Secure Polar Coding With REP and XOR Coding

In this letter, we study the secure data communication by polar coding. In polar coding, all bit-channels perfectly polarize when the codelength goes to infinity. With finite and practical codelength, however, many bit-channels do not perfectly polarize and this significantly degrades the secrecy rate. To address this issue, we propose to use repetition (REP) coding and exclusive-or (XOR) coding combined with polar coding. To make the proposed approach practical, we develop simple design methods for REP and XOR codings. Numerical results demonstrate that the proposed secure polar coding improves the secrecy rate and security gap considerably.