阅读说明：本技术 基于人体通信信道传输的建模方法、系统、装置 (Modeling method, system and device based on human body communication channel transmission ) 是由 毛静娜 张志伟 于 2020-04-30 设计创作，主要内容包括：本发明属于人体信道通信领域,具体涉及一种基于人体通信信道传输的建模方法、系统、装置,旨在解决现有人体通信信道传输模型精度较低的问题。本系统方法包括基于获取的人体各组织层的电介质参数,构建人体前向路径模型；基于发射机与接收机接地电极之间的夹角、距离,计算反向耦合电容的修正因子,并结合反向耦合电容其连接两端之间的距离,构建反向耦合电容模型；利用接触阻抗检测电路,对信号电极与人体皮肤之间的接触阻抗进行建模,得到接触阻抗模型；将人体前向路径模型、反向耦合电容模型及接触阻抗模型进行串联,得到人体通信信道传输模型。本发明提高了人体通信信道传输模型的精度。(The invention belongs to the field of human body communication, in particular relates to a modeling method, a modeling system and a modeling device based on human body communication channel transmission, and aims to solve the problem of low precision of an existing human body communication channel transmission model. The method of the system comprises the steps of constructing a human body forward path model based on acquired dielectric parameters of each tissue layer of a human body; calculating a correction factor of a reverse coupling capacitor based on an included angle and a distance between grounding electrodes of a transmitter and a receiver, and constructing a reverse coupling capacitor model by combining the distance between two connecting ends of the reverse coupling capacitor; modeling the contact impedance between the signal electrode and the human skin by using a contact impedance detection circuit to obtain a contact impedance model; and connecting the human body forward path model, the reverse coupling capacitance model and the contact impedance model in series to obtain a human body communication channel transmission model. The invention improves the precision of the human body communication channel transmission model.)

1. A modeling method based on human body communication channel transmission is characterized by comprising the following steps:

step S100, calculating first impedance of the circuit model corresponding to the first set part and the second set part based on the acquired dielectric parameters of each tissue layer of the human body; constructing circuit models according to the first impedance of each set part, connecting the circuit models in series, and taking the circuit models after the connection in series as a human body forward path model; the first impedance comprises a transverse impedance and a longitudinal impedance;

step S200, calculating a correction factor of a reverse coupling capacitor through a preset first method based on an included angle and a distance between a grounding electrode of a transmitter and a grounding electrode of a receiver, and constructing a reverse coupling capacitor model by combining the distance between two connecting ends of the reverse coupling capacitor; the reverse coupling capacitor comprises coupling capacitors between grounding electrodes and between the grounding electrode of the transmitter/receiver and the ground;

step S300, respectively modeling the contact impedance between a transmitter signal electrode and human skin and between a receiver signal electrode and the human skin by using a contact impedance detection circuit to obtain a contact impedance model; the contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit;

and S400, connecting the human body forward path model, the reverse coupling capacitance model and the contact impedance model in series to obtain a human body communication channel transmission model.

2. The modeling method based on human body communication channel transmission according to claim 1, wherein "calculating the first impedance of the circuit model corresponding to the first set portion and the second set portion" in step S100 is performed by:

dividing the first set part and the second set part into a plurality of basic units respectively, and calculating first impedance of each basic unit circuit model;

and respectively connecting the first impedances of the basic unit one-way models of the set positions in parallel to obtain the first impedances of the circuit models corresponding to the first set position and the second set position.

3. The modeling method based on human body communication channel transmission according to claim 2, wherein the calculation method of the longitudinal impedance of the first impedance of each basic unit circuit model is:

wherein, Y_lRepresents the longitudinal impedance, Y_iRepresenting the longitudinal impedance of the tissue of layer i, G_i、B_iRespectively represents the conductance and susceptance of the ith layer tissue, i is a natural number and represents a subscript, and j represents an imaginary number.

