Secrecy Polar Coding Scheme for Relay-Wiretap Channel

In this paper, we propose a secrecy polar coding scheme for a relay-wiretap channel where a four-node configuration with a trusted relay node is applied under a decode-and-forward (DF) strategy. Based on the channel polarization phenomenon of polar codes, confidential information is sent to the relay and destination nodes using their good bit channels; random bits are fed to the good bit channels of the eavesdropper. By using two time slots, the destination node can recover the message from the source node while the eavesdropper cannot get any information about the message. The design eliminates the need for the source and the relay to have prior knowledge of the degraded eavesdropper channel in order to guarantee secrecy. The proposed method ensures the security of the transmitted confidential message. The simulation results indicate improvements in the coding rate and the bit error rate (BER) performance over existing techniques.