Artificial noise aided polar codes for physical layer security

The secrecy rates of the existing practical secrecy coding methods are relative low to satisfy the security requirement of 5G communications. We propose an artificial noise (AN) aided polar coding algorithm to improve the secrecy rate. Firstly, a secrecy coding model based on AN is presented, where the confidential bits of last transmission code block are adopted as AN to inject into the current codeword. In this way, the AN can only be eliminated from the jammed codeword by the legitimate users. Since the AN is shorter than the codeword, we then develop a suboptimal jamming positions selecting algorithm with the goal of maximizing the bit error rate of the eavesdropper. Theoretical and simulation results demonstrate that the proposed algorithm outperforms the random selection method and the method without AN.