Correlated Sources over a Noisy Channel: Cooperation in the Wideband Limit

This paper studies cooperation between transmitters in a two-user Gaussian multiple access channel (MAC) with correlated sources in the wideband limit. The paper's findings can be intuitively stated as follows: if the two sources are sufficiently (highly) correlated, then full cooperation between the transmitters is possible in the wideband limit incurring an arbitrarily small bit error rate. The core idea behind this paper is to use pulse-position modulation and to allow signals from the two transmitters to coherently combine with one another. This result also emphasizes the difference between bit-error and block-error rates. Whereas cooperation is very difficult to establish when achieving arbitrarily small block error rates, it can be enabled when the objective is to achieve arbitrarily small bit error rates and the sources are highly correlated.