On the multiway relay channel with direct links

This paper studies the extension of the multiway relay channel model with restricted encoders (introduced by Gündüz et al.) by adding unit-gain intra-cluster links. In this model, multiple clusters of users communicate with the help of one relay and the users within a cluster wish to exchange messages among themselves. We obtain achievable rates and gaps to the cut-set bound as a function of the number of users and the cluster-to-relay gain g.