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This study investigates the influence of human body movement on signal attenuation during intrabody communication (IBC) for body area network (BAN) applications. While recent studies have shown channel loss measurements for IBC caused by upper limb mobility, these attenuations have yet to be addressed with respect to both upper and lower body limbs...
Context in source publication
Context 1
... measurements were firstly carried out without connecting any electrodes to the body (propagation through the air). Then, in the second step, electrodes were attached to the forearm (intra-body propagation). Figure 3 shows a comparison of human body and air path losses. Below 84 MHz, a lower attenuation is observed when the signal is propagated through the body channel compared to that obtained for the signal transmitted through the air. This means that the signal prefers to travel through the human body in this frequency range. Above 84 MHz, however, the signal through the air has less attenuation in some points compared to that of the signal propagating through the body. Therefore, the antenna effects of the connecting wires need to be taken into account at frequencies above 84 MHz. ...
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Citations
... From Fig. 7, it can be found that the variation range of path loss may reach 30 dB depending on the posture, and the shadowing increases the path loss significantly. This tendency is the same as in [21] where the reason for path loss variations during different body postures is explained to be due to the limb joints and limb movement. The limb joints produce shadowing and thus increase the path loss. ...
Human body communication (HBC) technology is attracting a lot of attention for monitoring vital data and controlling wearable robot. In this paper, we focused on electroencephalogram (EEG) signal transmission from head to wrist in the 10-60 MHz HBC band. This is based on an idea to transmit an EEG signal to control a wearable robot. First, we clarified the basic transmission mechanism and characteristics using a highly simplified human body model. Next, we performed a detailed path loss analysis by finite difference time domain simulation using an anatomical human body model with various postures. Based on the analysis results, we identified the optimum transmitter position on the head and developed an impulse radio transceiver for verifying the feasibility of the technique. The results show that the developed transceiver can provide a data rate of 10 Mbps and the bit error rate can be kept below 10-3 for transmitting the EEG signals from the head to the wrist. Experimental validation with a bio-equivalent gel phantom also demonstrated high feasibility of transmitting the EEG signals along the human arm.
... Other impedances between parts of an IBC channel are mostly capacitive, and include [39,159,160]: crosscapacitances between transmitter (TX) and receiver (RX) electrodes, capacitance between electrodes and environment, capacitances between body and environment (40 pF-150 pF [159,160,175,176], 110 pF [177], up to 3.9 pF [178]). All these impedances vary with chosen electrode configuration, environment, and body position, and their influence was proven in measurements of IBC channel gain [15,41,157,173,175,[179][180][181][182][183]. For in-body devices (in in-body to in-body (IB2IB) and in-body to on-body (IB2OB) channels), parameters of circuit models are difficult to measure but can be extracted from simulation results. ...
... However, for obtaining reliable results these measurements should be repeated using small batterypowered devices and tested on a large group of individuals, in order to analyze the influence of anthropometric properties of a subject. It is expected that in capacitive IB2OB and IB2IB channels an intersubject variability (anthropometrical and bioelectric properties of a subject) will have higher impact on measurement results than in the case of a capacitive OB2OB channel (for which it is almost negligible [13]), as is the case with galvanic IBC channels [15,180,201]. ...
In recent years there has been an increasing need for miniature, low-cost, commercially accessible, and user-friendly sensor solutions for wireless body area networks (WBAN), which has led to the adoption of new physical communication interfaces providing distinctive advantages over traditional wireless technologies. Ultra-wideband (UWB) and intrabody communication (IBC) have been the subject of intensive research in recent years due to their promising characteristics as means for short-range, low-power, and low-data-rate wireless interfaces for interconnection of various sensors and devices placed on, inside, or in the close vicinity of the human body. The need for safe and standardized solutions has resulted in the development of two relevant standards, IEEE 802.15.4 (for UWB) and IEEE 802.15.6 (for UWB and IBC), respectively. This paper presents an in-depth overview of recent studies and advances in the field of application of UWB and IBC technologies for wireless body sensor communication systems.
... Signal transmission and its quality may be influenced by various factors, with different works and publications highlighting the impact of multiple natural bodily effects in IBC. They include: limb joints and movement in capacitive coupling [19], [20], limb gestures on galvanic coupling [21], [22], muscle stress [23], body movement [24], human skin fibroblast cells [25], body mass index [26], and differing fat tissue thicknesses [27]. However, the fat-IBC technique reliability has only been looked into by several works in the context of parameters capable of influencing the channel's performance. ...
