Design and Analysis of Wireless Communication Systems Using Diffusion-Based Molecular Communication Among Bacteria

Abstract

The design of biologically-inspired wireless communication systems using bacteria as the basic element of the system is initially motivated by a phenomenon called Quorum Sensing. Due to high randomness in the individual behavior of a bacterium, reliable communication between two bacteria is almost impossible. Therefore, we have recently proposed that a population of bacteria in a cluster is considered as a bio node in the network capable of molecular transmission and reception. This proposition enables us to form a reliable bio node out of many unreliable bacteria. In this paper, we study the communication between two nodes in such a network where information is encoded in the concentration of molecules by the transmitter. The molecules produced by the bacteria in the transmitter node propagate through the diffusion channel. Then, the concentration of molecules is sensed by the bacteria population in the receiver node which would decode the information and output light or fluorescent as a result. The uncertainty in the communication is caused by all three components of communication, i.e., transmission, propagation and reception. We study the theoretical limits of the information transfer rate in the presence of such uncertainties. Finally, we consider Mary signaling schemes and study their achievable rates and corresponding error probabilities.

Performance of SW-ARQ in bacterial quorum communications

“…In addition, the delay in the communication process can be fairly large due to biological actions such as transcription and translation. Hence, to achieve reliability of the communication system, here, the communications model between two populations of bacteria which is proposed in [4] is taken into consideration. In this model, a cluster of bacteria trapped in a chamber is considered as a node.…”

“…the embedding of the information is by alteration of the concentration of the molecules and its transmission relies on diffusion. The output of the receiver node, in the form of luminescence, is measured in steadystate to estimate the concentration of signalling molecules at the vicinity of the node, and hence decode the transmitted information [4]. In this proposed model, both the transmitter and receiver nodes contain N bacteria, specifically Vibrio fischeri, which is a species of bioluminescent bacterium.…”

“…Fig. 1 [4] illustrates the process with the structure of a bacterium used in such a node shown in Fig. 1 (a).…”

“…They communicate with each other using signalling molecules to perform complex tasks [3] such as light production and attacking suitable hosts. In particular, if the concentration of molecular signals in the medium exceeds a certain threshold, an individual bacterium in a population releases more molecules into the environment [4], which will in turn increase the density of signalling molecules over time. This produces what can be considered as a positive feedback process.…”

“…Thus, the local density of bacteria can be measured by sensing the concentration of molecules present and bacteria perform tasks when the concentration exceeds a certain threshold. The output of the QS mechanism can be in various forms and one example is the production of Green Fluorescent Protein (GFP) [4]. A well-studied bacteria species, Vibrio fischeri, which is most famous for its bioluminescence and has been used to study toxicity of aquatic environments, has been employed to investigate the bacterial communication network in this paper.…”