On Achievable Regions of Public Multiple-Access Gaussian Watermarking Systems

A public multiple-access digital watermarking system is studied, in which two correlated Gaussian covertexts are watermarked independently and then sent to one authorized receiver via memoryless Gaussian attack channels. Given two distortion level pairs (D1,D2) and (D′ 1,D ′ 2) with respect to the average squared error distortion measure, an achievable region is given in single-letter information quantities. An example is also utilized to illustrate the gain of correlated sources over uncorrelated sources.