Energy efficient collaborative beamforming in wireless sensor networks

Reducing energy consumption is critical for wireless sensor networks. The dominant factor is the energy for data transmission. Collaborative beamforming can save transmission energy by improving the directivity of electromagnetic waves so that the signal at the receiver is stronger. Compared with a single transmitter, collaborative beamforming spreads the long distance transmission energy over multiple transmitters. This balances the battery lifetime on individual nodes because each transmitter can use lower power. However, beamforming depends on proper coordination of phases among the participating sensor nodes. This requires communication among the sensor nodes and consumes energy. This paper investigates whether the transmission energy can be saved by using beamforming based on the number of nodes and the total size of data needed to transmit. We determine the minimum size of data to balance the communication overhead when given the total number of nodes.