On the Physical Design of Receiver for Molecular Communications

Molecular communications, where molecules are used to encode, transmit, and receive information, is a promising means of enabling the coordination of nanoscale devices. The paradigm has been extensively studied from various aspects, including channel modeling and noise analysis. Comparatively little attention has been given to the physical design of molecular receiver and transmitter, envisioning biological synthetic cells with intrinsic molecular reception and transmission abilities as the future nanomachines. However, this assumption leads to a discrepancy between the envisaged applications requiring complex communication interfaces and protocols, and the very limited computational capacities of the envisioned biological nanomachines. In this paper, we examine the feasibility of designing a molecular receiver, in a physical domain other than synthetic biology, meeting the basic requirements of nanonetwork applications. We first review the state-of-the-art biosensing approaches to determine whether they can inspire a receiver design. We reveal that nanoscale field effect transistor (FET)-based electrical biosensor is a particularly useful starting point towards designing a molecular receiver. Focusing on FET-based molecular receivers with a conceptual approach, we provide a guideline elaborating on their operation principles, performance metrics, and design parameters. We then develop a deterministic model for signal flow in silicon nanowire (SiNW) FET-based molecular receiver, and investigate its sensitivity for varying system parameters. Lastly, we discuss the practical challenges of implementing the receiver, and present the future research avenues from a communication theoretical perspective.