A Novel Framework for Capacity Analysis of Diffusion-Based Molecular Communication Incorporating Chemical Reactions

In recent years, molecular communication (MC) is considered as a transformative paradigm in the communication theory and a promising solution to future nanoscale communication networks. In this article, a novel framework is introduced for diffusion-based MC and is shown how its capacity is impacted by the effects of chemical reactions which were neglected in the existing literature. Particularly, the chemical reactions corresponding to complex balanced chemical reaction networks are studied in this work. With an information-theoretic approach, the capacity is introduced where the effects of chemical reactions are taken into account. Then, the individual entropy derivations are addressed where the chemical reactions at the transmitter are considered with the chemical reaction network theory. Finally, the mutual information is derived based on these entropy derivations and the analytical capacity expressions are introduced accordingly. Numerical results exhibit the interactions between different parameters and show that the capacity actually decreases when the effects of chemical reactions are considered, implying that the capacity derived without chemical reactions was overestimated in previous studies. Consequently, the proposed framework analyzes the fundamental limits of diffusion-based MC and provides a more realistic capacity derivation comprising limitations imposed by chemical reactions, hence applicable to various more realistic MC scenarios.