Intra-body Communication Research Articles

A Visible Human Data-Based Whole-Body Model for Investigating the Transmission Attenuation of Intrabody Communication

Intrabody communication (IBC) is a promising approach for realizing information transmission among various wearable or implantable devices within bodyNET. The existing IBC studies are limited to the local or abstract geometric channel model, which is limited to providing efficient channel characteristics for the various transmitting scenarios. The aim of this article is to reconstruct a whole-body model with anatomical features and combine the field-circuit model for investigating the human channel characteristics. A visible human data (VHD) is established by segmentation and 3-D reconstruction of layered tissues. The transmission attenuation was simulated and analyzed through the finite element method. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In vivo</i> experiments and phantom experiments were implemented to validate the simulation results. For the on-body communication, the transmission attenuation of the short distance was similar to the low-pass filter’s amplitude-frequency characteristics. For the implantable communication, the consistency coefficient of the attenuation between in-body to on-body and on-body to in-body was higher than 98%, indicating that the body channel is bidirectional. This work provides a repeatable and verified VHD-based whole-body model for the human channel attenuation investigation. It is an essential step for the further development of IBC, such as the transceiver design and the multinodes’ protocol for bodyNET.

An Implantable System for Neural Communication and Stimulation: Design and Implementation

Assistive technologies enable humans to enhance their abilities and restore missing or lost physiological functions. However, some pathologies, such as facial palsy, are currently treated only with invasive surgical procedures. This article introduces a novel bio-compatible and safe implantable engineered based system for neural communication and stimulation, which is able to overcome facial paralysis due to a nerve lesion by highly reducing the need for surgeries. The proposed system design leverages on ultra-low-power intra-body communication technologies to forward a signal extracted from a healthy nerve toward the injured contralater one. Preliminary prototypes are described to assess the feasibility of the proposed solution and the design of the overall communication system. Technical challenges that may be faced in the implementation of the system are discussed. The proposed solution opens the way to new opportunities for realizing innovative systems that employ unconventional communication technologies to support healthcare applications, with particular focus on neurological disease therapies.

Effects of the surrounding medium on terahertz wave scattering loss in intrabody communication

Communication among nanodevices in the human body provides accurate and localized disease detection as well as biosensing applications. Terahertz waves as a promising candidate for wireless intrabody communications could be subjected to scattering effects by different cells and particles during propagation. In this paper, we examined the intrabody scattering coefficient and path loss for three biological layers of blood, epidermis, and dermis. The results are presented and compared in two air-enclosed and tissue-enclosed approaches. We also take into account the size and shape of the particles, as well as the difference in complex refractive indices of the host medium and its scatterers. Our results emphasize how the proper assumption of the complex refractive indices of the tissue's surrounding medium could prevent the overestimation of the scattering loss and, consequently, lead to more realistic anticipation of the scattering effects.

Lithium Niobate Piezoelectric Micromachined Ultrasonic Transducers for high data-rate intrabody communication

In recent years, there has been an increased interest in continuous monitoring of patients and their Implanted Medical Devices (IMDs) with different wireless technologies such as ultrasounds. This paper demonstrates a high data-rate intrabody communication link based on Lithium Niobate (LN) Piezoelectric Micromachined Ultrasonic Transducers (pMUTs). The properties of the LN allow to activate multiple flexural mode of vibration with only top electrodes. When operating in materials like the human tissue, these modes are merging and forming a large communication bandwidth. Such large bandwidth, up to 400 kHz, allows for a high-data rate communication link for IMDs. Here we demonstrate a full communication link in a tissue phantom with a fabricated LN pMUT array of 225 elements with an area of just 3 by 3 mm square, showing data-rates up to 800 kbits/s, starting from 3.5 cm and going up to 13.5 cm, which covers the vast majority of IMDs.

A Quasi-digital QPSK Modulator Design for Biomedical Devices

For the biomedical transceiver, the data transmission is often asymmetric. At the downlink, the transceiver only needs to receive a simple command to control the operation of the external device, and the receiving data rate is low, about hundreds of Kb/s. However, data collected by external devices such as temperature sensors, pressure sensors, or cameras are often very large, which results in a transmitting data rate of several Mb/s. Therefore, a high energy-efficient modulator is needed. Compared with conventional digital modulator, analog modulator circuits have demonstrated superior energy efficiency at high data rates. This article presents a quasi-digital quadrature phase-shift keying (QPSK) modulator design realized by pure analog circuits which follows a logic design flow. The simulation results show that the system can generate a stable carrier of 64 MHz that meets intra-body communications (IBCs) requirements with a data transmission rate of 10 Mb/s. When the signal-to-noise ratios (SNRs) of the Gaussian channel is 14 dB, it can still maintain a bit error rate (BER) below 10 4 .