4. The modeling method based on human body communication channel transmission according to claim 3, wherein the calculation method of the lateral impedance of the first impedance of each basic unit circuit model is:

wherein Z is_tRepresents the lateral impedance, Z_iRepresents the transverse impedance of the i-th layer of tissue, R_i、C_iRespectively representing the resistance and capacitance of the i-th layer tissue, S_iIs the cross-sectional area of the tissue of the ith layer, σ'_iRepresents the real part of the electrical conductivity of the tissue layer of the ith layer,₀denotes a dielectric constant in vacuum'_riDenotes the real part of the relative permittivity of the tissue layer of the i-th layer and ω denotes the angular frequency.

5. The modeling method based on human body communication channel transmission according to claim 1, wherein "calculating the correction factor of the reverse coupling capacitance by a preset first method" in step S200 is performed by:

where θ represents the angle between the transmitter and receiver ground electrodes, D_TRRepresents the distance between the ground electrodes, M (θ) represents a correction factor for the coupling capacitance between the ground electrodes, and N (θ) represents a correction factor for the coupling capacitance between the transmitter/receiver ground electrode and ground.

6. The modeling method based on human body communication channel transmission according to claim 5, wherein the reverse coupling capacitance model is:

wherein K is a preset correction factor,₀which represents the dielectric constant in a vacuum,_rdenotes the relative permittivity, S denotes the area of the ground electrode, l denotes the side length of the ground electrode, D_GNDRepresenting the distance between the transmitter/receiver and ground, Ccross representing the coupling capacitance between the ground electrodes, C_GNDRepresenting the coupling capacitance between the transmitter/receiver ground electrode and ground.

7. The modeling method based on human body communication channel transmission according to claim 1, wherein in step S300, "modeling the contact impedance between the transmitter signal electrode and the human body skin, and between the receiver signal electrode and the human body skin respectively" is performed by:

in the capacitance detection circuit, a peak detection circuit and an analog-to-digital conversion circuit ADC are used for obtaining capacitive impedance values between each signal electrode and the skin for modeling;

in the resistance detection circuit, based on the detected voltage value, the resistance value between each signal electrode and the skin is acquired through an analog-to-digital conversion circuit and modeled.

8. A modeling system based on human body communication channel transmission is characterized by comprising a human body forward path modeling module, a reverse coupling capacitance modeling module, a contact impedance modeling module and a communication channel transmission modeling module;

the human body forward path modeling module is configured to calculate first impedance of the circuit model corresponding to the first set part and the second set part based on the acquired dielectric parameters of each tissue layer of the human body; constructing circuit models according to the first impedance of each set part, connecting the circuit models in series, and taking the circuit models after the connection in series as a human body forward path model; the first impedance comprises a transverse impedance and a longitudinal impedance;

the reverse coupling capacitance modeling module is configured to calculate a correction factor of a reverse coupling capacitance through a preset first method based on an included angle and a distance between a grounding electrode of a transmitter and a grounding electrode of a receiver, and construct a reverse coupling capacitance model by combining the distance between two connecting ends of the reverse coupling capacitance; the reverse coupling capacitor comprises coupling capacitors between grounding electrodes and between the grounding electrode of the transmitter/receiver and the ground;

the contact impedance modeling module is configured to utilize a contact impedance detection circuit to respectively model contact impedances between a transmitter signal electrode and human skin and between a receiver signal electrode and the human skin to obtain a contact impedance model; the contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit;

the communication channel transmission modeling module is configured to connect the human body forward path model, the reverse coupling capacitance model and the contact impedance model in series to obtain a human body communication channel transmission model.

9. A storage device having stored therein a plurality of programs, wherein the program applications are loaded and executed by a processor to implement the modeling method based on human body communication channel transmission of any one of claims 1 to 7.

10. A processing arrangement comprising a processor, a storage device; a processor adapted to execute various programs; a storage device adapted to store a plurality of programs; characterized in that said program is adapted to be loaded and executed by a processor to implement the modeling method based on human body communication channel transmission of any one of claims 1 to 7.

Technical Field

The invention belongs to the field of human body communication, and particularly relates to a modeling method, a modeling system and a modeling device based on human body communication channel transmission.

