Joint Beamforming And Artificial Noise Design Based On SWIPT System

With the rapidly development of science and technology,low-power mobile communication devices can be seen everywhere,which makes us in a high demand for convenient charging.Traditional power transmission is through wire,and there is a great limitation on the charging environment.It is difficult to charge in medical implantation environment.Therefore,the wireless charging technology is widely used in smart home area,medical equipment area and many other areas.The wireless communication system which uses RF signal as a medium can transmit information and energy simultaneously.We call it as simultaneous wireless information and power transfer system(SWIPT)system.Due to the serious power dissipation of free space and low efficiency of energy conversion circuit for energy receiver,the base station must have a larger transmission power in order to meet the basic needs of energy receiver.In this paper,two efficient solutions are proposed to solve the problem of low energy collection and high power demand for base station.First,aiming at the problem of irrational use of interference between users,this paper proposes a joint beamforming design based on SWIPT system,it extends the single beamforming vector to two independent beamforming vectors for the independent control of information and energy.On one hand,this design can realize the directional transmission of information.On the other hand,it can expand the source of energy.In this paper,joint beamforming design based on MISO broadcast system is analyzed and simulated,and then we compared it with the conventional beamforming and zero-forcing beamforming.Simulation results show that the proposed method can effectively reduce the transmission power in the same amount of energy collection by collecting interference as a source of energy.Secondly,aiming at the problem of low energy collection for energy receivers,this paper proposes an artificial noise design based on maximum energy collection.Under this design,the information transmitted by the base station contains both information beam and artificial noise.On one hand,artificial noise can serve as a source of energy,so as to increase the energy collection.On the other hand,it also can interfere with potential eavesdropping users,so as to realize secure transmission of information.In this paper,the theory and Simulation of artificial noise design in MISO broadcast system are analyzed and we compare it with no artificial noise aided design.Simulation results show that the proposed method can increase the energy collection of energy receiver and realize secure transmission of information.In summary,the article deeply studies the following two kinds of methods which can effectively improve energy collection were carried out,respectively joint beamforming design and artificial noise design based on maximum energy collection.In the process of the research,we have achieved some valuable results,meanwhile,the two proposed methods broadened the research direction of SWIPT technology.