Source Coding Rate Allocation in Orthogonal Compress-and-Forward Relay Networks

The source coding rate allocation problem for the orthogonal multiple-access relay channel with M users and compress-and-forward at the relay is addressed. In case of Gaussian codebooks at the sources and Gaussian channels, we show that the sum-rate-optimal assignment of source coding rate at the relay is given by waterfilling. For general modulation alphabets at the sources and finite-alphabet discrete memoryless channels, the source coding rate allocation problem is formulated using the information bottleneck method, based on which we appropriately modify a standard cutting-plane algorithm to numerically compute an optimal source coding rate vector at the relay.