Background

The human body channel communication technology is a communication mode using a human body as a transmission medium, and compared with a traditional wireless communication mode, the human body channel communication has the following advantages: 1) the communication channel is a human body, the conductivity of the human body is higher than that of air, and therefore the path loss is low; 2) the signal is transmitted by using a human body, so that the monitoring and the interference are difficult, and the safety is strong; 3) the electrode is adopted for human body channel communication to replace a large-size antenna, so that the size is small, and the advantage of miniaturization is achieved; 4) its power consumption is relatively low due to its low path loss and the need to drive a low impedance antenna.

The human body channel communication principle is that signal electrodes of a transmitter and a receiver are attached to a human body, the human body forms a forward path, and two suspended ground electrodes form a reverse path through coupling with the ground and coupling between the two ground electrodes.

In order to avoid complicated tests on the human body and better understand the transmission characteristics of the human body channel, a high-precision human body channel transmission model needs to be established. The existing human body channel transmission model mainly comprises a Zimmerman model, an RC circuit model, a finite element model, a transmission line model, a field model and a cascade network model. These human body channel transmission models do not take the physiological characteristics of the human body, the dielectric characteristics of tissue layers, the reverse coupling path formed by ground electrodes, and the influence of contact impedance between signal electrodes and the skin into comprehensive consideration, so that the accuracy of the model is not high enough. Meanwhile, the existing model does not consider individual differences, so that the precision of the model has larger difference on different individuals. Therefore, it is necessary to comprehensively analyze the transmission mechanism of body channel communication, and comprehensively consider all possible influencing factors to establish a more accurate transmission model suitable for different individual body channels.

Disclosure of Invention

In order to solve the above problems in the prior art, that is, to solve the problem that the accuracy of the existing human body communication channel transmission model is low due to the fact that the physiological characteristics of the human body, the dielectric characteristics of tissue layers, the reverse coupling path formed by ground electrodes and the influence of contact impedance between signal electrodes and the skin are not comprehensively considered, in a first aspect of the present invention, a modeling method based on human body communication channel transmission is provided, the method includes:

step S100, calculating first impedance of the circuit model corresponding to the first set part and the second set part based on the acquired dielectric parameters of each tissue layer of the human body; constructing circuit models according to the first impedance of each set part, connecting the circuit models in series, and taking the circuit models after the connection in series as a human body forward path model; the first impedance comprises a transverse impedance and a longitudinal impedance;

step S200, calculating a correction factor of a reverse coupling capacitor through a preset first method based on an included angle and a distance between a grounding electrode of a transmitter and a grounding electrode of a receiver, and constructing a reverse coupling capacitor model by combining the distance between two connecting ends of the reverse coupling capacitor; the reverse coupling capacitor comprises coupling capacitors between grounding electrodes and between the grounding electrode of the transmitter/receiver and the ground;

step S300, respectively modeling the contact impedance between a transmitter signal electrode and human skin and between a receiver signal electrode and the human skin by using a contact impedance detection circuit to obtain a contact impedance model; the contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit;

and S400, connecting the human body forward path model, the reverse coupling capacitance model and the contact impedance model in series to obtain a human body communication channel transmission model.

In some preferred embodiments, the step S100 of "calculating the first impedance of the circuit model corresponding to the first setting position and the second setting position" includes:

dividing the first set part and the second set part into a plurality of basic units respectively, and calculating first impedance of each basic unit circuit model;

and respectively connecting the first impedances of the basic unit one-way models of the set positions in parallel to obtain the first impedances of the circuit models corresponding to the first set position and the second set position.

In some preferred embodiments, the method for calculating the longitudinal impedance of the first impedance of each basic unit circuit model includes:

wherein Y represents the longitudinal impedance, Y_iRepresenting the longitudinal impedance of the tissue of layer i, G_i、B_iRespectively represents the conductance and susceptance of the ith layer tissue, i is a natural number and represents a subscript, and j represents an imaginary number.

In some preferred embodiments, the method for calculating the lateral impedance of the first impedance of each basic unit circuit model includes:

wherein Z is_tRepresents the lateral impedance, Z_iRepresents the transverse impedance of the i-th layer of tissue, R_i、C_iRespectively representing the resistance and capacitance of the i-th layer tissue, S_iIs the cross-sectional area of the tissue of the ith layer, σ'_iRepresents the real part of the electrical conductivity of the tissue layer of the ith layer,₀denotes a dielectric constant in vacuum'_riDenotes the real part of the relative permittivity of the tissue layer of the i-th layer and ω denotes the angular frequency.

