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