A Human Body Channel Modeling Method for Wearable Devices Based on Multilayer Transmission Line Model

Abstract

The invention relates to a wearable equipment human channel modelling method based on a multilayer transmission line model. The modelling method comprises the following steps: firstly, constructing a hierarchical geometric model of a human or a human tissue part; secondarily, dividing the human or the human tissue part impedance into an axial transmission impedance and a cyclic transmission impedance in each layer of tissue, and an interlayer radial transmission impedance between different tissues according to a distribution condition of the current density in the human or the human tissue part; and then equalizing the axial transmission of each layer of tissue as a parallel transmission line, and establishing a multi-layer transmission line circuit model to acquire a mathematical model of the multilayer transmission line; finally, computing the axial distribution impedance and the cyclic distribution impedance of each layer of impedance and the interlayer radial distribution impedance, solving a multilayer transmission line mathematical equation to acquire a voltage expression formula and a current expression formula of the multilayer transmission line, thereby acquiring a channel character of the human or the human tissue part. By sufficiently considering the influence on the signal transmission feature by the multi-layer human tissue, the real condition of the really measurement environment can be comprehensively reflected, and the coincidence with the channel character of the real human is higher.

Description

technical field [0001] The invention relates to a human body channel modeling method of a wearable device based on a multilayer transmission line model. Background technique [0002] The patent (application number 200910081416.X) proposes a finite element human body modeling method for human body communication. The various parts of the human body are geometrically abstracted according to the shape characteristics, the internal geometric structure of each part of the human body is defined, the electromagnetic characteristic parameters of the dielectric layer of each part of the human body are set, and the complete finite element human body model is formed by connecting various parts of the human body. The patent (application number 201410281066.2) proposes a method and system for modeling human communication channels based on heterogeneous media. The human body is divided into multiple structural models according to the structure, and the structural models are abstracted int...

AI Technical Summary

Problems solved by technology

The existing human body channel modeling is mainly based on circuit models and finite element models, but these models mostly focus on the research of low-frequency human body channel characteristics (generally less than 10MHz). When the signal frequency rises to a certain value, the electromagnetic field propagation effect cannot be ignored. , the signal will be transmitted in the form of electromagnetic waves, the circuit model established by lumped parameters and the finite element model established by quasi-electrostatic field are no longer suitable for the analysis of human body channel characteristics

In addition, in the study of the characteristics of current-coupled human body communication channels, there is a problem that has not been well resolved in the existing circuit models and finite element models: the model calculation or simulation results are quite different from the actual environmental experimental measurement results

The human channel is different from a single metal conductor. It contains multiple layers of biological tissue, and the electromagnetic properties of each layer of biological tissue are also different. The current is not only distributed in a single tissue, but diffused in all biological tissues. Therefore, it cannot be simply Applying Existing Generic Transmission Line Model Theory to Human Body Channel Modeling

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