In some preferred embodiments, in step S200, "calculating the correction factor of the reverse coupling capacitance by a preset first method" includes:

where θ represents the angle between the transmitter and receiver ground electrodes, D_TRRepresents the distance between the ground electrodes, M (θ) represents a correction factor for the coupling capacitance between the ground electrodes, and N (θ) represents a correction factor for the coupling capacitance between the transmitter/receiver ground electrode and ground.

In some preferred embodiments, the reverse coupling capacitance model is:

wherein K is a preset correction factor,₀which represents the dielectric constant in a vacuum,_rdenotes the relative permittivity, S denotes the area of the ground electrode, l denotes the side length of the ground electrode, D_GNDRepresenting the distance between the transmitter/receiver and ground, Ccross representing the coupling capacitance between the ground electrodes, C_GNDRepresenting the coupling capacitance between the transmitter/receiver ground electrode and ground.

In some preferred embodiments, in step S300, "modeling the contact impedance between the transmitter signal electrode and the human skin and between the receiver signal electrode and the human skin respectively" is performed by:

in the capacitance detection circuit, a peak detection circuit and an analog-to-digital conversion circuit ADC are used for obtaining capacitive impedance values between each signal electrode and the skin for modeling;

in the resistance detection circuit, based on the detected voltage value, the resistance value between each signal electrode and the skin is acquired through an analog-to-digital conversion circuit and modeled.

In a second aspect of the present invention, a modeling system based on human body communication channel transmission is provided, the system includes a human body forward path modeling module, a reverse coupling capacitance modeling module, a contact impedance modeling module, and a communication channel transmission modeling module;

the human body forward path modeling module is configured to calculate first impedance of the circuit model corresponding to the first set part and the second set part based on the acquired dielectric parameters of each tissue layer of the human body; constructing circuit models according to the first impedance of each set part, connecting the circuit models in series, and taking the circuit models after the connection in series as a human body forward path model; the first impedance comprises a transverse impedance and a longitudinal impedance;

the reverse coupling capacitance modeling module is configured to calculate a correction factor of a reverse coupling capacitance through a preset first method based on an included angle and a distance between a grounding electrode of a transmitter and a grounding electrode of a receiver, and construct a reverse coupling capacitance model by combining the distance between two connecting ends of the reverse coupling capacitance; the reverse coupling capacitor comprises coupling capacitors between grounding electrodes and between the grounding electrode of the transmitter/receiver and the ground;

the contact impedance modeling module is configured to utilize a contact impedance detection circuit to respectively model contact impedances between a transmitter signal electrode and human skin and between a receiver signal electrode and the human skin to obtain a contact impedance model; the contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit;

the communication channel transmission modeling module is configured to connect the human body forward path model, the reverse coupling capacitance model and the contact impedance model in series to obtain a human body communication channel transmission model.

In a third aspect of the present invention, a storage device is provided, in which a plurality of programs are stored, the programs applying the modeling method based on human body communication channel transmission loaded and executed by a processor.

In a fourth aspect of the invention, a processing arrangement is provided, comprising a processor, a storage device; a processor adapted to execute various programs; a storage device adapted to store a plurality of programs; the program is adapted to be loaded by a processor and to perform the above-described modeling method based on human body communication channel transmission.

The invention has the beneficial effects that:

the invention improves the precision of the human body communication channel transmission model. According to the invention, dielectric parameters of each tissue layer of different individuals are obtained according to physiological characteristics and tissue layer dielectric characteristics of a human body, the transverse impedance and the longitudinal impedance of each set part of the human body model are calculated, a circuit model is constructed, and the constructed circuit models are connected in series to obtain a human body forward path model. Then, a correction factor of the reverse coupling capacitance is obtained through an included angle and a distance between the grounding electrodes of the transmitter and the receiver, and a reverse coupling capacitance model is constructed by combining the distance between the grounding electrodes (or the grounding electrodes and the ground). The problem that the fringing field is ignored in the traditional coupling capacitance model is solved.

