Our paper "Spheroidal Molecular Communication via Diffusion: Signaling Between Homogeneous Cell Aggregates" (arXiv link) has been accepted to appear in IEEE Transactions on Molecular, Biological, and Multi-Scale Communications. We model two spheroids as transmitter and receiver in a diffusion-based molecular communication system. Both spheroids are modeled as spheres whose porous features are approximated with a lower diffusion coefficient than that of the surrounding fluid medium. We derive the end-to-end channel impulse response and characterize the corresponding communications performance.

This paper is an output of the SIMBA project and is the first journal paper of Mitra Rezaei's PhD. It was also co-authored with Hamidreza Arjmandi from our group, in addition to Mohamad Zoofaghari (Yazd University, Iran) and our SIMBA project collaborators at AstraZeneca Sweden (Kajsa Kanebratt, Liisa Vilen, David Janzen, and Peter Gennemark).

Our paper "Membrane Fusion-Based Transmitter Design for Static and Diffusive Mobile Molecular Communication Systems" (alternative arXiv link) was accepted for publication in IEEE Transactions on Communications. This paper considers a novel molecular communication system where the transmitter is a membrane-bound sphere and vesicles bind to and fuse with the sphere in order to release molecules into the propagation environment. Such a system is more reflective of cellular signalling than the point- or volume-based transmitters that are usually modelled. We derive the resulting molecule release probability and the corresponding impact on what is observed at an absorbing receiver. Our simulation results show how the hitting probability at the receiver is impacted by slow vesicle diffusion or a low membrane fusion probability. The paper was co-authored with Xinyu Huang (Australian National University), Yuting Fang (Melbourne, Australia), and Nan Yang (Australian National University).

Our paper "A Survey of Molecular Communication in Cell Biology: Establishing a New Hierarchy for Interdisciplinary Applications" (open access DOI) was accepted for publication in IEEE Communications Surveys & Tutorials. This paper bridges the gap between life sciences and communications engineering to promote the application of molecular communication as a methodology for applications that require communication between cells and other microscale devices. To do so, we propose a novel communication hierarchy for molecular communication signalling in cell biology. We map biological phenomena, research contributions, and open problems to the hierarchy. We also apply the hierarchy to case studies on quorum sensing, neuronal signalling, and communication via DNA. This paper was co-authored with Apostolos Almpanis from our group, in addition to Dadi Bi and Yansha Deng (King's College London), and Robert Schober (FAU, Germany).

Our paper "Characterization of Cooperators in Quorum Sensing with 2D Molecular Signal Analysis" (link to arXiv version; here is the DOI) was accepted for publication in IEEE Transactions on Communications. This paper models quorum sensing by a community of bacteria. Each bacterium makes a single decision whether to cooperate based on the quorum sensing signal observed due to the aggregate bacterial population. We apply stochastic geometry to derive the quorum sensing channel statistics and the distribution of the number of bacteria that choose to cooperate. Derivations are verified with particle-based simulations. The paper was co-authored with Yuting Fang (Melbourne, Australia), Andrew W. Eckford (York, Canada), Nan Yang (Australian National University), and Jing Guo (Beijing Institute of Technology). An early version was presented at IEEE GLOBECOM 2019 under the title "Expected Density of Cooperative Bacteria in a 2D Quorum Sensing Based Molecular Communication System".

Our paper "Modeling Interference-Free Neuron Spikes with Optogenetic Stimulation" (link to arXiv version; here is the DOI) was accepted for publication in IEEE Transactions on Molecular, Biological and Multi-Scale Communications. This paper tries to predict the charging and recovery times of neurons that follow the Izhikevich model and that are stimulated with an external current (such as by a light source in the case of optogenetics). We measure the sensitivity of the charging and recovery times as functions of the stimulation current and the Izhikevich model parameters. We also measure the distortion when we try to generate sequences of action potential spikes at frequencies that are too high for a neuron membrane to return to its resting potential before it is stimulated again. The paper was co-authored with Shayan Monabbati (Case Western, USA), Dimitrios Makrakis (uOttawa, Canada), and Andrew W. Eckford (York, Canada). An early version was presented at IEEE ICC 2018 under the title "Timing Control of Single Neuron Spikes with Optogenetic Stimulation".

The paper "Molecular Information Delivery in Porous Media" (link to arXiv version; here is the DOI) was accepted for publication in IEEE Transactions on Molecular, Biological, and Multi-Scale Communications. We perform the first study of using a porous material as a diffusive communication channel. With the help of statistical breakthrough curves, we compare the characteristics of communication in a porous channel with that of the more familiar free space diffusion channel. One key difference is that increasing the Peclet number in a porous channel can increase the size of the tail of the channel impulse response, whereas this would decrease the size of the channel impulse response tail in the free space case. This paper was co-authored with Yuting Fang (ANU, Australia), Weisi Guo (Warwick), Matteo Icardi (Nottingham), and Nan Yang (ANU, Australia).

The paper "Diffusive Molecular Communication in a Biological Spherical Environment with Partially Absorbing Boundary" (link to arXiv version; here is the DOI) was accepted for publication in IEEE Transactions on Communications. We derive the diffusive channel response for a transmitter and receiver that are arbitrarily placed within a partially absorbing spherical shell. This paper was co-authored with Hamidreza Arjmandi and Mohammad Zoofaghari (both at Yazd University, Iran).

The paper "A Novel A Priori Simulation Algorithm for Absorbing Receivers in Diffusion-Based Molecular Communication Systems" (link to arXiv version; here is the DOI) was accepted for publication in IEEE Transactions on NanoBioscience. We propose a Monte Carlo type approach to efficiently simulate surface absorption in microscopic particle-based simulations. The algorithm is shown to be very accurate when simulating with large time steps. This paper was co-authored with Yiran Wang and Nan Yang (both at ANU, Australia). An implementation of this algorithm is included in the AcCoRD simulator (Actor-based Communication via Reaction-Diffusion).

The paper "Channel Modeling for Diffusive Molecular Communication - A Tutorial Review" (link to arXiv version; here is the DOI) was accepted for publication in Proceedings of the IEEE. We do an extensive review of the end-to-end communication channel models that are available for diffusive molecular communication systems, as well discuss simulation methods and experimental testbeds. It should be a helpful resource for anyone interested in working in this area, whether you are new to the field or an experienced member. This paper was co-authored with colleagues at FAU (Germany): Vahid Jamali, Arman Ahmadzadeh, Wayan Wicke, and Robert Schober.

The paper "Symbol-by-Symbol Maximum Likelihood Detection for Cooperative Molecular Communication" (link to arXiv version; here is the DOI) was accepted for publication in IEEE Transactions on Communications. We propose different methods of maximum-likelihood-based detection when a fusion centre combines observations of diffusing molecules by a collection of receivers. This paper was co-authored with Yuting Fang (ANU, Australia), Nan Yang (ANU, Australia), Andrew W. Eckford (York, Canada), and Rodney A. Kennedy (ANU, Australia).