Distributed collaborative beamforming with minimum overhead for local scattering environments

In this paper, transmit and receive collaborative beamforming (CB) techniques are considered to achieve a dualhop communication from a source to a receiver, through a wireless network comprised of K independent terminals. Whereas the previous works assumed a model of plane wavefronts, here, a local scattering in the source or receiver vicinity is considered, thereby broadening the range of applications in real-world environments. Taking into account the local scattering, these CB techniques aim to maintain the beamforming response in the desired direction equal to unity. It is shown that the so-obtained collaborative beamformers are not suitable for a distributed implementation. We hence propose a novel beamformer solution that can be implemented in a distributed fashion and, further, well-approximates both transmit and receive collaborative beam-formers. The performance of the proposed distributed CB (DCB) technique is analyzed and its advantages against the conventional DCB technique, which is designed without taking into account the presence of local scattering in the source or receiver vicinity, are analytically proved and further verified by simulations.