And finally, respectively modeling the contact impedance between the signal electrode of the transmitter and the skin of the human body and between the signal electrode of the receiver and the skin of the human body by using a contact impedance detection circuit to obtain a contact impedance model. And integrating the models corresponding to the human body forward path, the capacitive coupling reverse path and the contact impedance between the signal electrode and the skin to obtain a human body communication channel transmission model. The model is closer to the transmission mechanism of human body channel communication, thereby improving the precision of the model and being suitable for different individuals.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings.

FIG. 1 is a flow chart diagram of a modeling method based on human body communication channel transmission according to an embodiment of the invention;

FIG. 2 is an exemplary diagram of an equivalent circuit model of a human arm in accordance with one embodiment of the present invention;

FIG. 3 is a block diagram of a modeling system based on human body communication channel transmission according to an embodiment of the present invention;

FIG. 4 is a schematic circuit diagram of a human body channel communication transmission model according to an embodiment of the present invention;

fig. 5 is a schematic circuit diagram of a contact impedance detection circuit according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the related invention are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The modeling method based on human body communication channel transmission of the invention, as shown in figure 1, comprises the following steps:

step S100, calculating first impedance of the circuit model corresponding to the first set part and the second set part based on the acquired dielectric parameters of each tissue layer of the human body; constructing circuit models according to the first impedance of each set part, connecting the circuit models in series, and taking the circuit models after the connection in series as a human body forward path model; the first impedance comprises a transverse impedance and a longitudinal impedance;

step S200, calculating a correction factor of a reverse coupling capacitor through a preset first method based on an included angle and a distance between a grounding electrode of a transmitter and a grounding electrode of a receiver, and constructing a reverse coupling capacitor model by combining the distance between two connecting ends of the reverse coupling capacitor; the reverse coupling capacitor comprises coupling capacitors between grounding electrodes and between the grounding electrode of the transmitter/receiver and the ground;

step S300, respectively modeling the contact impedance between a transmitter signal electrode and human skin and between a receiver signal electrode and the human skin by using a contact impedance detection circuit to obtain a contact impedance model; the contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit;

and S400, connecting the human body forward path model, the reverse coupling capacitance model and the contact impedance model in series to obtain a human body communication channel transmission model.

In order to more clearly explain the modeling method based on human body communication channel transmission of the present invention, the following will describe each step in an embodiment of the method of the present invention in detail with reference to the accompanying drawings.

Step S100, calculating first impedance of the circuit model corresponding to the first set part and the second set part based on the acquired dielectric parameters of each tissue layer of the human body; constructing circuit models according to the first impedance of each set part, connecting the circuit models in series, and taking the circuit models after the connection in series as a human body forward path model; the first impedance comprises transverse impedance and longitudinal impedance.

Since the human body has complex physiological characteristics, the physiological characteristics of the human body need to be taken into consideration in the model in order to make the model more accurate. In the present embodiment, the human body may be divided into two parts of an arm and a trunk (including legs) according to the shape of the human body. Wherein the arm is composed of 5 tissue layers, which are respectively: skin layer, fat layer, muscle layer, dense bone layer and bone marrow layer, as shown in FIG. 2, wherein Z_{t_1}，Z_{t_2}……Z_{t_5}Representing the lateral impedance of the layers and G, B representing conductance and susceptance. Since the trunk part includes viscera (such as spleen, liver, etc.), the tissue layers thereof are different from the arms in structure, and the average values of the electrical conductivity and the relative permittivity of the viscera are close to those of the heart, so that the heart layer can be used instead of the internal heart layer, and the tissue layers of the trunk (including legs) are divided into four parts, namely, a skin layer, a fat layer, a muscle layer and a heart layer.

The dielectric parameters of each tissue layer can be obtained according to the biological tissue parameter models of Debye and Cole-Cole, as shown in the formulas (1) and (2):

wherein the content of the first and second substances,and σ^*For the relative dielectric constant and conductivity of each tissue layerElectric power'_r、″_rAre respectively asThe real part and the imaginary part of (a) and (a) are respectively a^*The real and imaginary parts of (a) and (b),₀is the dielectric constant in a vacuum, and,_∞is the dielectric constant, Delta, at infinite frequency_kIs Deybe scattering error, τ_kIs the Debye relaxation time, k is a natural number, representing a subscript, the magnitudes of these parameters are all available from the literature, ω represents the angular frequency, σ represents the static ionic conductivity, and j represents an imaginary number.

