  The goal of this paper is to provide a rigorous information-theoretic
analysis of subnetworks of interference networks. We prove two coding theorems
for the compound multiple-access channel with an arbitrary number of channel
states. The channel state information at the transmitters is such that each
transmitter has a finite partition of the set of states and knows which element
of the partition the actual state belongs to. The receiver may have arbitrary
channel state information. The first coding theorem is for the case that both
transmitters have a common message and that each has an additional common
message. The second coding theorem is for the case where rate-constrained, but
noiseless transmitter cooperation is possible. This cooperation may be used to
exchange information about channel state information as well as the messages to
be transmitted. The cooperation protocol used here generalizes Willems'
conferencing. We show how this models base station cooperation in modern
wireless cellular networks used for interference coordination and capacity
enhancement. In particular, the coding theorem for the cooperative case shows
how much cooperation is necessary in order to achieve maximal capacity in the
network considered.
