On the Sum-capacity of Compound MAC Models with Distributed CSI and Unknown Fading Statistics

Multiple access with distributed channel state information (CSI) models several practical wireless communication scenarios where the individual transmitters glean their respective channel state information from downlink pilot symbols, typically in a Time Division Duplex (TDD) mode. When users are deployed in a field, as in sensor networks or vehicular networks, each transmitter is often unaware of the exact statistics of the fading coefficients, while it is known to be one among a set of possible distributions. In this paper, using the distributed CSI availability at the encoders and full CSI at the receiver of a fading Gaussian MAC, we design communication schemes achieving the compound sum-capacity, i.e. maximal sum-rate which can be supported irrespective of the set of encountered fading distributions. Models with and without power control are analyzed.