Calculating first impedance (transverse impedance and longitudinal impedance) of the circuit model corresponding to the first set position and the second set position based on the dielectric parameters of each tissue layer, and the specific process is as follows:

based on the RC circuit model and the physiological characteristics of the human body and the characteristics of the tissue layer dielectric parameter frequency, the arm portion of the human body is first divided into a cascade of N basic cell circuits, each of which is composed of a transverse impedance and a longitudinal impedance, as shown in fig. 2. The lateral impedance of each tissue layer may be equivalent to a parallel connection of conductance G and susceptance B, i.e.: y ═ G + jB. The longitudinal impedance of each elementary cell circuit can thus be obtained from the parallel connection of the longitudinal impedance values of the five tissue layers, which is calculated as shown in equations (3) (4) (5) (6):

G_i＝K_iσ′_i(ω) (4)

B_i＝K_iω′_ri(ω)₀(5)

wherein, Y_lRepresents the longitudinal impedance, Y_iRepresenting the longitudinal impedance of the tissue of layer i, G_i、B_iRespectively represents the conductance and susceptance of the ith layer tissue, i is a natural number and representsThe symbol, ω, denotes angular frequency, t_jDenotes the thickness of the j-th tissue layer'_riIs the real part of the relative permittivity, σ ', of the tissue layer of the i-th layer'_iIs the real part of the electrical conductivity of the tissue layer of the i-th layer, K_iIs a parameter of the i-th tissue layer, L is the lateral distance of the basic unit, and can be based on the forward transmission distance D_fThe N is obtained by dividing the number N of the basic unit partitions, a balance needs to be made on the calculation efficiency and the calculation precision of the model, and the model can be efficiently calculated and simultaneously achieve higher precision when the simulation finds that the N is 150.

Also, the lateral impedance Z of the basic cell_tThe transverse impedance through the five tissue layers is obtained in parallel, as shown in the formulas (7) and (8):

wherein Z is_tRepresents the lateral impedance, Z_iRepresents the transverse impedance of the i-th layer of tissue, R_i、C_iRespectively representing the resistance and capacitance of the i-th layer tissue, S_iIs the cross-sectional area of the tissue of the ith layer.

The modeling of the torso portion is similar to the modeling of the arms, except that the torso portion is used as a whole for simplicity in modeling, and no basic units are divided.

According to the human body structure, the circuit of the arm part of the human body and the circuit of the trunk (including the legs) part of the human body are connected in series to form a forward path model of the human body. Tissue layer thickness factors in the model reflect that the model is applicable to different individuals, and the influence of individual differences on the channel transmission characteristics is taken into consideration. The model contains dielectric parameters of each tissue layer, and the influence of the human skin state on the transmission channel characteristics is mainly reflected in the dielectric parameters under different skin states, so the model is still suitable for different skin states of the human body.

Step S200, calculating a correction factor of a reverse coupling capacitor through a preset first method based on an included angle and a distance between a grounding electrode of a transmitter and a grounding electrode of a receiver, and constructing a reverse coupling capacitor model by combining the distance between two connecting ends of the reverse coupling capacitor; the reverse coupling capacitance includes the coupling capacitance between the ground electrodes, between the ground electrode of the transmitter/receiver and the ground.

The coupling capacitance in the reverse path is another major factor affecting the transmission characteristics of the human body channel. According to the transmission-mechanism of human body channel communication, there are mainly two reverse coupling capacitance values: coupling capacitance C between transmitter GND electrode and receiver GND electrode_crossAnd coupling capacitance C between the transmission/receiver GND electrode and the ground_GND,TX/C_GND,RX. The two reverse coupling capacitance values vary with the parameters of the GND electrodes, such as the distance between the GND electrodes, the distance between the GND electrodes and the ground, the size of the GND electrodes, and the like. Therefore, it is necessary to establish a calculation formula of the reverse coupling capacitance, and it is known that the conventional parallel plate capacitance C is calculated as shown in formula (9):

wherein the content of the first and second substances,_ris the relative dielectric constant, S is the area of the plate, d_plIs the distance between the two parallel plates.

