Collaborative transmit beamforming

Collaborative transmit beamforming is a form of communication where multiple transmitters cooperate to send a common message. If each transmitter properly controls the phase of its signal, the signals interfere constructively at the destination, translating in increased range, rate and energy efficiency. Collaborative beamforming has the potential to improve security and interference reduction by attenuating the signal transmitted in unintended directions. There are several challenges in collaborative transmit beamforming, like frequency synchronization, information sharing between nodes, and beampattern performance. This review focuses on the performance of collaborating nodes in terms of beampattern statistics when the transmitters are realized as a distributed ad hoc sensor network, and the nodes are randomly distributed over an area (Ochiai 2005, Mudumbai 2007). We review the design parameters necessary for the network to act as a distributed beamformer and support the finding of (Ochiai 2005) by simulations. The simulations treat the transmitting nodes as a virtual antenna array and collect relevant beampattern statistics.