Research On Simultaneous Wireless Information And Power Transfer System Based On Time Reversal

With the explosive growth of wireless electronic products,the problem of communication rate consumption and energy consumption becomes more prominent.Simultaneous Wireless Information and Power Transfer(SWIPT)technology which can transfer the information and power simultaneously has become a new research hot spot.The trade-off relationship between rate and energy is usually concerned in the current research of SWIPT.How to ensure the simultaneous improvement of energy transmission efficiency and signal transmission efficiency has become an urgent problem to be solved in the research of simultaneous wireless information and power transfer technology.Based on the basic theory and spatial-temporal focusing effect of Time Reversal(TR)technology,this paper proposes corresponding solutions to the above problems.The specific innovations are as follows:(1)According to the spatial-temporal focusing effect of TR technology,this paper proposes a simultaneous wireless information and power transfer system based on time reversal by the spatial-temporal focusing effect of TR technology to deal with the problems of the low transmission efficiency,radiation pollution in wireless power transmission and multipath interference in wireless information transmission.The TR module is introduced in the transmitter of the SWIPT system,and then the transmitted signal is subjected to TR processing.The theory shows that the receiver of SWIPT system has improved performance in both information rate and energy collection.Moreover,the information receiver of the TR system adopts a single tap mode,which will reduce the complexity of the SWIPT information receiver.(2)This paper proposes a Sequential Convex Programming(SCP)algorithm based on diode circuit to obtain the optimal frequency point amplitude to improve energy efficiency,due to the problem of the energy efficiency inaccuracy by the linear energy harvesting model in SWIPT system.Based on the TR-SWIPT system,the theoretical analysis of the energy receiver by the diode circuit model is carried out,and the relationship between the amplitude of the transmission frequency and the output voltage of the direct current is confirmed.In this paper,we have a non-convex optimization problem that changes the amplitude of the frequency to maximize the output voltage of the direct current.Then we use the sequence convex optimization algorithm to transform the non-convex problem to the convex optimization problem and iteratively find the optimal value about the amplitude of the frequency.(3)This paper proposes a performance verification scheme based on TR SWIPT systemdue to the relationship between the TR system performance and multipath numbers.In this paper,the channel information of a specific location and the number of controllable multipaths are obtained by the channel measurement method in frequency domain carried out in the metal box.Then,this paper combines the system module built by Matlab and the channel information to dynamically change the parameters of the transmitted signal,so as to conveniently analyze the performance of SWIPT system based on different algorithms and explore the influencing factors of the performance.