The Research On The Key Techniques For Visual Prosthesis Energy And Data Wireless Transmission

Visual prosthesis,an effective medical treatment for visual irreversible damage,is widely concerned in the field of bioelectronics.The most important problem to be solved in visual prosthesis and other implantable devices clinical application,is the wireless transmission of energy and data in vivo and in vitro.This paper studies the key technologies of visual prosthesis energy and data wireless transmission system modeling.The main innovative achievement are summarized as follows:1.In order to solve the contradiction between the high efficient energy transmission and the high speed data transmission of the visual prosthesis,this paper,on the basis of MDAPSK(M-ary differentially-encoded amplitude and phase-shift Keying)technology,puts forward the scheme for the first time which has the same carrier frequency and transmits energy and data with one coil group.The scheme only requires a set of coupling coils,which greatly reduces the volume of the embedded cell and greatly reduces the transmission interference caused by multiple sets of coils.Considering the complexity and error rate performance of MDAPSK scheme,16 DAPSK scheme is selected to realize the energy and data transmission with a set of coils and same carrier frequency in the visual prosthesis system.2.In order to reflect the effect of biological tissue on wireless energy transmission efficiency after the visual prosthesis secondary coil is implanted,this paper introduces the concept of biological capacity for the first time.Considering the influence of the inductor parasitic capacitance and the high frequency equivalent resistance on the system,an accurate model of the wireless energy transmission system of the biological channel is established.The experimental results show that the model is more accurate than the traditional model.On this basis,in order to further improve the efficiency of wireless energy transmission,the paper proposes an optimal matching network method.By this method,the energy efficiency of the secondary loop can be approached to the theoretical extreme value under any load condition.3.Based on COMSOL Multiphysics software and Levenberg-Marquardt optimization fitting method,the path loss model of skin,fat and muscle tissue in 10-410 MHz band is established.On this basis,a bit error rate analysis model of biological channel wireless data transmission is established.The comparison between simulation data and measured data shows that the model has high accuracy.4.In order to further reduce the bit error rate of the biological channel data transmission,combining improved soft demodulation and soft decoding,this paper proposes error suppression and error correction scheme for 16 DAPSK modulation.The soft demodulation and soft decoding algorithm are optimized in this paper.Without loss of the bit error rate performance of the system,the paper reduces hardware complexity and system power consumption.Experimental results verify the feasibility of the scheme.The research results show that the energy and data transmission scheme based on 16 DAPSK,with the same carrier frequency wireless transmission scheme and single coil group,can solve the contradiction between the high frequency transmission of energy and the high speed transmission of data.The biological channel wireless energy transmission system model,efficiency optimization scheme,data communication error rate analysis model and error code correction scheme established in this paper lay a theoretical foundation for the design of wireless energy and data transmission system of visual prosthesis.