Achievable Regions and Precoder Designs for the Multiple Access Wiretap Channels With Confidential and Open Messages

This paper investigates the secrecy achievable region of multiple access wiretap (MAC-WT) channels where, besides confidential messages, users have also open messages to transmit. All these are intended for legitimate receiver (or Bob brevity) but only need be protected from eavesdropper (Eve). We first consider a discrete memoryless (DM) MAC-WT channel where both and Eve jointly decode their interested messages. By using random coding, we find an rate region, within which perfect can realized, i.e., all communicate with arbitrarily small probability error, while information leaked tends zero. Due high implementation complexity joint decoding, DM simply decodes independently still applies decoding. then extend results in case Gaussian vector (GV) channel. Based on theoretic results, further maximize sum GV system by designing precoders users. Since problems non-convex, provide iterative algorithms obtain suboptimal solutions. Simulation show that compared existing schemes, secure communication greatly enhanced proposed algorithms, contrast works focus network performance, spectrum efficiency effectively improved since simultaneously transmitted.