The energy consumption of cooperative beamforming was studied under given requirements on the end-to-end bit error rate （BER）

and the optimal numbers of cooperative node were obtained for different propagation environments and transmission distances. Considering both transmit and circuit energies

a practical energy consumption model of co- operative beamforming in WSN was first proposed

and then its closed-form approximate solution was obtained. Based on this model

the energy consumption of cooperative beamforming was minimized by optimizing the numbers of coop- erative nodes. Analysis and simulations show that over some distance ranges

cooperative beamforming can achieve en- ergy savings compared with non-cooperative and STBC-based cooperative systems. Moreover

it is showed that there are the optimal numbers of cooperative nodes to minimize the total energy consumption for different propagation environ- ments and transmission distances.