance to the eavesdropper over the legitimate receiver, in addition to the closed-form expressions of individual secrecy performance. We further examined the homogeneous fading MAC-WT [6], where secrecy scenarios can be found in satellite communications, and investigated the SIC order schemes from the perspective of the legitimate receiver. The studies in both [6] and [37] show the SIC order in ascending quality of each transmitter's channel achieves more overall secrecy performance at the cost of further deteriorating the secrecy performance of the transmitters with bad channel qualities.…”

“…We further examined the homogeneous fading MAC-WT [6], where secrecy scenarios can be found in satellite communications, and investigated the SIC order schemes from the perspective of the legitimate receiver. The studies in both [6] and [37] show the SIC order in ascending quality of each transmitter's channel achieves more overall secrecy performance at the cost of further deteriorating the secrecy performance of the transmitters with bad channel qualities.…”