Multiuser bi-directional communications in cooperative relay networks

In this paper, we extend the concept of the one-directional multiuser peer-to-peer amplify-and-forward relaying scheme to that of a bi-directional two-phase relaying scheme. The relay weights are chosen to maximize the minimal received quality-of-service of all the users under constraints on the individual and the total power at the relays. The computation of the relay weights is accomplished by approximately solving a non-convex optimization problem using a sequential convex programming algorithm of low complexity. In our simulations, the proposed bi-directional relaying scheme outper-formed the one-directional multiuser peer-to-peer scheme.