Filter-and-forward based full-duplex relay networks with cooperative beamforming

In this paper, we consider full-duplex (FD) relay networks with filter-and-forward (FF) based multiple relays, where relay filters jointly mitigate self-interference (SI), inter-relay interference (IRI), and inter-symbol interference (ISI). We consider the filter design problem based on signal-to-noise-plus-interference ratio maximization subject to a relay transmit power constraint. To make the problem tractable, we propose two methods; the first method imposes an additional constraint that the filter responses to SI and IRI should be zero; the second method makes the i.i.d. assumption on the relay transmit signals. Simulation results show that the proposed FF-FD scheme outperforms a conventional FF-based half-duplex scheme regarding achievable rate. We also consider the filter design based on the second-order statistics of channel coefficients.