Testbeds play an essential role in the development of real-life molecular communication applications and experimental validation of communication channel models. Although some testbed concepts have been published in recent years, very few setups are inherently suitable for biomedical applications. Furthermore, systematic experimental data of a wide parameter field for molecular communication is scarce and often difficult to generate. In this work, a biocompatible testbed for molecular communication with magnetic nanoparticles is used to investigate a series of transmission channel parameters. The observed results are discussed in the context of a laminar flow channel. All experimental data regarding the parameter studies as well as an additional data set for a large binary transmission sequence is provided as a supplement to this publication. The data is available on a public server to allow for further use by other researchers.

Testbeds play an essential role in the development of real-life molecular communication applications and experimental validation of communication channel models. Although some testbed concepts have been published in recent years, very few setups are inherently suitable for biomedical applications. Furthermore, systematic experimental data for molecular communication is scarce and often difficult to generate. In this work, a biocompatible testbed for molecular communication with magnetic nanoparticles is used to investigate a series of transmission channel parameters. The observed results are discussed in the context of a laminar flow channel. All experimental data regarding the parameter studies as well as an additional data set for a large binary transmission sequence is provided as a supplement to this publication, enabling further use by other researchers.

Although the concept of engineered molecular communication has been around for quite some time, practical approaches with truly biocompatible setups are still scarce. However, molecular communication has a large potential in future medical applications and may be a solution to size constraints of antenna-based transmission systems. In this work, we therefore present a testbed using biocompatible magnetic nanoparticles. Based on previous work, all testbed components have been improved regarding performance and size, making a large step forward regarding miniaturisation and a data transmission approach. In addition, a setup for localised two-dimensional sensing of magnetic nanoparticles is presented. All improvements are evaluated individually and combined to achieve a net data rate of more than $\mathrm {6~ \text {bit} / \text {s}}$ , significantly higher than any other comparable biocompatible setup.

Testbeds play an essential role in the development of real-life molecular communication applications and experimental validation of communication channel models. Although some testbed concepts have been published in recent years, very few setups are inherently suitable for biomedical applications. Furthermore, systematic experimental data of a wide parameter field for molecular communication is scarce and often difficult to generate. In this work, a biocompatible testbed for molecular communication with magnetic nanoparticles is used to investigate a series of transmission channel parameters. The observed results are discussed in the context of a laminar flow channel. All experimental data regarding the parameter studies as well as an additional data set for a large binary transmission sequence is provided as a supplement to this publication. The data is available on a public server to allow for further use by other researchers.

Abstract Molecular communication is a novel approach for data transmission between miniaturised devices, especially in contexts where electrical signals are to be avoided. The communication is based on sending molecules (or other particles) at nanoscale through a typically fluid channel instead of the “classical” approach of sending electrons over a wire. Molecular communication devices have a large potential in future medical applications as they offer an alternative to antenna-based transmission systems that may not be applicable due to size, temperature, or radiation constraints. The communication is achieved by transforming a digital signal into concentrations of molecules that represent the signal. These molecules are then detected at the other end of the communication channel and transformed back into a digital signal. Accurately modeling the transmission channel is often not possible which may be due to a lack of data or time-varying parameters of the channel (e.g., the movements of a person wearing a medical device). This makes the process of demodulating the signal (i.e., signal classification) very difficult. Many approaches for demodulation have been discussed in the literature with one particular approach having tremendous success – artificial neural networks. These artificial networks imitate the decision process in the human brain and are capable of reliably classifying even rather noisy input data. Training such a network relies on a large set of training data. As molecular communication as a technology is still in its early development phase, this data is not always readily available. In this paper, we discuss neural network-based demodulation approaches relying on synthetic simulation data based on theoretical channel models as well as works that base their network on actual measurements produced by a prototype test bed. In this work, we give a general overview over the field molecular communication, discuss the challenges in the demodulations process of transmitted signals, and present approaches to these challenges that are based on artificial neural networks.

