Lossy transmission of correlated sources over multiple‐access wiretap channels

In this study, the authors study lossy communication of correlated sources over a multiple‐access wiretap channel (MAC‐WT). Consider a system with two transmitters, a receiver and an eavesdropper. There are two correlated sources where each of them is observed by the corresponding transmitter, separately. Each transmitter wishes to describe its source sequence to the receiver with a desired distortion. The sources need to be kept secret from the eavesdropper. They find an achievable region for the MAC‐WT with correlated sources by separation. A joint source‐channel coding scheme for the MAC‐WT is also proposed. They consider lossy communication of a bivariate Gaussian source over Gaussian MAC‐WT (GMAC‐WT). They propose a separation‐based achievable scheme for the GMAC‐WT. An achievable region for the GMAC‐WT based on uncoded transmission is also found. They compare the separate and the uncoded schemes for the symmetric GMAC‐WT, where the same constraint on the power of each transmitter is imposed and the same distortion on each source is achieved. For another case of source correlation coefficient, they compare the separate, uncoded and hybrid schemes. They obtain outer bounds to the rate‐distortion‐equivocation region of: (i) the degraded MAC‐WT where the output at the eavesdropper is a degraded version of the output at the receiver, (ii) the GMAC‐WT with independent sources and (iii) the symmetric GMAC‐WT when the correlation of the sources is maximum. Optimal regions for some cases are established.