Chemical Reactions-based Detection Mechanism for Molecular Communications

TL;DR

This paper proposes an indirect detection mechanism for molecular communications using chemical reactions with molecular probes, offering improved detection performance over direct methods by optimizing probe parameters and decision thresholds.

Contribution

It introduces a novel chemical reaction-based detection method, models the reaction-diffusion system with an efficient iterative algorithm, and demonstrates improved bit error rate performance.

Findings

Product and signaling molecule concentrations share a single peak and long tail.

Probe parameters can control the peak and tail of the product concentration.

Optimizing the decision threshold enhances detection accuracy.

Abstract

In molecular communications, the direct detection of signaling molecules may be challenging due to a lack of suitable sensors and interference in the environment. Motivated by research in molecular biology, we investigate an indirect detection mechanism using chemical reactions between the signaling molecules and a molecular probe to produce an easy-to-measure product at the receiver. We consider two implementations of the proposed detection mechanism, i.e., unrestricted probe movement and probes restricted to a volume around the receiver. The reaction-diffusion equations describing the concentrations of the reactant and product molecules in the system are non-linear and coupled, and cannot be solved in closed form. Therefore, we develop an efficient iterative algorithm by discretizing the time variable and solving for the space variables of the equations in each time step. Our results show that the concentrations of the product molecules and the signalling molecules share a similar characteristic over time, i.e., a single peak and a long tail. The peak and tail values of the product molecule concentration can be controlled by choosing probes with suitable parameters. By carefully choosing the molecular probe and optimizing the decision threshold, the BER can be improved significantly and outperform that of a direct detection system.