Yueming Gao

Modeling for intra-body communication with bone effect

Intra-body communication (IBC) is a new, different “wireless” communication technique based on the human tissue. This short range “wireless” communication technology provides an alternative solution to wearable sensors, home health system, telemedicine and implanted devices. The development of the IBC enables the possibilities of providing less complexity and convenient communication methodologies for these devices. By regarding human tissue as communication channel, IBC making use of the conductivities properties of human tissue to send electrical signal from transmitter to receiver. In this paper, the authors proposed a new mathematical model for galvanic coupling type IBC based on a human limb. Starting from the electromagnetic theory, the authors treat human tissue as volume conductor, which is in analogous with the bioelectric phenomena analysis. In order to explain the mechanism of galvanic coupling type technique of IBC, applying the quasi-static approximation, the governing equation can be reduced to Laplace Equation. Finally, the analytical model is evaluated with on-body measurement for testing its performance. The comparison result shows that the developed mathematical model can provide good approximation for galvanic coupling type IBC on human limb under low operating frequencies.

A preliminary two dimensional model for Intra-body Communication of Body Sensor Networks

Intra-body communication (IBC) is an emerging and interesting communication technique for body sensor networks (BSN). It employs the human body as communication channel for transmitting signals in order to reduce electromagnetic interference and abundant cables often appeared in home health care devices. Currently researches, aim at developing the application of IBC in BSN, have been conducted by other researchers to demonstrate the feasibility and capabilities of IBC. In this paper, a preliminary two dimensional model for IBC is developed. This model attempts to provide insight of transmitting electrical signal through human body and forms a simple basis for developing IBC applications. Simulation results reveal the potential distribute in different type of biology tissues with different conductivities at low frequency and finally, experimental measurements validate the correctness of the model.

A Novel Field-Circuit FEM Modeling and Channel Gain Estimation for Galvanic Coupling Real IBC Measurements

Existing research on human channel modeling of galvanic coupling intra-body communication (IBC) is primarily focused on the human body itself. Although galvanic coupling IBC is less disturbed by external influences during signal transmission, there are inevitable factors in real measurement scenarios such as the parasitic impedance of electrodes, impedance matching of the transceiver, etc. which might lead to deviations between the human model and the in vivo measurements. This paper proposes a field-circuit finite element method (FEM) model of galvanic coupling IBC in a real measurement environment to estimate the human channel gain. First an anisotropic concentric cylinder model of the electric field intra-body communication for human limbs was developed based on the galvanic method. Then the electric field model was combined with several impedance elements, which were equivalent in terms of parasitic impedance of the electrodes, input and output impedance of the transceiver, establishing a field-circuit FEM model. The results indicated that a circuit module equivalent to external factors can be added to the field-circuit model, which makes this model more complete, and the estimations based on the proposed field-circuit are in better agreement with the corresponding measurement results.

Preliminary Modeling for Intra-Body Communication*

Intra-Body Communication (IBC) is an interesting and emerging communication methodology in recent years. Beneficial from conductive property of human body, IBC treats human body as transmission medium for sending/receiving electrical signal. As a result, interconnected cable and electromagnetic interference can be greatly reduced for devices communicated within human body. These advantages are significant for home health care system, which abundant of interconnected cables are needed. Furthermore, IBC technology also provides an alternative solution to communicate with implanted devices.

Simple electrical model and initial experiments for intra-body communications

Intra-Body Communication(IBC) is a short range “wireless” communication technique appeared in recent years. This technique relies on the conductive property of human tissue to transmit the electric signal among human body. This is beneficial for devices networking and sensors among human body, and especially suitable for wearable sensors, telemedicine system and home health care system as in general the data rates of physiologic parameters are low. In this article, galvanic coupling type IBC application on human limb was investigated in both its mathematical model and related experiments. The experimental results showed that the proposed mathematical model was capable in describing the galvanic coupling type IBC under low frequency. Additionally, the calculated result and experimental result also indicated that the electric signal induced by the transmitters of IBC can penetrate deep into human muscle and thus, provide an evident that IBC is capable of acting as networking technique for implantable devices.

