A Versatile Secure Transmission Strategy in the Presence of Outdated CSI

We study secure transmission considering the practical scenario in which only outdated knowledge of the legitimate receiver's channel and statistical knowledge of the eavesdropper's channel are available at the transmitter. Conditioned on the limited channel knowledge, we adopt an on-off secure transmission scheme and propose a versatile strategy to determine the codeword transmission rate. We first analyze the outage performance of the system and then provide the design of optimal wiretap code parameters maximizing the secrecy throughput. Compared with the existing solution in the literature, the proposed secure transmission design enlarges the achievable reliability-security region and increases the maximum secrecy throughput.