MSc thesis project proposal

[2018] Human Body Communication (HBC) System for Wireless Body Area Networks (WBANs)

Project outside the university

Erasmus Medical Center, Rotterdam
1. Introduction:

Human Body Communication (HBC) seems a promising technique but needs more research before being able to be used in a WBAN. Advantages:
• Very low power
• Inherit security properties
• Less interference than conventional RF communication
• Relative high data rates possible

2. Types:

There are roughly three types of HBC (see Figure):
• Galvanic coupling: Two electrodes are attached to the body to transmit the signal, and the signal is considered as
being electromagnetic waves. This is also called the waveguide type HBC.
• Electrostatic coupling: Here the return path is formed by electrical coupling between the electrodes through an
external ground through the air, while the signal transmits through the body from transmitter to receiver.
• Electric coupling: Electrodes are attached to the body at two points, while the loop is closed by a physical ground
wire. This is actually not a wireless solution.
 
3. Transceivers:

The authors of [1] have developed a transmitter and receiver using of-the-shelf FM IC’s which use a carrier frequency of 10.7 MHz. They also explain that the most optimal frequencies for HBC are ca. 5 MHz, 10-11MHz and 16-21 MHz.
Others use function generators to transmit data (say waveforms), or custom designed chips.

4. Possibilities:

One or more options could be incorporated in the project:
• Design small form-factor transceiver: Like [1], we could design a PCB with two leads for communication using off-the-shelf FM transceivers or encoders and mixers, incorporating the galvanic coupling type HBC. This has as advantage over a large setup (with function generators etc.) that it is easier to test on a real human and looks better as
prototype.
• Integrate ECG measurement: There are dedicated low-power small form-factor IC’s which can measure bio-potential signals, e.g. TI’s ADS1291. The challenge is how to share the transceiver leads with the ECG measurement.
• Implement IEEE 802.15.6 communication: Probably there are libraries which we can use, but getting this to work can have different challenges when using HBC compared to RF.
• Evaluate QoS/BER/ECG quality: Evaluate HBC communication and ECG measurements.
• Reconstruct ECG signal: Reconstruct a pseudo multi-lead ECG using multiple single-lead measurements. Not sure whether this is possible at all.

5. What’s the novelty:

The novelty regarding this thesis topic can be three-fold:
• Systems that actually use HBC as communication for data are scarce, using HBC for data communication is a novelty on it’s own.
• Combining ECG measurements is also a new phenomenon with possibilities for authorization, identification etc.
• Most HBC publications only mention two nodes that communicate, a sender and a receiver. We can target at multiple nodes.

6. Possible research questions:

• Can we use Human Body Communication for a low power multi-node Wireless Body Area Network?
• Is Human Body Communication stable enough for all-day use in a Wireless Body Area Network?

References:

[1] K. Hachisuka, A. Nakata, T. Takeda, K. Shiba, K. Sasaki, H. Hosaka, and K. Itao, “Development of wearable intra-body communication devices,” Sensors and actuators A: physical, vol. 105, no. 1, pp. 109–115, 2003.

Assignment

See '4. Possibilities' above.

Requirements

Knowledge of Signal processing, Digital/Analog communication systems and PCB design.

Contact

dr.ir. Christos Strydis

Bioelectronics Group

Department of Microelectronics

Last modified: 2019-03-01