New Bounds for the Capacity Region of the Finite-State Multiple Access Channel

The capacity region of the Finite-State Multiple Access Channel (FS-MAC) with feedback that may be an arbitrary time-invariant function of the channel output samples is considered. We provided a sequence of inner and outer bounds for this region. These bounds are shown to coincide, and hence yield the capacity region for two cases of FS-MACs: 1) when the state process is stationary and ergodic and not affected by the inputs; 2) an indecomposable FS-MAC without feedback. Though the capacity region is “multi-letter” in general, our results yield explicit conclusions when applied to specific scenarios of interest.