Distributed blind adaptive computation of beamforming weights for relay networks

In the present paper, we propose two novel algorithms which enable the relay cooperation for the distributed computation of the beamforming weights in a blind and adaptive manner, without the need to forward the data to a fusion center. In the first scheme, the beamforming vector is computed through minimization of the total transmit power subject to a receiver quality-of-service constraint (QoS). In the second scheme, the beamforming weights are obtained through maximization of the receiver signal-to-noise-ratio (SNR) subject to a total transmit power constraint. The proposed approaches distribute the computational overhead equally among the relay nodes and achieve close performance to the one of the optimal beamforming solutions. Note, that the aforementioned optimal solutions are derived assuming perfect channel state information at the relays' side. In order to verify the performance of the proposed approaches, indicative simulations were carried out for static and time-varying channels.