Fluorescent nanoparticles for reliable communication among implantable medical devices

Molecular Communication (MoCo) is a bio-inspired methodology enabling secure communication in “wave-denied” environments like intrabody communication among implantable medical devices. MoCo is based on the exchange, through fluids, of molecular messengers that carry the message instead of using electromagnetic waves. The transmitter emits the symbol by releasing a certain amount of information carrier into the carrier fluid traveling to the receiver, which, located downstream, waits for detection. This innovative approach enables secure communication between active implantable medical devices with no risk of eavesdropping or interference. Here a novel modulation method is devised, theoretically simulated, and experimentally demonstrated. The information is carried by fluorescent carbon nanoparticles. The modulation of the signal is obtained by exploiting the instability effect of an interfacial phenomenon, known as viscosity fingering, which occurs when two miscible liquids having different viscosity or strong density variation makes contact. This modulation is called “Interfacial Shift Keying” (ISK). The multinary-ISK version realized by combining multiple effects of interfacial difference has allowed secure communication in a testbed simulated bionic pancreas arrangement. Values of glucose variation in the body in the hours following a meal were successfully communicated by ISK modulated MoCo. Decoding of the symbol by machine learning methods has also been comprehensively reported.

Evaluation of the Communication Distance on Magnetically Coupled Intra-body Communication ―Comparison of Various Coupling Methods―

Evaluation of the Communication Distance on Magnetically Coupled Intra-body Communication ―Comparison of Various Coupling Methods―

A Current-Switching Technique for Intra-Body Communication With Miniaturized Electrodes.

Medical implants are required to be minimized in size to alleviate surgical pains. Battery and antenna are often the main bottlenecks in system miniaturization. Wireless power transfer (WPT) is a possible way to minimize or eliminate the battery. Medical implants with WPT often use backscattering for data communication due to its low power consumption and low hardware cost. However, the conventional backscattering approach with WPT requires a large implanted antenna to ensure a relatively high efficiency and enough signal-to-noise ratio (SNR) for demodulation. In this work, we propose a current-switching technique for intra-body communication to achieve a high SNR and data rate with a pair of small implanted electrodes. Instead of the conventional electric-field based WPT and communication, a current loop is configured in the body tissue for WPT, where a new passive-communication scheme is implemented at the same time. A prototype is implemented to validate the proposed technique, in which the implanted electrodes are designed to be as small as 200 μm × 200 μm, located 13 mm deep in the tissue. The system achieves a communication rate of 10 Mbps with a bit error rate (BER) of 8.4 ×10-4 over the 406 MHz MedRadio band, while the signal-to-blocker ratio and SNR are measured to be -35.7 dB and 12.4dB, respectively.

Ultrasonic intra-body communication using semi-guided waves through human body tissues

Body Area Network (BAN) demands a secure and low-power technology. Traditionally, RF signals were used, which suffer from high losses and lack of security. Recently, electro-quasistatic human body communication has emerged, enabling low-power communication, but somewhat susceptible to leakage. Ultrasound is presented as a promising alternative owing to its ability of propagating in water-dominated media, like the human body, besides being safe. Existing studies employ ultrasound devices for powering or communicating across tissues; either through transmitter-receiver aligned configurations (not suitable for non-line-of-sight communication) or using omnidirectional transducers, hence limiting the communication distance to only a few centimeters. This paper presents a theoretical study on confining ultrasound waves inside the human tissues (muscle, fat and skin). Through oblique incidence on the bone/muscle interface, the waves can bypass the bone (highly attenuative tissue) through total internal reflection, and be guided through water-rich body tissues. In addition, the high reflection at the skin/air interface (∼99.9%) confines most of the signal inside the body, ensuring secure communication. Simulations are performed on a simplified cylindrical-shaped human body model at 100 kHz, demonstrating the possibility of transmitting a signal over a distance of ∼1 m with losses <50 dB and leaked signal attenuation of additional >20 dB.

Analysis and Fitting of a Thorax Path Loss Based on Implantable Galvanic Coupling Intra-Body Communication

Objective: The aim of this research was to study the channel transmission characteristics of living and dead animal bodies and signal path loss characteristics of implantable communication in the axial direction. Methods: By injecting fentanyl citrate injection solution, we kept the research object (a piglet) in a comatose state and then a death state, so as to analyze the channel characteristics in each state. To analyze channel gain when using an implantable device with a fixed implantation depth and varying the axial distance, we proposed an implantable two-way communication path loss model. Results: Comparing the living-body and dead-body results showed that the channel gain difference was approximately 10dB for the same position and distance; heartbeat, pulse and breathing of the living animal contributed approximately 1dB of noise. Analyzing the calculated and experimental results of the path loss model showed that the determination correlation coefficients of the model were 0.999 and 0.998, respectively. The model prediction result and the experimental verification result also agreed closely. Conclusion: The path loss model not only fits the experimental results, but also has better predictability for those positions not measured.