Formula (9) only applies to d_pl＜S^0.5In this case the charge density on the parallel plate can be considered uniform, its fringing field effect being negligible. However, for two coupling capacitances in human body channel communication, the distance between the GND electrodes and the height of the GND electrode to the ground are much larger than the size of the GND electrodes. At the moment, the fringe field cannot be ignored, and the existence of the human body can also bring influence to the coupling capacitance. The traditional parallel plate capacitance calculation formula is not suitable for C_crossAnd C_GND,TX/C_GND,RXAnd (4) calculating. Therefore, in the embodiment, the reverse coupling electricity in the human body channel communication is established by using the finite element simulation methodAnd (4) containing a model. The method comprises the following specific steps:

establishing a human body model in electromagnetic simulation software, comprising the following steps: the arms, legs, abdomen and thorax are four parts, each part comprising a tissue layer. After the construction, the dielectric constant and conductivity of each tissue layer of the human body are introduced, the thickness of each tissue layer of different human bodies is measured, and the measured thickness values are introduced into the model. I.e. modeling a human model.

Two copper sheets are constructed in simulation software as grounding electrodes, and are preferably arranged 0.5cm above the human body model in the embodiment, and the distance between the two copper sheets is used as a reverse path distance in human body channel communication.

And simulating coupling capacitance values between the ground electrodes corresponding to different inter-electrode distances, and fitting according to simulation data to obtain a calculation model of the reverse coupling capacitance and the reverse path distance between the two ground electrodes.

Simulating reverse coupling capacitance values corresponding to the distances between different electrodes and the ground, and fitting according to simulation data to obtain a calculation model of the reverse coupling capacitance between the ground electrode and the ground and the distance between the ground electrode and the ground; and correcting the calculation model of the reverse coupling capacitance according to the influence of the ground electrodes with different shapes and sizes on the reverse coupling capacitance.

Wherein Ccross, C_GNDThe correction factor of (2) is calculated as shown in equations (10) (11):

where θ represents the angle between the transmitter and receiver ground electrodes, D_TRRepresents the distance between the ground electrodes, M (theta) represents the correction factor of Cacross, and N (theta) represents C_GNDThe correction factor of (1).

And (3) constructing a reverse coupling capacitance model by combining the distance between two ends of the connection of the reverse coupling capacitance based on the correction factor, as shown in the formulas (12) and (13):

wherein K is a preset correction factor, S represents the area of the grounding electrode, l represents the side length of the grounding electrode, and D_GNDRepresenting the distance between the transmitter/receiver and the earth.

Step S400, respectively modeling the contact impedance between a transmitter signal electrode and human skin and between a receiver signal electrode and the human skin by using a contact impedance detection circuit to obtain a contact impedance model; the contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit.

In the present embodiment, the contact impedance between the signal electrode and the skin is modeled using a contact impedance detection circuit, as shown in fig. 5. The contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit, namely, a capacitive impedance value when the electrode is contacted with a human body is detected through the capacitance detection circuit, and a resistance value when the electrode is contacted with the human body is detected through the resistance detection circuit. The specific working processes of the capacitance detection circuit and the resistance detection circuit are as follows:

in the capacitance impedance detection circuit, an injection source is a voltage source of 1.25MHz, and the resonance frequency of a constructed LC network is influenced by the capacitance between an electrode and a human body. If the capacitive impedance between the electrode and the human body increases, the resonance frequency will decrease and the voltage value detected by the peak collecting detector will decrease, and vice versa. The ADC can determine the value of the capacitive impedance between the electrode and the skin from the peak detection circuit and the analog-to-digital conversion circuit.

The main principle of resistance detection is to inject a current source into a human body, then detect a voltage value, and finally convert the voltage value into a digital value for output by an analog-to-digital conversion circuit ADC, thereby determining the resistance value between an electrode and the skin.

