Fundamentals of Concentration-encoded Molecular Communication

Abstract

Molecular communication (MC) is a new bio-inspired communication paradigm towards realizing the communication and networking at the nanoscale to microscale dimensions among a vast number of engineered natural and/or artificial nanomachines communicating with each other to form a nanonetwork. In this thesis, we investigate a concentration-encoded molecular communication (CEMC) system where the transmitting nanomachine (TN) and the receiving nanomachine (RN) communicate with a single type of information molecules by modulating the transmission rate of information molecules at the TN. The information molecules undergo ideal (i.e. free) diffusion in three dimensions and become available to the RN that observes the concentration of the received molecules at its receptors and thus decodes the message. Our research shows that it is possible to realize complex modulation methods, combat the intersymbol interference (ISI), determine the effective communication ranges based on available signal concentration, develop signal detection schemes, and apply simple channel codes in a CEMC system. It has been found that the performance of the CEMC system is influenced by communication ranges, transmission data rates, ISI, and detection schemes. It is possible to sense the concentration signal intensity and develop optimum receiver structures that can detect the transmitted symbols at the RN. It is also possible to develop optimum signal detection schemes based on the interactions between the information molecules and the receptors using stochastic chemical kinetics (SCK) of the reaction events. Applying simple channel codes at the TN shows that it is possible to increase effective communication range in the CEMC system, however, this increases the complexity of the RN in implementing the detection circuitry. Finally, potential applications of CEMC would be in materializing CEMC-based molecular nanonetworks for emerging areas, e.g. in cancer detection and treatment, targeted drug delivery, and environmental protection and pollution control.