What Ultrasound Can and Cannot Do in Implantable Medical Device Communications.

Modern Active Medical Implantable Devices require communications to transmit information to the outside world or other implantable sub-systems. This can include physiological data, diagnostics, and parameters to optimise the therapeutic protocol. The available options are to use optical, radiofrequency, or ultrasonic communications. However, in all cases, transmission becomes more difficult with deeper transmission through tissue. Challenges include absorption and scattering by tissue, and the need to ensure there are no undesirable heating effects. As such, this paper aims to review research progress in using ultrasound as an alternative for deep tissue communications. We provide an empirical review of the technology and communication protocols that different groups have used, as well as comparing the implications in terms of penetration depth, implant size, and data rate. We conclude that this technique has promise for deeper implants and for intrabody communications between implantable devices (intrabody networks).

A survey on energy efficiency intrabody communication techniques for wearable devices

Currently, wireless body area networks (WBANs) are developing rapidly. Miniature wearable devices which are light weight and low power consumption can be developed using modern technology. However, the WBANs research challenge is power consumption. This paper provides the two intrabody communication (IBC) methods review. The equivalent body channel models and modeling methods are analyzed. The conventional IBC WBANs architecture is reviewed and novel energy-efficient architecture and an IBC WBANs data transmission technique are proposed. The experiment was conducted in order to measure the BodyCom mobile module output power. The comparative analysis showed that the power consumption of the IBC proposed technique is 7 times lower than Bluetooth LE, and 14 times lower than ZigBee. The proposed technique can be applied in areas such as home and industrial automation, medical appliances, wearable devices, security, and internet of things.

A Splitting-Detection Joint-Decision Receiver for Ultrasonic Intra-Body Communications

Ultrasonic intra-body communication (IBC) is a promising enabling technology for future healthcare applications, due to low attenuation and medical safety of ultrasonic waves for the human body. A splitting receiver, referred to as the splitting-detection separate-decision (SDSD) receiver, is introduced for ultrasonic pulse-based IBCs, and SDSD can significantly improve bit-error rate (BER) performance over the traditional coherent-detection (CD) and energy detection (ED) receivers. To overcome the high complexity and improve the BER performance of SDSD, a splitting-detection joint-decision (SDJD) receiver is proposed. The core idea of SDJD is to split the received signal into two streams that can be separately processed by CD and ED, and then summed up as joint decision variables to achieve diversity combining. The theoretical channel capacity and BER of the SDSD and SDJD are derived for M-ary pulse position modulation ( M-PPM) and PPM with spreading codes. The derivation takes into account the channel noise, intra-body channel fading, and channel estimation error. Simulation results verify the theoretical analysis and show that both SDSD and SDJD can achieve higher channel capacity and lower BER than the CD and ED receivers with perfect channel estimation, while SDJD can achieve the lowest BER with imperfect channel estimation.

Editor's comments

Most of the more than one million cardiac pacemakers implanted each year have up to three leads that reach into the heart's chambers. The most modern pacemakers integrate all of the pacemaker functions into a small capsule that be directly implanted into the endocardium, resulting in what is known as a leadless cardiac pacemaker. However, these can typically only be used to stimulate a single chamber. By using intra-body communication, the operation of more than one leadless cardiac pacemaker can be synchronized, resulting in the ability to use this approach with multiple chambers of the heart. The paper by Mirko Maldari, Chadi Jabbour, Youcef Haddab, and Patricia Desgreys describes a system for such intra-body communication for pacemakers. The design and development of the system is described, as well as the optimization of the power usage of the system based on the signal waveform involved. The results demonstrated the telemetry-based synchronization of a dual-chamber leadless cardiac pacemaker system with minimum power consumption. This paper was based on one of the finalists for the 2021 URSI-France PhD Prize in Radio Science.

Nano-Sensor Modelling for Intra-Body Nano-Networks

In this work, the author has evaluated the propagation of electromagnetic waves inside the human tissue such as blood, skin and fat for single-path and multi-path layers according to nano sensor transmit power calculations. In particular, the propagation characteristics of the Intra-Body Nano-Network communication channel are calculated using a theoretical approach. The analysis in this paper provides an evaluation related to the path loss, bit error rate, signal to noise ratio and the channel capacity. The model is evaluated for each single-path effect and multi-path effect. The effects of human tissue for each blood, skin and fat for single-path effect and multi-path are included in the analysis. The model frequency range is chosen from 0.01 to 1.5 THz frequencies, which are ideal for designing nano sensors antennae and using THz range for communication. This paper will also guide other researchers who are working on the electromagnetic radiation performance of Intra-Body Nano-Network and Nano sensors designed at the THz range.