And S500, connecting the human body forward path model, the reverse coupling capacitance model and the contact impedance model in series to obtain a human body communication channel transmission model.

In this embodiment, a human body communication channel transmission model is constructed by integrating a human body forward path model, a reverse coupling capacitance model, and a contact impedance model. The models constructed by the human body forward path, the reverse coupling capacitor and the contact impedance are connected in series to obtain a human body communication channel transmission model, and the constructed model is shown in fig. 4, wherein C_{leak_arm}And C_{leak_torso}Is a constant, representing the coupling capacitances between the arms and torso and ground, 0.7pF and 15pF, Z respectively_txAnd Z_rxRespectively representing the contact impedance between the transmitter signal electrode and the skin, the contact impedance between the receiver signal electrode and the skin, R_RXRepresenting the input impedance of the receiver, Vin and Vout representing the transmit voltage of the transmitter and the receive voltage of the receiver, respectively, Z_waAnd Y_laRespectively representing the transverse and longitudinal impedance of the arm, Z_wtAnd Y_ltRepresenting the transverse and longitudinal impedance of the torso, respectively.

A modeling system based on human body communication channel transmission according to a second embodiment of the present invention, as shown in fig. 3, includes: the human body forward path modeling module 100, the reverse coupling capacitance modeling module 200, the contact impedance modeling module 300 and the communication channel transmission modeling module 400;

the human body forward path modeling module 100 is configured to calculate first impedances of the circuit models corresponding to the first set part and the second set part based on the acquired dielectric parameters of each tissue layer of the human body; constructing circuit models according to the first impedance of each set part, connecting the circuit models in series, and taking the circuit models after the connection in series as a human body forward path model; the first impedance comprises a transverse impedance and a longitudinal impedance;

the reverse coupling capacitance modeling module 200 is configured to calculate a correction factor of a reverse coupling capacitance by a preset first method based on an included angle and a distance between a ground electrode of a transmitter and a ground electrode of a receiver, and construct a reverse coupling capacitance model by combining the distance between two connecting ends of the reverse coupling capacitance; the reverse coupling capacitor comprises coupling capacitors between grounding electrodes and between the grounding electrode of the transmitter/receiver and the ground;

the contact impedance modeling module 300 is configured to utilize a contact impedance detection circuit to respectively model contact impedances between a transmitter signal electrode and human skin and between a receiver signal electrode and human skin to obtain a contact impedance model; the contact impedance detection circuit comprises a capacitance detection circuit and a resistance detection circuit;

the communication channel transmission modeling module 400 is configured to connect the human forward path model, the reverse coupling capacitance model, and the contact impedance model in series to obtain a human communication channel transmission model.

It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process and related description of the system described above may refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

It should be noted that, the modeling system based on human body communication channel transmission provided in the foregoing embodiment is only illustrated by the division of the above functional modules, and in practical applications, the above functions may be allocated to different functional modules according to needs, that is, the modules or steps in the embodiments of the present invention are further decomposed or combined, for example, the modules in the foregoing embodiment may be combined into one module, or may be further split into multiple sub-modules, so as to complete all or part of the above described functions. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps, and are not to be construed as unduly limiting the present invention.

A storage device of a third embodiment of the present invention stores therein a plurality of programs adapted to be loaded by a processor and to implement the above-described modeling method based on human body communication channel transmission.

A processing apparatus according to a fourth embodiment of the present invention includes a processor, a storage device; a processor adapted to execute various programs; a storage device adapted to store a plurality of programs; the program is adapted to be loaded and executed by a processor to implement the above-described modeling method based on human body communication channel transmission.

It is clear to those skilled in the art that, for convenience and brevity, the specific working processes and descriptions of the storage device and the processing device described above may refer to the corresponding processes in the example of the signing method, and are not described herein again.

Those of skill in the art would appreciate that the various illustrative modules, method steps, and modules described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that programs corresponding to the software modules, method steps may be located in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. To clearly illustrate this interchangeability of electronic hardware and software, various illustrative components and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as electronic hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing or implying a particular order or sequence.

The terms "comprises," "comprising," or any other similar term are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.