Optimal Resource Sharing and Network Beamforming for Bidirectional Relay Networks

We present a resource sharing scheme where two transceiver pairs share their resources in a collaborative manner. The two transceivers in each pair wish to communicate bidirectionally through several distributed relays. We assume that one of the pairs is the primary pair, meaning that it owns radio frequency spectrum resources and needs to be serviced with a minimum guaranteed rate. The other pair, called the secondary pair, is assumed to own the relay infrastructure. The secondary network allows the primary pair to use the relays in order to establish a bidirectional communication between its transceivers. In exchange for this cooperation, the primary pair assigns a portion of its spectral resources to the secondary pair, for setting up a two-way communication between the secondary transceivers. Assuming amplify-and-forward relaying scheme, the relays collectively build two network beamformers, each of which enables communication between the two transceivers in one pair. To optimally calculate the primary and secondary network parameters, we propose a max-min optimization problem which is amenable to a simple line search based solution with a low computational complexity.