Secrecy Capacity Scaling With Untrustworthy Aggressive Relays Cooperating With a Wire-Tapper
Michael Atallah, Georges Kaddoum · IEEE Wireless Communications Letters · 2016
In this letter, we investigate the performance of the secrecy capacity in an amplify-and-forward dual-hop network for both distributed beamforming (DBF) and opportunistic relaying (OR) techniques. We derive the capacity scaling for two sets; U untrustworthy aggressive relays cooperating together with a wire-tapper to intercept the message, and T trustworthy relays, for a large number of nodes. We prove that the capacity scaling in the DBF is bounded by a value depending on a ratio between the number of the trustworthy and the untrustworthy aggressive relays. Finally, we show that DBF is better than OR whose capacity scaling is proved to be upper-bounded by a value tending to zero when the untrustworthy relays are aggressive. Simulation results confirm our analytical derivations.