Body-Coupled Communication for Body Area Networks (BCC)

The goal of the project is to investigate Body-Coupled Communication for Body Area Networks, and take this technology to the next TRL. We plan to achieve this goal through experimental research and measurement-based modeling. The advantage of BCC compared to conventional wireless networking solutions technologies such as WiFi and BLE is greater privacy and less electromagnetic interference; and potentially in the future, also better energy efficiency.

Main objectives of the project are:

The project is funded by Latvian Councils of Science, Project No: lzp-2020/1-0358.

What are the benefits of the project?

The BCC technology studied in the project offers a safer and more energy-efficient way to transmit data over short distances, collected from biometric sensors.

Safer, because the BCC signal spreads minimally through the air. Therefore, hackers and other third parties will not be able to intercept this signal from a distance. Although WiFi and Bluetooth signals transmitted through the air are encrypted, in practice, security “holes” are occasionally found in these technologies, which hackers can exploit. It is safer simply not to radiate the signal through the air.

More energy-efficient, because transmitting an electromagnetic signal through the air requires more energy than transmitting a BCC signal through the body.

This is a scientific project, so no new products or services are directly expected as an outcome; the main result of the project will be knowledge. This knowledge will allow for the future production of wearable devices and sensors that are safer and have longer battery life. Since the knowledge will be obtained at an institute in Latvia, Latvian residents and companies will be in the best starting positions to use this knowledge and turn it into economic benefits. 

Which specific sensors will be used in the project?

Currently, there are no ready, commercially available sensors capable of “communicating” using BCC technology. In any case, the project does not provide for installing or testing specific sensors; its goal is the improvement of communication technology.

However, applications are mentioned in the project, as this technology’s communication will be improved for specific use cases, which implies targeting specific types of sensors. This is because different sensor types impose different requirements, such as data volume, delay, and reliability. By analogy, wireless video transmission requires WiFi, while audio transmission can work with Bluetooth.

How can data be transmitted through the human body?

BCC is a technology that allows wireless data transmission. Other, more widely known wireless transmission methods are WiFi, Bluetooth, and mobile networks. All these technologies use electromagnetic radiation to transmit data. There are also other short-range wireless data transmission methods, such as RFID, which is used in contactless bank cards, e-tickets, and elsewhere for object identification. A similar technology is NFC (Near Field Communication) found in mobile phones.

Both BCC and the more widely known RFID and NFC technologies use the near field. In physics, the near field refers to the region close to the transmitter, where the electric and magnetic fields exist as two separate components. In the far field, they merge into a single electromagnetic radiation, which, depending on the frequency, can be radio waves, light, or other types of radiation.

The physics of the near electric field allows effective communication over short distances, such as at the scale of the human body. Unlike WiFi and Bluetooth, the BCC signal spreads poorly through the air: it experiences significant losses. This reduces concerns that unwanted persons could intercept the BCC signal.

There are two types of BCC connections. One is capacitive, which works similarly to touchscreens on smartphones and tablets and does not require direct electrode contact with the skin. The other is galvanic, which requires direct contact but is even safer, as even less signal leaks into the air, making it suitable for transmitting especially sensitive information.

In any case, most of the BCC signal propagates through the skin, so the majority of the electric field does not reach deeper tissues.

Is it safe?

The international engineering organization IEEE (Institute of Electrical and Electronics Engineers) has defined a safety standard for human interaction with electric, magnetic, and electromagnetic fields. The standard is IEEE C95.1-2019.

This standard specifies that the maximum current in contact with the human body at the frequencies used in the project must not exceed 16.7 milliamperes. BCC signal transmission requires significantly less current; for example, the current for the transmitter prototype in contact with the body is below one milliampere.

BCC uses low-voltage, variable-frequency signals. Compared to WiFi or mobile phone frequencies, BCC frequencies are low, and the transmitter power is small. BCC typically uses frequencies up to 30 megahertz (MHz). In comparison, WiFi and mobile networks operate around 3 gigahertz (GHz), roughly 100 times higher than BCC. These frequencies are also much, much lower than the electromagnetic spectrum frequencies at which ionizing radiation begins. Similarly, transmission powers differ: WiFi transmission power is 100 milliwatts (mW), while BCC signals use only about one milliwatt (mW).

Before research involving volunteers begins, the EDI ethics committee will review a detailed description and motivation. All volunteers will be provided with a consent form explaining the measurements performed on them. Following best scientific practices, volunteers can withdraw from the project at any time without giving a reason and can request that their data be deleted from the collected dataset. The study also plans to survey volunteers about the social acceptability of this technology.

The first experimental measurements to collect the dataset will be performed on the project participants themselves.

Does the project involve continuous use of volunteers for experiments?

No, volunteers are needed only for data collection, which requires only a few minutes of measurements per volunteer. Other project tasks, such as protocol development, will be carried out using computer simulations and experiments on artificial skin substrates.

Does the project involve implant installation?

No, implants are not part of this project. Future applications of this technology may include communication with implanted sensors, but this is not the project’s goal. If such projects are realized in the future, they will involve professional medical personnel and approval from the relevant ethics committees.

Where can I read more about the technology used?

A good popular science article on BCC technology is available in the December 2020 issue of IEEE Spectrum (PDF version available online).