Molecular Communication Network MoleculeNet Deep Dive: A New Paradigm for Underwater Communication Using Chemical Molecules Instead of Electromagnetic Waves

On land, wireless communication is everywhere — Wi-Fi, 5G, Bluetooth — electromagnetic waves are our primary medium for transmitting information. But underwater, electromagnetic waves attenuate rapidly, acoustic communication has limited bandwidth and is easily disrupted by marine life. MoleculeNet, developed by Professor Chen Wei's team at the National University of Singapore's Department of Electrical and Computer Engineering, proposes a third option: encoding and transmitting information using chemical molecules.

Principle: From Neurons to Oceans

MoleculeNet draws inspiration from biological nervous systems. Signal transmission between neurons relies on the release and reception of chemical neurotransmitter molecules. Chen Wei's team scaled this principle to macroscopic dimensions: the transmitter precisely releases chemical molecule pulses of specific concentration through microfluidic chips, while the receiver's biochemical sensors detect concentration changes and decode them into binary data.

Each molecule pulse represents one bit — high concentration for 1, low concentration for 0. By controlling pulse timing and concentration gradients, the system achieves multi-bit encoding. In laboratory water tank tests, MoleculeNet achieved a transmission rate of 12 bits per second over a 10-meter distance, with a bit error rate below 0.1%.

Professor Chen stated: "This rate sounds low, but it is sufficient for marine environmental monitoring sensors. A temperature sensor only needs to transmit a few bytes of data per minute."

From Laboratory to Ocean

In May 2029, the team completed the first ocean field test off Sentosa Island in Singapore. Three MoleculeNet nodes were deployed at 15 meters depth, spaced 5 meters apart, successfully achieving 48 hours of continuous data transmission. The transmitted content included periodic readings of water temperature, salinity, and dissolved oxygen.

Compared to acoustic communication, MoleculeNet's advantage lies in its concealment — chemical signals cannot be detected by sonar and do not interfere with the acoustic environment of marine mammals. This gives it potential applications in military reconnaissance and marine ecological protection.

Limitations and Future

MoleculeNet's limitations are equally apparent. Chemical molecules diffuse much more slowly in water currents than electromagnetic waves and are easily affected by ocean currents and temperature gradients. The transmission distance is currently limited to 10 meters, and the rate is far below the thousands of bits per second of acoustic communication.

The team is developing a parallel transmission scheme based on multiple different molecules, which could theoretically increase the rate to 100 bits per second. Meanwhile, by optimizing molecule selection and release strategies, the transmission distance is expected to extend to 50 meters.

The European Marine Observation and Data Network (EMSO) has invited the MoleculeNet team to participate in evaluating communication solutions for Mediterranean deep-sea monitoring nodes. If the technology matures, molecular communication could become a supplementary communication method for underwater IoT, filling the gap between electromagnetic waves and acoustic waves.