Polar Coding for the Multiple Access Channel With Confidential Messages

The multiple access channel with confidential messages (MAC-CM) generalizes the traditional multiple access channel by allowing both users to receive channel outputs. Achievable secrecy rate region of this model has been established using random coding arguments, whereas practical codes design remains to be further discussed. In this paper, we develop an explicit polar coding scheme that achieves the secrecy rate region of the MAC-CM under strong secrecy. In particular, our scheme mainly relies on monotone chain rules and polar coding techniques for single-user channels. A proper chaining scheme is constructed to align polar indices and to provide strong secrecy. Finally, a rigorous analysis is provided to validate the performance of our scheme.