Equivalent-Circuit Expression of Environmental Noise Electric Fields in Intrabody Communication Channels

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

“…It was also found that attenuation is dependent on the transverse length between electrodes of the same pair, obtaining better levels of received signal by considering longer interelectrode distances. Similar computational models have later been proposed to analyze the effect of the parasitic return path [131], the influence of environmental noise [133] and real experimental conditions [134], the differences between surface-to-surface and implanted communications [130], and the use of noncontact electrodes at the transmitter [131]. A hybrid model considering both electrostatic circuit analysis and FEM model simulations has been proposed in [50] by Park et al to analyze different parameters of HBC channel such as the external coupling characteristics between the environment and the electrodes as well as the transmission performance obtained with different experimental setups comprising VNAs and miniaturized batterypowered wearable transceivers.…”

“…Thus, experimental schemes using different equipment such as oscilloscopes and signal generators, spectrum analyzers [48,160], and vector network analyzers (VNA) [161], as well as customized transceivers, have been used interchangeably [144,162]. Recently, in [50], an exhaustive study about optimal measurement configuration for HBC channel characterization using miniaturized battery-powered transceivers has been reported by Park et al In addition, another important issue in the characterization of IBC channels is the determination and quantification of environmental noise, as modeled in [133]. It is therefore necessary to harmonize and clarify the proposed setups and measurement procedures to establish an experimental methodology that allows the characteristics of the IBC channel to be identified in a systematic and accurate way.…”

“…A comprehensive noise analysis for capacitive IBC was reported by researchers from several Japanese institutions [13,14,56,133,180,[183][184][185]. They showed that IBC systems are affected by large common-mode noise from various kinds of electronic equipment in living spaces, such as lighting devices, air conditioners, liquid crystal televisions, and refrigerators [13,14].…”

“…An effective way of improving impedance balance and reducing common-mode noise in the system was connecting an additional electrode or a compact capacitor to a ground electrode, according to [13,14] (Figure 13). Two types of noise, excluding transceivers noise, are coupled to the embedded receiver [183]: radiated noise via human body [133,183,184] and conducted noise via floor ground [180]. Noisy-channel models of a capacitive IBC system with an embedded receiver situated in the vicinity of a wall was investigated by Sasaki et al in [180].…”

“…As a result, the SNR was increased. Another noise component, radiated noise, was explained in [133,184] by means of electrostatic analysis based on the method of moments. The proposed circuit model contains a total of 20 parameters, namely, 15 capacitances and 5 equivalent noise sources.…”