Study on transfer function of intra-body communication based on quasi-static electric field modeling

Transfer function analysis plays an important role in the investigation of intra-body communication (IBC). In this paper, the voltage distribution based on the quasi-static electric field modeling of human limb for galvanic coupling IBC is analyzed, transfer function of physical channel from 1 Hz to 1 MHz is derived and proposed. The attenuation in transfer function shows that lower attenuation is obtained in frequency band from 20 kHz to 1 MHz. Moreover, rectangular pulse is utilized as the input to evaluate this system transfer function. The results in rectangular pulse response indicate separation of distance between transmitter and receiver is the major consideration in designing galvanic coupling IBC system. Finally, this paper reveals bit error rate (BER) under different distances for binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK) and 8PSK modulation schemes.

Multilayer limb quasi-static electromagnetic modeling with experiments for Galvanic coupling type IBC

Intra-body communication (IBC) is a new, emerging, short-range and human body based communication methodology. It is a technique to network various devices on human body, by utilizing the conducting properties of human tissues. For currently fast developed Body area network(BAN)/Body sensor network(BSN), IBC is believed to have advantages in power consumption, electromagnetic radiation, interference from external electromagnetic noise, security, and restriction in spectrum resource. In this article, the authors propose an improved mathematical model, which includes both electrical properties and proportion of human tissues, for IBC on a human limb. By solving the mathematical model analytically on four-layer system (skin, fat, muscle, and bone) and conducting in-vivo experiment, a comparison has been conducted.

Past Results, Present Trends, and Future Challenges in Intrabody Communication

Intrabody communication (IBC) is a wireless communication technology using the human body to develop body area networks (BANs) for remote and ubiquitous monitoring. IBC uses living tissues as a transmission medium, achieving power-saving and miniaturized transceivers, making communications more robust against external interference and attacks on the privacy of transmitted data. Due to these advantages, IBC has been included as a third physical layer in the IEEE 802.15.6 standard for wireless body area networks (WBANs) designated as Human Body Communication (HBC). Further research is needed to compare both methods depending on the characteristics of IBC application. Challenges remain for an optimal deployment of IBC technology, such as the effect of long-term use in the human body, communication optimization through more realistic models, the influence of both anthropometric characteristics and the subject’s movement on the transmission performance, standardization of communications, and development of small-size and energy-efficient prototypes with increased data rate. The purpose of this work is to provide an in-depth overview of recent advances and future challenges in human body/intrabody communication for wireless communications and mobile computing.

Biological Evaluation of the Effect of Galvanic Coupling Intrabody Communication on Human Skin Fibroblast Cells

Intrabody communication (IBC) is an effective way to connect various kinds of wearable devices attached on or under the surface of the body, but it is important to quantitatively evaluate the biological effects of the IBC signal on the human body before its further application. The research described in this paper analyzed the responses of HSF (human skin fibroblast) cells exposed to IBC electrical signals. A galvanic coupling IBC signal transmitting system was designed to expose the experimental samples with different amplitudes (from 0 V to 6 V or 0 mA to 4 mA), different frequencies (from 10 kHz to 1 MHz), and different duration times (12 h and 24 h). The control groups were unexcited. Cell morphology and activity were evaluated with inverted microscope and MTT assays. The cell survival rates of all the experiment groups were in the range of 90% to 110%. Then, the data was analyzed by t-tests to assess whether there were statistically significant differences. The results showed that values were greater than 0.05, so there were no significant differences between the experimental and control groups. Therefore, it can be concluded that the IBC signals do not have a significant effect on HSF cells.

A Novel Gait Detection Algorithm Based on Wireless Inertial Sensors

Gait event detection has been widely implemented in real-time gait monitoring devices, orthoses and FES system. Certainly, the latency and the accuracy of the gait-even detection under diversities of gait are crucial. However, due to the high detection accuracy usually comes with high time-delay, it is somewhat hard to find a trade-off between high accuracy and low latency. Therefore, this paper presents a real-time algorithm based on wireless inertial sensor placed on the shank for gait-even detection. It combines the use of the cycle-extremum and the updating threshold method to detected the heel-strike (HS), as the minimum of the flexion/extension angle, the toe-off (TO), as minimum of the angular velocity and the mid-swing (MS), as maximum of the angular velocity. The angle and angular velocity were collected from 2 subjects who imitated the patient that suffered from drop-foot for different degrees to validate the algorithm against the wireless inertial measurement system. The results showed that the proposed method achieved comparable levels of accuracy and significant lower detection delays compared with other published methods.