On the Capacity of Multiple-Access-Z-Interference Channels

The capacity of a network in which a multiple access channel generates interference to a single-user channel is studied. An achievable rate region based on superposition coding and joint decoding is established for the discrete case. If the interference is very strong, the capacity region is obtained for both the discrete memoryless channel and the Gaussian channel. For the strong interference case, the capacity region is established for the discrete memoryless channel; for the Gaussian case, a line segment on the boundary of the capacity region is attained. Moreover, the capacity region for the Gaussian channel is identified for the case in which one interference link is strong, and the other is very strong. For a subclass of Gaussian channels with mixed interference, a boundary point of the capacity region is determined. Finally, for the Gaussian channel with weak interference, sum capacities are obtained under various channel coefficient and power constraint conditions.