A Markovian Approach to the Optimal Demodulation of Diffusion-based Molecular Communication Networks

TL;DR

This paper develops an optimal demodulation method for diffusion-based molecular communication networks by modeling the entire process as a continuous-time Markov process and applying Bayesian filtering for signal detection.

Contribution

It introduces a comprehensive Markovian model that incorporates transmitter reactions, diffusion, and receptor interactions, and derives an optimal demodulator using Bayesian filtering.

Findings

The optimal demodulator effectively captures the stochastic noise in the system.

Numerical examples demonstrate the demodulator's performance and properties.

The approach provides a theoretical foundation for improved molecular communication detection.

Abstract

In a diffusion-based molecular communication network, transmitters and receivers communicate by using signalling molecules (or ligands) in a fluid medium. This paper assumes that the transmitter uses different chemical reactions to generate different emission patterns of signalling molecules to represent different transmission symbols, and the receiver consists of receptors. When the signalling molecules arrive at the receiver, they may react with the receptors to form ligand-receptor complexes. Our goal is to study the demodulation in this setup assuming that the transmitter and receiver are synchronised. We derive an optimal demodulator using the continuous history of the number of complexes at the receiver as the input to the demodulator. We do that by first deriving a communication model which includes the chemical reactions in the transmitter, diffusion in the transmission medium and the ligand-receptor process in the receiver. This model, which takes the form of a continuous-time Markov process, captures the noise in the receiver signal due to the stochastic nature of chemical reactions and diffusion. We then adopt a maximum a posterior framework and use Bayesian filtering to derive the optimal demodulator. We use numerical examples to illustrate the properties of this optimal demodulator.