In this work, we present a novel portable, flexible and easy-to-use experimental setup for investigating salinity-based information transmission in microfluidic channels. At the receiver, the different salinity-levels are detected by a customized electronic circuit, which measures electrical conductivity via electrodes in the microfluidic channel. We provide a detailed description of the setup, including the microfluidic chip fabrication. Moreover, we develop a rigorous mathematical model of each testbed component and an end-to-end model of the system, which we have verified through experiments. Finally, we analyzed the error performance of the setup using optimum and sub-optimum detection algorithms, such as the Viterbi algorithm and threshold detection.

Molecular communication presents a new approach for data transmission between miniaturised devices, especially in the context of medical applications. A communication link is established using molecules, or other particles in the nanoscale, to modulate information. Due to a lack of data or changing physical parameters, the information channel often cannot be modelled accurately. Deep Learning provides a solution to receive a transmitted data sequence without the need for an analytical description of the channel. We present a proof-of-concept for the application of a Convolutional Neural Network to demodulate a signal using concentration shift keying. The demodulation predictor is evaluated with experimental data from a testbed using magnetic nanoparticles in an active background flow in comparison to a conventional learning approach with Linear Discriminant Analysis. The new demodulator shows a better performance for higher symbol rates than the conventional approach. Using a modulation alphabet with 8 symbols a data rate of more than 5.5 bit s−1 can be achieved. The constructed neural network can be trained in under two minutes and can easily be adapted to changing transmission parameters.

Testbeds enable experimental investigation of molecular communication concepts and transmission schemes. One approach to biocompatible molecular communication, implemented in a testbed, is the use of magnetic nanoparticles as information carriers. These nanoparticles can be detected based on their high susceptibility using an inductive sensor. So far, a wire-wound sensing coil, that requires manual manufacturing and is difficult to install for a real-life transmission channel, was used. Here, we propose the use of planar coils. To this end, a selection of commercially available coils are evaluated in comparison to a conventional wire-wound coil as reference. A planar coil is then successfully used to detect magnetic nanoparticles in the context of the molecular communication testbed. The contribution is concluded with an outlook on future improvements made possible through the application of planar sensing coils.

Monitoring and control systems, including spatially distributed devices, often require simultaneous responses to control commands. Especially when timing is crucial a synchronized connection between all devices is necessary to minimize differences in response time. This paper introduces a method which uses Bluetooth periodic advertising to establish a wireless synchronized multicast to simultaneously control devices. Results of time difference measurements between two devices, reacting on control commands received by the same periodic advertising packet, are introduced and discussed using large scale experimental data. Device configurations, where an impact on timing was experienced, are presented. Time difference values with a low maximum delay of 11 µs were achieved.

Molecular Communication provides a solution for scenarios where conventional technologies for data transmission are not feasible due to energy or size constraints. The development and characterisation of sensor devices for information particles as receivers is an essential step to realising Molecular Communication setups. In this work we will present a new device for sensing of magnetic nanoparticles using a capacitor to detect changes in permittivity. The sensor was evaluated regarding sensitivity and a data transmission scenario in a testbed and compared to an inductive sensor. The new sensor device has a significantly higher sensitivity than the reference sensor, allowing for the use of less information particles when transmitting data. However, the impulse response is wider as magnetic nanoparticles are held in the electromagnetic field of the receiver’s capacitor.

This manuscript was published at 08.10.2021 by the IEEE Transactions on Magnetics. Regarding Mr. Sivo's Email, the accepted version of the manuscript is now uploaded which also includes the corresponding DOI.

In the field of molecular communication, molecules or other particles in the nanoscale are used to transmit information. This rather new communication paradigm has a large application potential, ranging from medicine to industrial systems. As testbeds are essential for evaluating the capabilities of this new form of communication, we improve an existing water-based testbed to achieve parallel data transmission within one communication channel in this work. To this end, two different information carriers, superparamagnetic iron oxide nanoparticles and fluorescent particles, are used to simultaneously transmit independent data streams. A detection system for fluorescent particles was specifically developed for the fluid molecular communication testbed. Using parallel data transmission in the modified testbed the channel capacity was nearly doubled in comparison to a transmission using only a single type of information particles.

This manuscript was submitted at 29.12.2020 to the IEEE Transactions on Biomedical Engineering.

