Research On Channel Transmission Characateristics Based On Human Body Communication

Human Body Communication(HBC)is one kind of short-distance wireless communication technology which runs around or inside human body.With the characteristics of good anti-interference performance,extremely low power consumption and safety to human body,HBC plays a increasingly important role in medical and health applications,the handicapped assistance,consumer electronics and user identification.In order to study this wireless communication technology,some scenarios of body communication channel in practical applications are modeled and their transmission characteristics are analyzed.In addition,a contact human communication channel model is proposed to provide theoretical support for body-to-body communication.Lastly,the influence of the transmitter and receiver port structure on the transmission characteristics of HBC is discussed.The domestic and international development course of HBC technology is listed and the advantages and progress of HBC technology in different stages are put into comparison,which gives a clearer view of the process of continuous improvement and development of this technology.Firstly,research on transmission characteristics of channels in single body area network.Combined with the latest research theory and results of human body communication technology,an innovative method to study the signal transmission characteristics of HBC body surface link is proposed.The attenuation characteristics of signal transmission links with correspondingly same transmitter and receiver positions in different human models are compared and analyzed,while the conventional method is to study the signal transmission characteristics of different links only under one model.Finally,based on this method,the signal transmission characteristics of links in single body area network is studied and compared with the conclusions under conventional approach.It is found that this novel method to study the signal transmission characteristics can be regarded as a supplement to the existing research method.A more comprehensive understanding and research about HBC signal transmission characteristics can be reached under the combination of this two approaches.Secondly,modeling and signal transmission characteristic analysis of a contact HBC channel.Based on practical scenarios,a special contact human body communication channel is modeled by shaking hands.There is few discussions on the contact scene between human bodies in the existing researches.Considering that this kind of application scene is typically common,a contact body channel model is constructed via handshake between two bodies.At first,the surface wave transmission theory is introduced to study the transmission characteristics of this kind of channel model and as a result,a contact HBC channel attenuation model is reached.Then,the shadowing effect of this kind of attenuation model is proposed and its statistical distribution characteristics are analyzed.Further,The path loss characteristics of the arm channel in the 200m-1200 mm length range in the HBC frequency band are analyzed.At last,the signal transmission characteristics of arm channels between single body area network and contact body area network environment are put into comparison,and some differences are obtained.Finally,research on the influence of port structure on HBC signal transmission.considering the electrode structure of transmitters and receivers,the HBC channels with different port electrode size,different port impedance and different electrode plate gap are modeled by the method of controlling of variable.The transmission characteristics under those various conditions are analyzed.As a result,some optimal structure parameters of port electrodes are obtained,which can provide a reference for the future human body communication researches.The research method for single body area communication proposed in this paper is a new human communication approach to study HBC.The path loss model of contact scenes can provide some theoretical support for the interaction of wearable devices between bodies and the correlation between electrode structure and path loss can guide the improvement of wearable devices.