Multiple peer-to-peer communications for two-way relay networks

In this paper we address the problem of two-way communication in multiple peer-to-peer relay networks, with perfectly known channel state information. Herein, multiple terminal transceiver nodes in the network are organized into two groups, and transceivers in each group want to simultaneously conduct bidirectional communications with their respective peers in the other group through the assistance of multiple relay nodes. Considering a two-time-phase two-way relaying scheme, each relay weights the received signal by a complex number and forwards it. To calculate the relay weighting coefficients, an optimization problem is formulated, in which constraints on received SINRs are imposed and total relay transmit power is minimized subject to these constraints. It is shown that this problem can be relaxed to a semidefinite programming (SDP) which is convex, hence efficient algorithm can be used to solve this optimization problem. Simulation results show the performance of the proposed method in different scenarios, such as different numbers of communication pairs, different numbers of relays, and one-way versus two-way transmission.