Droplet-based microfluidics show a large potential for lab-on-chip applications and new data transmission scenarios. Microfluidic chips contain channels in the submillimeter range allowing for flow of droplets. In a previous contribution, a new sensor design for droplet size and colour detection, consisting of an infrared and a colour sensor, was presented and a first proof-of-concept was shown. In this work, an in-depth analysis of both concepts is presented. In particular, we show that a high precision can be achieved when using the sensor to measure droplet sizes while using video processing software as reference. Furthermore, a colour alphabet consisting of 126 individual values is transmitted and detected using a machine learning model. The high specificity of achieved colour measurement allows both for colour coded data transmission scenarios and the analysis of colour reagents in lab-on-chip applications.

Molecular communication in pipe networks is a novel technique for wireless data exchange. Simulating such networks accurately is difficult because of the complexity of fluid dynamics at centimeter scales, which existing molecular communication simulators do not model. The new simulator we present combines computational fluid dynamics simulation and particle movement predictions. It is optimized to be computationally efficient while offering a high degree of adaptability to complex fluid flows in larger pipe networks. We validate it by comparing the simulation with experimental results obtained in a real-world testbed.

Droplet-based microfluidic systems are a promising platform for lab-on-a-chip (LoC) applications. These systems can also be used to enhance LoC applications with integrated droplet control information or for data transmission scenarios in the context of molecular communication. For both use-cases the detection and characterisation of droplets in small microfluidic channels is crucial. So far, only complex lab setups with restricted capabilities have been presented as detection devices. We present a new low-cost and portable droplet detector. The device is used to confidently distinguish between individual droplets in a droplet-based microfluidic system. Using on-off keying a 16-bit sequence is successfully transmitted for the first time with such a setup. Furthermore, the devices capabilities to characterise droplets regarding colour and size are demonstrated. Such an application of a spectral sensor in a microfluidic system presents new possibilities, such as colour-coded data transmission or analysis of droplet content.

Molecular communication uses molecules or other nanoscale particles to transmit data in scenarios where conventional communication techniques are not feasible. In previous work a testbed using superparamagnetic iron oxide nanoparticles (SPIONs) as information carriers in a fluid transmission channel with constant background flow was proposed. The SPIONs are detected at a receiver as change of a coils inductance. We now improve the testbed by using a piezoelectric micropump as transmitter, making amplitude modulation (AM) with di?erent injection volumes possible. Machine learning is employed at the receiver to di?erentiate between six di?erent amplitude levels and grey code is used to reduce bit errors. With AM and the designed coding scheme, the achievable e?ective data rate was doubled to 4.45 bit/s.

Molecular communication (MC) denotes information transmission by use of molecules and nanosized particles. For the realization of testbeds, superparamagnetic iron oxide nanoparticles (SPIONs) in duct flow have recently been proposed. Here, an experimental setup is provided to direct these particles at a branching of a tube into a specific direction by use of magnetic fields. For that purpose, gold-coated SPIONs suspended in water at constant flow rate are considered at a Y-shaped connector of tubes. The particles are attracted by use of a custom-made electromagnet, while change of particle concentration in either of the branches is measured by a commercial susceptometer. The approach is evaluated for different flow rates and with the electromagnet both at a fixed position and moving along the tube. Exemplary measurements show that an information transmission is feasible in both approaches and with all tested flow rates. The feasibility study hence shows that particle steering by use of magnetic fields is a viable approach, which is even robust against flow rate variations. It can thus be used in MC to address different transmission channels as well as to realize differential signal transmission. Furthermore, it might help to improve magnetic drug targeting in future applications.

Superparamagnetic iron oxide nanoparticles (SPIONs) have recently been introduced as information carriers in a testbed for molecular communication (MC) in duct flow. Here, a new receiver for this testbed is presented, based on the concept of a bridge circuit. The capability for a reliable transmission using the testbed and detection of the proposed receiver was evaluated by sending a text message and a 80 bit random sequence at a bit rate of 1/s, which resulted in a bit error rate of 0 %. Furthermore, the sensitivity of the device was assessed by a dilution series, which gave a limit for the detectability of peaks between 0.1 to 0.5 mg/mL. Compared to the commercial susceptometer that was previously used as receiver, the new detector provides an increased sampling rate of 100 samples/s and flexibility in the dimensions of the propagation channel. Furthermore, it allows to implement both single-ended and differential signaling in SPION-bases MC testbeds.