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Li J.W.,University of Macau | Chen X.M.,University of Macau | Mak P.U.,University of Macau | Mak P.U.,Laboratory of Medical Instrumentation and Pharmaceutical Technology of Fujian Province | And 9 more authors.
BMEiCON 2014 - 7th Biomedical Engineering International Conference | Year: 2015

Intra-body Communication (EBC), which utilizes the human body act as communication channel, offers a novel technology for information exchange in Biomedical Engineering (BME) field. Galvanic-type IBC has been a promising choice for IBC because of its advantages like lesser interference to the nearby environment and lower frequency operation. Bit Error Rate (BER) is a standard figure of merit to indicate the error performance of communication channel. For low frequency and low transmit rate in galvanic-type IBC, the traditional method of BER measurement is time-consuming. Furthermore, to measure through the human body for such a long time is neither practical nor feasible without physiological changes. In order to evaluate the error performance of galvanic-type IBC, this paper presents an alternate approach to investigate BER values of the channel and verifies its behaviors with human lower arm experiment. After comparing the experimental results and theoretical calculation based on ideal Additive White Gaussian Noise (AWGN) channel, it is found that their traces have similar agreement. Besides, the experimental phenomenon indicates the assumptions that channel noise of galvanic-type IBC has AWGN characteristic are reasonable and applicable in some regions. © 2014 IEEE.

Chen X.M.,Macau University of Science and Technology | Mak P.U.,University of Macau | Mak P.U.,Aurora University | Pun S.H.,University of Macau | And 9 more authors.
2013 IEEE 6th International Conference on Advanced Infocomm Technology, ICAIT 2013 | Year: 2013

Transfer function of intra-body communication (IBC) helps the understanding of signal transmission mechanism and hints for efficient communication system design. In this paper, transfer function with phase information based on quasi-static electromagnetic (EM) field modeling for a galvanic-type IBC limb is briefly reviewed. Then the compensation factor, which is calculated by the minimum mean square error (MMSE) method, is introduced to correct the inevitable deviation in actual shapes of human limb and electrical properties of tissues. To verify the effectiveness of correction factor, the square wave response is calculated and experimentally measured. Eventually, our results demonstrate good agreement between theoretical calculation and experimental measurement. © 2013 IEEE.

Li J.W.,University of Macau | Chen X.M.,University of Macau | Pun S.H.,University of Macau | Pun S.H.,Laboratory of Medical Instrumentation and Pharmaceutical Technology of Fujian Province | And 9 more authors.
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2013

Bit error rate (BER), which indicates the reliability of communicate channel, is one of the most important values in all kinds of communication system, including intra-body communication (IBC). In order to know more about IBC channel, this paper presents a new method of BER estimation for galvanic-type IBC using experimental eye-diagram and jitter characteristics. To lay the foundation for our methodology, the fundamental relationships between eye-diagram, jitter and BER are first reviewed. Then experiments based on human lower arm IBC are carried out using quadrature phase shift keying (QPSK) modulation scheme and 500 KHz carries frequency. In our IBC experiments, the symbol rate is from 10 Ksps to 100 Ksps, with two transmitted power settings, 0 dBm and -5 dBm. Finally, the BER results were obtained after calculation by experimental data through the relationships among eye-diagram, jitter and BER. These results are then compared with theoretical values and they show good agreement, especially when SNR is between 6 dB to 11 dB. Additionally, these results demonstrate assuming the noise of galvanic-type IBC channel as Additive White Gaussian Noise (AWGN) in previous study is applicable. © 2013 IEEE.

Chen X.M.,University of Macau | Mak P.U.,University of Macau | Mak P.U.,Laboratory of Medical Instrumentation and Pharmaceutical Technology of Fujian Province | Pun S.H.,University of Macau | And 7 more authors.
Sensors (Switzerland) | Year: 2012

Intra-Body Communication (IBC), which modulates ionic currents over the human body as the communication medium, offers a low power and reliable signal transmission method for information exchange across the body. This paper first briefly reviews the quasi-static electromagnetic (EM) field modeling for a galvanic-type IBC human limb operating below 1 MHz and obtains the corresponding transfer function with correction factor using minimum mean square error (MMSE) technique. Then, the IBC channel characteristics are studied through the comparison between theoretical calculations via this transfer function and experimental measurements in both frequency domain and time domain. High pass characteristics are obtained in the channel gain analysis versus different transmission distances. In addition, harmonic distortions are analyzed in both baseband and passband transmissions for square input waves. The experimental results are consistent with the calculation results from the transfer function with correction factor. Furthermore, we also explore both theoretical and simulation results for the bit-error-rate (BER) performance of several common modulation schemes in the IBC system with a carrier frequency of 500 kHz. It is found that the theoretical results are in good agreement with the simulation results. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

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