Capacity of the K-user discrete memoryless multiple access channel with common information and with or without state

An explicit and efficient capacity characterization of the K-user discrete memoryless multiple access channel with common information and discrete memoryless state is provided. Messages are indexed according to which transmitters are aware of the messages, and any of 2^K-1 possible such messages may exist. A superposition coding scheme, which generalizes the approach taken by Slepian and Wolf for the two-user case without state, achieves this capacity region. When there is state, a separable coding scheme suffices to attain capacity.