Achieving vertices of the capacity region of the synchronous Gaussian correlated-waveform multiple-access channel with decision-feedback receivers

We consider users operating synchronously on a correlated-waveform multiple-access (CWMA) channel with additive Gaussian noise. CWMA is a multiple-access scheme where the users are assigned signature waveforms; it subsumes both orthogonal signaling (e.g., TDMA) and identical-waveform signaling (as in the conventional Gaussian multiple-access channel (C-GMAC)) as special cases. We obtain a decision-feedback receiver (DFR) for the CWMA channel which, in spite of its lower complexity than the optimal receiver, achieves the vertices of the CWMA channel's capacity region, implying in addition that the users can choose their single-user codes independently of each other. This result generalizes the well known successive decoder of the C-GMAC.