Secrecy CPS Transmission Scheme for Slow Fading Independent Parallel Wiretap Channels with New SOP Constraint

Abstract

This paper concerns the problem of secrecy transmission on slow fading parallel wiretap channels, where a transmitter Alice wants to transmit messages to an intended receiver Bob with an illegitimate receiver Eve eavesdropping on these messages. The channels are modeled as independent Parallel Rayleigh fading channels, and the coding per sub-channel (CPS) scheme is used with distinct encoders for each sub-channel. Moreover, the channel state information (CSI)concerning Bob is assumed to be perfectly known, while only the probability density function (PDF) of the CSI concerning Eve is available since Eve is usually a passive receiver. We aim to maximize the sum of secrecy rates with the CPS scheme under the constraint of secrecy outage probability (SOP). To this end, we propose a new average SOP which is a weighted sum of all the SOP for each sub-channel, and a secrecy rate maximization (SRM) problem is formulated under the constraint of SOP. Since this SRM problem is not convex and difficult to solve, three suboptimal solutions are proposed which improves the secrecy rate step by step. Numerical results show that the new SOP constraint is beneficial to improve the secrecy rate compared to the conventional one.