A General Analytical Approximation to Impulse Response of 3-D Microfluidic Channels in Molecular Communication

In this paper, the impulse response for a 3-D microfluidic channel in the presence of Poiseuille flow is obtained by solving the diffusion equation in radial coordinates. Using the radial distribution, the axial distribution is then approximated accordingly. Since Poiseuille flow velocity changes with radial position, molecules have different axial properties for different radial distributions. We, therefore, present a piecewise function for the axial distribution of the molecules in the channel considering this radial distribution. Finally, we lay evidence for our theoretical derivations for impulse response of the microfluidic channel and radial distribution of molecules through comparing them using various Monte Carlo simulations.Comment: The manuscript is submitted to IEEE: Transactions on Nanobioscienc

Diffusive molecular communication in a biological spherical environment with partially absorbing boundary

Diffusive molecular communication (DMC) is envisioned as a promising approach to help realize healthcare applications within bounded biological environments. In this paper, a DMC system within a biological spherical environment (BSE) is considered, inspired by bounded biological sphere-like structures throughout the body. As a biological environment, it is assumed that the inner surface of the sphere’s boundary is fully covered by biological receptors that may irreversibly react with hitting molecules. Moreover, information molecules diffusing in the sphere may undergo a degradation reaction and be transformed to another molecule type. Concentration Green’s function (CGF) of diffusion inside this environment is analytically obtained in terms of a convergent infinite series. By employing the obtained CGF, the information channel between transmitter and transparent receiver of DMC in this environment is characterized. Interestingly, it is revealed that the information channel is reciprocal, i.e., interchanging the position of receiver and transmitter does not change the information channel. Results indicate that the conventional simplifying assumption that the environment is unbounded may lead to an inaccurate characterization in such biological environments

Macro-Scale Molecular Communications

The use of electromagnetic (EM) waves to transmit information has allowed our society to collaborate and share information on a scale that was unimaginable just a few decades ago. But as with any technology, there are areas where EM-based communications do not function well. For example, underwater and underground communications where EM waves experience high attenuation. This limitation has generated interest in an alternative mode of information transmission, molecular communications. In this thesis, after giving a survey of micro- and macro-scale molecular communications, the two most important aspects of molecular communications are identified: macroscale molecular communications and the experimental analysis of molecular communications. Molecular communication has been dominated so far by interest in the nano-scale, where the application focus is on drug-delivery and DNA communications, etc. Studies in the macro-scale are relatively rare compared to nano- and micro-scale research. This thesis looks closely at macro-scale molecular communication and attempts to improve our understanding of this novel communication paradigm. To achieve this, a mathematical model was developed, based on the advective-diffusion equation (ADE). The model was compared with experimental results, and showed a strong correlation. In addition, a model was developed to simulate molecular communication in both 1D and 3D environments. To generate the modulated chemicals and transmit them in the environment, an inhouse- built odour generator was used, and to detect the chemicals in the environment a mass spectrometer (MS) with a quadrupole mass analyser (QMA) was employed. Mass spectrometers have the ability to distinguish multiple chemicals in the environment concurrently, making them ideal detectors for use in molecular communications. Based on the experimental setup, various aspects of the communication paradigm are investigated in the three main sections. The first section focuses on the fundamental parameters that govern the propagation of molecules in a flow. The second section delves into the communication properties of this new form of information transfer. The final section studies aspects of simultaneous multiple-chemical transmission. Based on this multiple-chemical transmission, modulation methods are developed that exploit this new approach for use in molecular communications