On the Capacity of Gaussian Multiple-Access Wiretap Channels with Feedback

Two-user Gaussian multiple-access wiretap channel models with feedback are investigated. First, we show that the secrecy capacity regions of both the Gaussian multiple-access wiretap channel (GMAC-WT) with feedback and the GMAC-WT with noncausal channel state information at the transmitters (GMAC-WT-NCSIT) and feedback equal the capacity region of the Gaussian multiple-access channel (GMAC) with feedback and without the secrecy constraint and the state corruption. Next, we derive inner and outer bounds on the secrecy capacity region of the GMAC-WT with degraded message set and feedback. Our numerical results show that the perfect secrecy of the private message can be achieved without loss of any reliable transmission rate.