Galvanic Impulse Wireless Communication for Biomedical Implants

Wireless intra-body communication is a promising approach for providing efficient and secure connectivity for medical implants. The low power consumption of the electronics and the conductivity of the biological tissues facilitate the system implementation, which makes the technique more power-efficient than the traditional radio frequency wireless systems. The galvanic intra-body communication uses the electrical current for signal transmission in the conductive medium of the biological tissues. In this paper, we propose an ultra-low-power communication approach by implementing a galvanic impulse method for communication between an implant and an on-body device. The communication system is designed, manufactured with off-the-shelf electronic components, and measured in the phantom and in-vivo animal experiment. The implant power consumption is 45 μW for the data rate of 64 kbps with a bit error percentage below 0.5% for the implant depth of 14 cm. The design supports long-lasting battery-powered implant sensory and communication system.

Signal Transmission Characteristics and Biosafety Evaluation of Magnetically Coupled Intra-Body Communication using Numerical Electromagnetic Field Analysis

Signal Transmission Characteristics and Biosafety Evaluation of Magnetically Coupled Intra-Body Communication using Numerical Electromagnetic Field Analysis

Fat-IntraBody Communication at 5.8 GHz: Verification of Dynamic Body Movement Effects Using Computer Simulation and Experiments

This paper presents numerical modeling and experimental validation of the signal path loss at the 5.8 GHz Industrial, Scientific, and Medical (ISM) band, performed in the context of fat-intrabody communication (fat-IBC), a novel intrabody communication platform using the body-omnipresent fat tissue as the key wave-guiding medium. Such work extends our previous works at 2.0 and 2.4 GHz in the characterization of its performance in other useful frequency range. In addition, this paper also includes studies of both static and dynamic human body movements. In order to provide with a more comprehensive characterization of the communication performance at this frequency, this work focuses on investigating the path loss at different configurations of fat tissue thickness, antenna polarizations, and locations in the fat channel. We bring more realism to the experimental validation by using excised tissues from porcine cadaver as both their fat and muscle tissues have electromagnetic characteristics similar to those of human with respect to current state-of-art artificial phantom models. Moreover, for favorable signal excitation and reception in the fat-IBC model, we used topology optimized waveguide probes. These probes provide an almost flat response in the frequency range from 3.2 to 7.1 GHz which is higher than previous probes and improve the evaluation of the performance of the fat-IBC model. We also discuss various aspects of real-world scenarios by examining different models, particularly homogeneous multilayered skin, fat, and muscle tissue. To study the effect of dynamic body movements, we examine the impact of misalignment, both in space and in wave polarization, between implanted nodes. We show in particular that the use of fat-IBC techniques can be extended up in frequency to a broadband channel at 5.8 GHz.

A Leg Phantom Model Based on the Visible Human Data for Intra-Body Communication

Intra-body communication (IBC) is an alternative method for communication of devices in body area networks. The existing research is mainly focused on on-body (OB) channel modeling, transceiver design, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> experiments. However, the difficulty arises in carrying out long-term <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> experiments for investigating the human channel characteristics in OB or in-body (IB) IBC channels, since the repeatability of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> experiments shows inconsistency. In this paper, a multi-layer leg model with realistic shape was designed based on visible human data (VHD) images. Then, novel mixtures with the approximate conductivities of leg tissues were designed and used to fabricate leg phantoms, via several pairs of 3D-printed molds. Finally, the efficiency of the leg phantoms was validated by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> experiments through the high similarity of voltage gain versus distance characteristic of the OB channel. Both conditions featured the same trend, that is, they decreased first and then stabilized. The leg phantom was adopted to explore the channel characteristics of the IB channel. The results indicate that the voltage gain versus distance curve of the OB to IB channel was nearly reciprocal. In summary, the VHD-based leg phantom provides a reusable experiment platform for the IBC research, especially for the case of implantable channels.

New Contact Sensorization Smart System for IoT e-Health Applications Based on IBC IEEE 802.15.6 Communications.

This paper proposes and demonstrates the capabilities of a new sensorization system that monitors skin contact between two persons. Based on the intrabody communication standard (802.15.6), the new system allows for interbody communication, through the transmission of messages between different persons through the skin when they are touching. The system not only detects if there has been contact between two persons but, as a novelty, is also able to identify the elements that have been in contact. This sensor will be applied to analyze and monitor good follow-up of hand hygiene practice in health care, following the “World Health Organization Guidelines on Hand Hygiene in Health Care”. This guide proposes specific recommendations to improve hygiene practices and reduce the transmission of pathogenic microorganisms between patients and health-care workers (HCW). The transmission of nosocomial infections due to improper hand hygiene could be reduced with the aid of a monitoring system that would prevent HCWs from violating the protocol. The cutting-edge sensor proposed in this paper is a crucial innovation for the development of this automated hand hygiene monitoring system (AHHMS).