Secure Communication Over Parallel Relay Channel
The authors investigate the problem of secure communication over parallel relay channel in the presence of a passive eavesdropper. They consider a four terminal relay-eavesdropper channel which consists of multiple relay-eavesdropper channels as sub-channels. For the discrete memoryless model, they establish outer and inner bounds on the rate-equivocation region. The inner bound allows mode selection at the relay. For each sub-channel, secure transmission is obtained through one of two coding schemes at the relay: decoding-and-forwarding the source message or confusing the eavesdropper through noise injection. For the Gaussian memoryless channel, they establish lower and upper bounds on the perfect secrecy rate.