Secrecy Transmission Scheme Based on 2-D Polar Coding Over Block Fading Wiretap Channels

This letter discusses a secrecy transmission scheme based on 2-D polar coding over block fading wiretap channels. Unlike the previous approaches using 1-D polar coding, we propose to encode the secret bits in two dimensions to adapt to variation of the instantaneous secrecy capacity. In the proposed scheme, intra-block coding in one dimension is used to guarantee reliability, and cross-block coding in the other dimension is used to combat eavesdropping. Theoretical analysis demonstrates that our scheme is able to achieve the maximum perfect secrecy rate asymptotically. Simulation results show that the equivocation rate of eavesdropper is close to the secrecy capacity of the system with finite codelength.