The potential offered by intra-body communication (IBC) over the past few years has resulted in a spike of interest for the topic, specifically for medical applications. Fat-IBC is subsequently a novel alternative technique that utilizes fat tissue as a communication channel. This work aimed to identify such transmission medium and its performance in varying blood-vessel systems at 2.45 GHz, particularly in the context of IBC and medical applications. It incorporated three-dimensional (3D) electromagnetic simulations and laboratory investigations that implemented models of blood vessels of varying orientations, sizes, and positions. Such investigations were undertaken by using ex-vivo porcine tissues and three blood-vessel system configurations. These configurations represent extreme cases of real-life scenarios that sufficiently elucidated their principal influence on the transmission. The blood-vessel models consisted of ex-vivo muscle tissues and copper rods. The results showed that blood vessels crossing the channel vertically contributed to 5.1 dB and 17.1 dB signal losses for muscle and copper rods, respectively, which is the worst-case scenario in the context of fat-channel with perturbants. In contrast, blood vessels aligned-longitudinally in the channel have less effect and yielded 4.5 dB and 4.2 dB signal losses for muscle and copper rods, respectively. Meanwhile, blood vessels crossing the channel horizontally displayed 3.4 dB and 1.9 dB signal losses for muscle and copper rods, respectively, which were the smallest losses among the configurations. The laboratory investigations were in agreement with the simulations. Thus, this work substantiated fat-IBC signal transmission variability in the context of varying blood vessel configurations.
... Fujii et al. [42] concluded that existence of the ground electrode can be quite effective in transmitting the signal because it enables the impedance matching between the signal generator and the human body [42]. In both capacitive coupling and galvanic coupling, it has been shown that the attenuation of the body channel can be much lower than that of the air channel in frequencies up to 100 MHz [68,150] (below 84 MHz according to Seyedi and Lai [151]). In galvanic coupling the received signal has less dependence on the environment [145]. ...
... Limb joint effects on IBC communication were extensively studied by Seyedi et al. [27,151,168]. In [27,168], the effects of the joint presence and joint angle (45 ∘ , 90 ∘ , 135 ∘ , and 180 ∘ ) on the IBC were studied. ...
... As expected, capacitive coupling was more sensitive to limb joint position, but galvanic coupling was more dependent on body composition (intrasubject variability). In [151], the study was extended to include an elbow and knee joint, at 20 cm transmitter-receiver distance, and similar conclusions were drawn. For the capacitive coupling, the minimum attenuation was observed at around 57.4 MHz and the differences between joint and no-joint conditions at this frequency were 2.1 dB and 1.5 dB for the elbow and knee joints, respectively. ...
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.
... From the experimental investigation, it was found that the large scale body behavior, such walking, sitting, and standing, has little effect on the channel [54,55]. The joint behavior, such as joint flexion or extension, can cause gain variate in 2∼5 dB [56,57], while phase is little affected [57]. The channel characteristics' analysis is shown in Table 3. ...
... Higher gain in trunk and back [54] High-pass profile [45] High-pass profile [59] Decrease [45] Linear channel [59] AWGN [41,59,92] Dynamic body behavior Not sensitive in sitting & waling [54] Increase as joint flexion [56] Joints and biceps muscle have a great effect [57] Decrease trend [57] Not sensitive by movement [57] Non AWGN [57] transmission power) were adopted to achieve different data rates. For capacitive coupling HBC, narrowband modulation on-off keying (OOK) and wideband signaling direct sequence spread spectrum (DSSS) were examined in [17]. ...
Human body communication (HBC), which uses the human body tissue as the transmission medium to transmit health informatics, serves as a promising physical layer solution for the body area network (BAN). The human centric nature of HBC offers an innovative method to transfer the healthcare data, whose transmission requires low interference and reliable data link. Therefore, the deployment of HBC system obtaining good communication performance is required. In this regard, a tutorial review on the important issues related to HBC data transmission such as signal propagation model, channel characteristics, communication performance, and experimental considerations is conducted. In this work, the development of HBC and its first attempts are firstly reviewed. Then a survey on the signal propagation models is introduced. Based on these models, the channel characteristics are summarized; the communication performance and selection of transmission parameters are also investigated. Moreover, the experimental issues, such as electrodes and grounding strategies, are also discussed. Finally, the recommended future studies are provided.
... The principle of IBC is based on the transmission of coupled electric fields to the body using human tissue [14]. Signal coupling to the body can be classified into two conceptually different approaches: capacitive coupling (electric field) and galvanic coupling [15]. ...
