Wearable ECG Based on Impulse-Radio-Type Human Body Communication

Abstract

Human body communication (HBC) provides a promising physical layer for wireless body area networks (BANs) in healthcare and medical applications, because of its low propagation loss and high security characteristics. In this study, we have developed a wearable electrocardiogram (ECG) which employs impulse radio (IR)-type HBC technology for transmitting vital signals on the human body in a wearable BAN scenario. The HBC-based wearable ECG has two excellent features. First, the wideband performance of the IR scheme contributed to very low radiation power so that the transceiver is easy to satisfy the extremely weak radio laws, which does not need a license. This feature can provide big convenience in the use and spread of the wearable ECG. Second, the realization of common use of sensing and transmitting electrodes based on time sharing and capacitive coupling largely simplified the HBC-based ECG structure and contributed to its miniaturization. To verify the validity of the HBC-based ECG, we evaluated its communication performance and ECG acquisition performance. The measured bit error rate, smaller than 10 at 1.25 Mb/s, showed a good physical layer communication performance, and the acquired ECG waveform and various heart-rate variability parameters in time and frequency domains exhibited good agreement with a commercially available radio-frequency ECG and a Holter ECG. These results sufficiently showed the validity and feasibility of the HBC-based ECG for healthcare applications. This should be the first time to have realized a real-time ECG transmission by using the HBC technology.

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

“…A group from NTT Human Interface Laboratories was focused on connecting electronic devices in everyday life by a simple touch [15,55,57] and developed an indoor wireless-like networking and positioning system for connecting portable and wearable devices (home and office appliances) to the network while the user stands or walks on the floor [54,56,[58][59][60]. In biomedical applications field, IBC was employed in various general biomedical systems [66,67,70,71,85,86,95,96,190] or specifically for ECG [87,93,94], EMG [68,69], and human posture [83,84] monitoring, as well as for monitoring and controlling artificial hearts and other artificial organs in the body [77,78]. IBC systems developed for the characterization of IBC channel and human body as a signal transmission medium [19, 20, 33, 41, 61-65, 72-76, 79-82, 88, 89, 93, 94] are mostly built around DDS or FPGA circuits for signal generation at one or in the range of frequencies and for the detection of received signal power at the receiver end.…”

Analysis of In-to-Out Wireless Body Area Network Systems: Towards QoS-Aware Health Internet of Things Applications

“…The average BER performance of the four selected modulation methods is shown in Figure 5. At the receiver, AWGN is the dominant noise source [5] so we consider only thermal noise with one-sided power spectral density (PSD) [5,[29][30][31]:…”

“…In this paper, typical transmitting power values of 1, 10 and 25 µW are selected for further research and discussions. Given the high QoS requirements of healthcare communication systems, similar to other I2O body communication systems, a predetermined BER threshold of 10´3 was selected to ensure the communication performance is acceptable [5,[28][29][30][31]. According to Figure 5, the threshold SNR thr values for BPSK, QPSK, 16QAM and 16PSK are approximately 11 dB, 13 dB and 15.5 dB and 18 dB, respectively.…”

“…Constraint (28) regulates the number of data packets that need optimizing due to the limited packet handing capacity at the receiver. Similarly, Constraint (29) demonstrates that the packet arrive rate γ arr S should be less than the packet transmit rate γ dep S and this can reduce the queuing delay τ queue S . Constraint (30) points out that BER should be higher than a predetermined BER threshold, otherwise the rate of dropped packets will increase τ Proc S .…”

A dual-band coil antenna for MHz band on-body wireless body area networks

“…In [11][12], a 10 -60 MHz IR transceiver was proposed and used for Electrocardiogram (ECG) based human body and implantable medical communication. Due to the transceiver's wide transmission band, high data rates and interference immunity can be realized.…”