Security-Reliability Tradeoff for Relay Networks in the Presence of Channel Estimation Error

In this work, a two-phase optimal-relay transmission scheme for relay networks against eavesdropper is proposed. The security and the reliability performance of this scheme are evaluated in the form of the intercept probability and the outage probability, respectively. In addition, the closed-form expression of security-reliability tradeoff (SRT) is obtained to show the compromise of the security and reliability performance of the system. Specifically, instead of common assumptions of perfect global channel state information in most literature, the channel estimation error and its effects on performance analysis are considered in this paper. It is shown that the security (or reliability) can be enhanced by degrading the reliability (or security) requirement, and the performance can be improved by increasing the number of relays. Finally, simulation results are provided to corroborate our proposed studies.