Intrabody communication (IBC) is a promising data communication technique for body area networks. This short-distance communication approach uses human body tissue as the medium of signal propagation. IBC is defined as one of the physical layers for the new IEEE 802.15.6 or wireless body area network (WBAN) standard, which can provide a suitable data rate for real-time physiological data communication while consuming lower power compared to that of radio-frequency protocols such as Bluetooth. In this paper, impulse radio (IR) IBC (IR-IBC) is examined using a field-programmable gate array (FPGA) implementation of an IBC system. A carrier-free pulse position modulation (PPM) scheme is implemented using an IBC transmitter in an FPGA board. PPM is a modulation technique that uses time-based pulse characteristics to encode data based on IR concepts. The transmission performance of the scheme was evaluated through signal propagation measurements of the human arm using 4- and 8-PPM transmitters, respectively. 4 or 8 is the number of symbols during modulations. It was found that the received signal-to-noise ratio (SNR) decreases approximately 8.0 dB for a range of arm distances (5–50 cm) between the transmitter and receiver electrodes with constant noise power and various signal amplitudes. The SNR for the 4-PPM scheme is approximately 2 dB higher than that for the 8-PPM one. In addition, the bit error rate (BER) is theoretically analyzed for the human body channel with additive white Gaussian noise. The 4- and 8-PPM IBC systems have average BER values of 10⁻⁵ and 10⁻¹⁰, respectively. The results indicate the superiority of the 8-PPM scheme compared to the 4-PPM one when implementing the IBC system. The performance evaluation of the proposed IBC system will improve further IBC transceiver design.
... However, the effects of different gestures on the communication performance of IBC channel have not been fully discussed yet. Few empirical measurements [12][13][14][15] have been conducted to investigate this issue. For instance, channel attenuation was found to be less influenced by the whole body motions such as sitting, standing and walking [16,17]. ...
... The flexion of forearm caused channel gain in the upper limb capacitive coupling IBC channel vary around 2 dB [15]. It was found that with small transversal distance between electrodes, the performance of galvanic coupling method was more susceptible to the body composition while capacitive coupling method was affected by motion [13], the flexion of elbow joint (from downward to 90°) resulted in 5 dB attenuation decrease [14]. However, with large transversal distance between electrodes, wherein better attenuation results would be obtained for galvanic coupling method [16], the effects of different gestures are not yet investigated. ...
... For the lower extremity case, more than 3 dB is suffered from the the knee joint. Similar results are reported in [14]. This is mainly due to the large area of bone and seldom muscle in joint, which hinders the electric field penetration and electric current transfer. ...
Background
Intra-Body Communication (IBC), which utilizes the human body as the transmission medium to transmit signal, is a potential communication technique for the physiological data transfer among the sensors of remote healthcare monitoring system, in which the doctors are permitted to remotely access the healthcare data without interrupt to the patients’ daily activities.
Methods
This work investigates the effects of human limb gestures including various joint angles, hand gripping force and loading on galvanic coupling IBC channel. The experiment results show that channel gain is significantly influenced by the joint angle (i.e. gain variation 1.09–11.70 dB, p < 0.014). The extension, as well as the appearance of joint in IBC channel increases the channel attenuation. While the other gestures and muscle fatigue have negligible effect (gain variation <0.77 dB, p > 0.793) on IBC channel. Moreover, the change of joint angle on human limb IBC channel causes significant variation in bit error rate (BER) performance.
Conclusions
The results reveal the dynamic behavior of galvanic coupling IBC channel, and provide suggestions for practical IBC system design.
The need for increasingly energyefficient and miniaturized bio-devices for ubiquitous health monitoring has paved the way for considerable advances in the investigation of techniques such as intrabody communication (IBC), which uses human tissues as a transmission medium. However, IBC still poses technical challenges regarding the measurement of the actual gain through the human body. The heterogeneity of experimental setups and conditions used together with the inherent uncertainty caused by the human body make the measurement process even more difficult.
The objective of this work, focused on galvanic coupling IBC, is to study the influence of different measurement equipments and conditions on the IBC channel.
different experimental setups have been proposed in order to analyze key issues such as grounding, load resistance, type of measurement device and effect of cables. In order to avoid the uncertainty caused by the human body, an IBC electric circuit phantom mimicking both human bioimpedance and gain has been designed. Given the low-frequency operation of galvanic coupling, a frequency range between 10 kHz and 1 MHz has been selected.
the correspondence between simulated and experimental results obtained with the electric phantom have allowed us to discriminate the effects caused by the measurement equipment.
this study has helped us obtain useful considerations about optimal setups for galvanic-type IBC as well as to identify some of the main causes of discrepancy in the literature.
