Generalized Solution for the Demodulation of Reaction Shift Keying Signals in Molecular Communication Networks

Abstract

This paper considers a diffusion-based molecular communication system where the transmitter usesReaction Shift Keying (RSK) as the modulation scheme. We focus on the demodulation of RSK signal at the receiver. The receiver consists of a front-end molecular circuit and a back-end demodulator. The front-end molecular circuit is a set of chemical reactions consisting of multiple chemical species. The optimal demodulator computes the posteriori probability of the transmitted symbols given the history of the observation. The derivation of the optimal demodulator requires the solution to a specific Bayesian filtering problem. The solution to this Bayesian filtering problem had been derived for a few specific molecular circuits and specific choice(s) of observed chemical species. The derivation of such solution is also lengthy. The key contribution of this paper is to present a general solution to this Bayesian filtering problem which can be applied to any molecular circuit and any choice of observed species.

Using Spatial Partitioning to Reduce the Bit Error Rate of Diffusion-Based Molecular Communications

“…The front-end block consists of a molecular circuit, which is another name for a set of chemical reactions. In [15], the front-end block is assumed to be a reversible ligand-receptor binding while in [16], the front-end block can be any molecular circuit. For example, the following molecular circuit is considered in [42]:…”

“…This is an optimal Bayesian filtering problem. The structure of this filtering problem is identical to the one considered in [16]. In [16], we consider a filtering problem where the state vector evolves according to a CTMP.…”

“…For both configurations, we derive the maximum-a-posteriori (MAP) demodulator by leveraging our earlier work on designing demodulators for diffusion-based molecular communications using a Markovian approach [15] [16]. This paper also removes a limitation of our earlier work in [15] [16] where the receiver is assumed to be a small cubic volume called a voxel. In this paper, we assume that the receiver consists of multiple voxels and the union of these voxels define the shape of the receiver.…”

“…This method of modelling a 3-dimensional volume is similar to that in finite difference method. In this paper, we extend the method of demodulator design in [15] [16] to the multi-voxel case.…”

“…Section II discusses the related work. In Section III we present the background and a summary of our previous work in [15] [16]. Section IV presents the MAP demodulator for the partitioned and mixed configurations.…”