Multiple Ligands Channel Modeling for Finite-Receptor Reversible Reactive Receiver.

The study of molecular communication (MC) receivers with ligand receptors has attracted increasing interest. This receiver design is the most physically relevant, as the ligand-receptor interactions are common in biological systems, and thus suitable for MC devices and system architectures supported by biology. In this paper, we consider a ligand-receptor diffusion channel with several types of ligands, and they can react reversibly with the receptors. Under this scenario, competitions among different types of ligands for receptors may exist and largely affect the channel characteristics. In order to solve the above problems in channel modeling, we first utilize Fick’s law to obtain a mathematical model of this channel. And then we propose a Finite-Receptor Iterative (FRI) algorithm to achieve the channel impulse response (CIR), i.e. the expected number of receptors activated at the receiver surface by a particular type of ligand. It also reflects the competitions between different types of ligands for receptors by deriving the time-varying modified forward reaction rate for each type of ligand in each time slot. In addition, we analyse the competition mechanism of ligands for receptors and derive an interference element expression for describing it. We then present an approach to extend the analysis for a system with α ligands. Finally, we verify the accuracy of the analytical results by proposing a simulation framework for the considered environment.