A Brief Survey on Human Body Communication
for Healthcare Applications
Jian Feng Zhao1* and Xi Mei Chen2
1School of Automotive and Transportation Engineering, Shenzhen Polytechnic, China
2Baoan Urban Renewal Authority, China
Submission: October 01, 2017; Published: October 25, 2017
*Corresponding author: Jian Feng Zha, School of Automotive & Transportation Engineering, Shenzhen Polytechnic, Shenzhen, China,
How to cite this article: J F Zhao, X M Chen. A Brief Survey on Human Body Communication for Healthcare Applications. Curr Trends Biomedical Eng
& Biosci. 2017; 10(1): 555778. DOI: 10.19080/CTBEB.2017.10.555778.
Human body communication (HBC), which utilizes the human body as communication channel to transmit physiological signal, is more reliable and less prone to interference than the wireless transmission techniques such as Bluetooth, Wi-Fi etc. HBC 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. A brief survey on the development of HBC, which includes the signal propagation mechanisms, channel characteristics and communication performance are summarized and addressed. Moreover, the experimental issues, such as electrodes and grounding strategies are also discussed. Finally, the recommended future studies are provided.
Keywords: Human body communication; Body area network; Signal propagation model; Channel characteristics; Communication
In the history of human beings, people had great interests on body tissues. Many researchers devoted their efforts and thoughts to investigate the body tissue (i.e. muscle) and their electrical properties and biomechanics. There are generally two
research directions in bioelectrical assessment of muscle, one is to study the electrical signal originated from body tissue, and another is to investigate the properties of tissue by applying electrical signals.
The connection between electricity and muscle contraction
was first observed by the Italian physician Luigi Galvanic in
the mid-1780s. Luigi Galvanic found that recently-dead muscle
tissue can respond to external electrical stimuli. Since then,
more and more researchers investigated the response of human
tissue to electric current. The early extensive literature reviews
on dielectric properties have been provided by Geddes & Baker
, who summarized the early reports on the specific resistance
of tissues. Later, the intensive research on tissue dielectric
property was reported by Gabriel . And further experiments
were conducted by Gabriel et al. . To study the dielectric
properties of human and animal tissue in the frequency range
10Hz to 20GHz . Basing on these measurements, a parametric
model with four Cole-Cole type dispersions was developed
to describe the dielectric properties of tissue as a function of
frequency . These electrical properties have been utilized by
the researchers to facilitate the recent research and applications.
For instance, electrical impedance tomography (EIT) has been
developed to image the internal organs and structure of body
for medical diagnosis, electrical stimulation has been adopted
for medical therapy and prosthesis. Until 1995, human body
as a transmission medium was proposed to be utilized for data
transmission. This type of telemetry, called capacitive coupling
HBC , was developed to enable data transmission on or
around the human body. The development of HBC is background
on body area network (BAN), which is introduced in around
2001 and comes to refer the healthcare systems wherein data
communication is entirely within the immediate proximity of
human body . The deployment of BAN with HBC is shown
in Figure 1. The sensor nodes including both the on-body and
in-body nodes (implantable devices), perform the monitoring
function. The physiological data from these nodes are delivered
privately and reliably to a relay node or aggregator mounted on
the body, such as a smart-watch or smart wristband. The data
are then forwarded to the hub and the central control point,
from where the data are available to hospital, professional staff
and emergency center or for personal usage. It is expected that
the future medical system with BAN can provide the diseases
with early discovery, early detection, early intervention and
treatment, which can help to alleviate the prevalence of chronic
diseases (e.g. heart diseases, diabetics, strokes) and escalating
of aging population, which have become public health concerns
and challenges of healthcare system.
Generally, HBC can be implemented in two ways: capacitive
coupling method and galvanic coupling method. Generally,
capacitive coupling HBC, which requires ground electrodes
floating in air to couple the environment as signal return path,
operates in higher frequency around 100MHz to 1GHz, and
transmits in longer distance even to 200cm. Galvanic coupling
HBC, where all electrodes are tissue-attached, operates in lower
frequency around 100kHz to 10MHz, and the attempt to transmit
physiological data for implantable devices has been achieved .
The pioneer researches of HBC focused on the feasibility of
implementing HBC. After that, the signal propagation models
were emerging to investigate the signal propagation mechanism
and channel characteristics. Later, experiments and prototypes
were developed to investigate their communication performance.
Since the first attempt of HBC, the signal propagation models,
such as circuit models including distributed circuit model 
and RC model , quasi-static model , FEM models ,
FDTD model  and so on, are proposed by research groups
to explain the signal transmission mechanism, which can help to
exploit the unknown channel characteristics. The models in the
early state consider only the human body and electrodes. Later,
the models considering the effect from the environmental effect
such parasitic capacitance were developed and then higher
matches between model and measurement were achieved.
Anyway the discrepancies between the model and measurement
results do exist. Reliability of the results that are reported in
the published papers may vary, because not all of the issues
have been rigorously discussed and verified in the research
Meanwhile, the experimental methods or prototypes are
developed to investigate the channel transmission characteristics
and communication performance, the suitable transmission
parameters for monitoring applications are also investigated in
these experiments. The models and communication performance,
as well as the future research directions are shown Figure 2.
Accompanying with the measurements, the experimental issues
such as electrode types (Ag/Agcl electrode, copper electrodes,
pt electrodes), grounding strategies using balun or differential
active probes are also investigated in literatures.
The new application of HBC in healthcare has also been
explored. For instance, galvanic coupled HBC signal propagation
has been utilized to evaluate the body fluid  and help to aid
diagnosis and treatment of fluid disorders such as lymph edema.
The human limb galvanic coupled system has been adopted to
perform the joint angle estimation  which can be applied in
prosthesis control and gait analysis.
The measurements show that HBC channel is subjected
dependent. To achieve the practical applications, building the
reality HBC system with subject-independent is challenged.
Moreover, the monitored data in the HBC nodes are raw and
rough; it is challenged to fuse these data to achieve in-depth
information and deduced information. Moreover, combining
the data from multiple sensors such as ECG, blood sensor to
achieve a reliable and directly result for the general human is
Although human body communication (HBC) has been
around for more than two decades, we should realize that the
technology is still at its infancy. More affects are required to
be devoted in the major commercial application of HBC, which
is not achieved yet, and there is no feedback from practical
applications that usually clarify technical issues that really need
to be solved. Therefore, building the commercial HBC system
with subject-independent is a recommended research direction.
Moreover, developing the HBC model to implantable devices are
suggested. Finally, data fusions among HBC nodes to achieve
more healthcare informatics are also recommended.