Bounds on the capacity region of a class of multiple access interference channels

In this paper, we establish an approximate capacity region for a class of multiple access interference channels consisting of a multiple-access channel (MAC) and a point-to-point (P2P) link that are mutually interfering but in which there is interference only from one of the transmitters of the MAC to the receiver of the P2P link, known henceforth as the partially connected multiple-access interference channel, or simply as PMAIC. It is shown that for semi-deterministic PMAICs, single-user coding at the first transmitter of the MAC and H-K superposition coding at the second transmitter of the MAC and the transmitter of the P2P achieves a rate region that is within a quantifiable gap of the capacity region, thereby generalizing the result by Telatar and Tse for the 2-user semi-deterministic interference channel. Applying this result to the scalar Gaussian channel, we derive bounds on its capacity region within one bit, which can be seen as an extension of the work by Etkin et al for the Gaussian interference channel.