Beamforming Technology Research Based On Limited Feedback In Wireless Sensor Networks

Beamforming technology is used in the directional transmission and reception of signals.By introducing multi-antenna technology,it can effectively improve the energy efficiency and coverage range of wireless communication and has been widely applied to modern communication networks.In wireless sensor networks,cooperative beamforming uses multiple sensor nodes to form a multi-antenna virtual array and implements beamforming through coordinated transmission among nodes.Collaborative beamforming can effectively decrease the node energy consumption and improve the transmission distance,can be well promoted to sensor networks.In this thesis,we will conduct an in-depth study of the beamforming technology in sensor networks.First of all,we give the system model of the thesis,derives a detailed overview of collaborative beamforming from the mathematical theory,discuss several important parameters in the collaborative beampattern,focuses on the synchronization technology in collaborative transmission,introduce several common synchronization methods and analyze the beamforming under the influence of noise.Then,the thesis studies the phase alignment method in cooperative beamforming more deeply.Based on the existing algorithms,a new phase alignment algorithm using two time slots is proposed.The new method makes full use of the feedback information of the receiver and dynamically adjusts the phase perturbation parameters,which greatly increases the phase convergence speed.The article proves the feasibility through theory and verifies the good performance of the algorithm through the simulation analysis.The thesis finally studies the sidelobe control method in cooperative beamforming to reduce the interference of cooperative information to the nearby nodes.The adopted measure is to choose the appropriate sensor nodes in the nodes cluster.On the basis of existing algorithms,a double-loop sector based node selection algorithm is proposed to effectively suppress the overall value of the sidelobe.In order to achieve more effective suppression of the sidelobe values in a particular direction,we also propose a one-bit feedback node selection algorithm for sidelobe control.Through the comparison of experimental simulation,the proposed algorithm has better sidelobe control effect.