Relaying for Multiuser Networks in the Absence of Codebook Information
This paper considers relay assisted transmission for multiuser networks when the relay has no access to the codebooks used by the transmitters. The relay is called oblivious for this reason. Of particular interest is the Generalized Compress-and-Forward (GCF) strategy, where the destinations jointly decode the compression indices and the transmitted messages, and their optimality in this setting. The relay-to-destination links are assumed to be out-of-band with finite capacity. Two models are investigated: the Multiple Access Relay Channel (MARC) and the InterFerence Relay Channel (IFRC). For the MARC with an oblivious relay, a new outer-bound is derived and it is shown to be tight by means of achievability of the capacity region using GCF scheme.