Channel Modeling for Multi-Receiver Molecular Communication Systems

Molecular Communication via Diffusion (MCvD) is a prominent small-scale technology, which roots from the nature. With solid analytical foundations on channel response and advanced modulation techniques, molecular single-input-single-output (SISO) systems are one of the most studied molecular networks in the literature. However, the literature is yet to provide sufficient analytical channel modeling on molecular multiple-output systems with fully absorbing receivers, {one of the common applications in the area. In this paper, a channel model for molecular single-input-multiple-output (SIMO) systems is proposed for estimating the channel response of such systems. With the model's recursive nature, the closed-form solution of the channel response of molecular 2-Rx SIMO systems is analytically derived. A simplified model with lower complexity is also presented at a cost of slightly less accurate channel estimation. The models are extended to the molecular SIMO systems with more than two receivers. The performance of the methods are evaluated for several topologies with different parameters, and the accuracy of the model is verified by comparing to computer-simulated channel estimations in terms of quantitative error metrics such as root-mean-squared error. The performance of the simplified model is verified by the amount of deviation, indicating sufficient channel modeling performance with reduced computational power.Comment: 13 pages, 13 figures. Published in IEEE Transactions on Communication

Multi-Level Equilibrium Signaling for Molecular Communication

International audienceTwo key challenges in diffusion-based molecular communication are low data rates and accounting for the geometry of the fluid medium in the form of obstacles and the boundary. To reduce the need for the receiver to have knowledge of the geometry of the medium, binary equilibrium signaling has recently been proposed for molecular communication with a passive receiver in bounded channels. In this approach, reversible chemical reactions are introduced at the transmitter and the receiver in order for the system to converge to a known equilibrium state. This provides a means of designing simple detection rules that only depend on the transmitted signal and the volume of the bounded fluid medium. In this paper, we introduce multi-level equilibrium signaling, which allows for higher data rates via higher order modulation. We show that for a wide range of conditions, with appropriate receiver optimization, multi-level equilibrium signaling can outperform conventional concentration shift keying schemes. As such, our approach provides a basis to improve data rates in molecular communications without the need to increase the complexity of the system by exploiting techniques such as multiple information-carrying molecules