概率译码转发中继系统中的安全极化编码方法

Secrecy Polar Coding in Systems with Probabilistic DF Relay

该文针对中继节点依概率辅助译码转发的通信场景,提出一种中继辅助的安全极化编码方法,保证私密信息可靠传输的同时,达到提高安全传输速率的目的。首先,发送端分别进行两层极化编码——中继概率转发行为构成的虚拟二进制删除信道下的极化编码和实际传输信道下的极化编码,并将私密信息分别隐藏在两层码字中,分时隙广播出去。然后,中继依概率译码后提取出合法用户无法直接接收的固定信息再次进行安全极化编码并转发。最后,接收端利用收到的中继转发码字和发端码字依次分层进行译码。理论和仿真分析证明,所提方法下合法用户能够可靠接收私密信息,而窃听者无法获取任何私密信息信息量;安全传输速率随着码长和中继转发概率的增加而增大,且高于一般的安全极化编码方法。

A relay aided secrecy polar coding method is proposed for the communication systems where the relay uses Decode-and-Forward （DF） in probability. It ensures the transmission reliability and improves the secrecy rate. First, the transmitter encodes the secrecy bits in two layers： the first layer is designed over the virtual Binary Erasure Channel （BEC） that generated by the probabilistic DF relay, and the second layer is designed over the real transmission channels. After receiving the codeword, relay decodes and extracts the frozen bits which the legitimate user can not obtain directly in probability, and re-encodes them by classical secrecy polar coding. Finally, the receiver decodes the received codewords from the relay and the transmitter in turn. The theory and simulation results verify that the legitimate user is able to decode reliable, while the eavesdropper can not obtain any information about the secrecy bits. Moreover, the secrecy rate increases as the code length and the relay forwarding probability increase, and it outperforms the classical secrecy polar coding method.