Distributed Beamforming for Wireless Sensor Networks in 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 sensor network (WSN). 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 beamformers aim to maintain the beamforming response in the desired direction equal to unity. It is shown that the so-obtained beamformers are not suitable for a distributed implementation in WSNs. We hence propose a novel distributed collaborative beamforming (DCB)technique that can be implemented in a distributed fashion and, further, well-approximates both transmit and receive CB techniques. The performance of the proposed DCB is analyzed and its advantages against the conventional DCB, which is designed without taking into account the presence of local scattering in the source or receiver vicinity, are analytically proved and are further verified by simulations.