FRET-based mobile molecular nanonetworks

Nanonetworks refer to a group of nano-sized machines with very basic operational capabilities communicating to each other in order to accomplish more complex tasks such as in-body drug delivery, or chemical defense. Realizing reliable and high-rate communication between these nanomachines is a fundamental problem for the practicality of these nanonetworks. Recently, we have proposed a molecular communication method based on Förster resonance energy transfer (FRET) which is a nonradiative excited state energy transfer phenomenon observed among fluorescent molecules, i.e., fluorophores. We have modeled the FRET-based communication channel considering the fluorophores as single-molecular immobile nanomachines, and shown its reliability at high rates, and practicality at the current stage of nanotechnology. In this study, we focus on network of mobile nanomachines communicating through FRET. We introduce two novel mobile molecular nanonetworks: FRET-based mobile molecular sensor/actor nanonetwork (FRET-MSAN) which is a distributed system of mobile fluorophores acting as sensor or actor node; and FRET-based mobile ad hoc molecular nanonetwork (FRET-MAMNET) which consists of fluorophore-based nanotransmitter, nanoreceivers and nanorelays. We model the single message propagation exploiting the SIR model of epidemics. We derive closed form expressions for the probability of the actor nodes to detect a message generated on the sensor nodes in FRET-MSAN, and for the average detection time of the transmitted message by the nanoreceivers in FRET-MAMNET. We numerically evaluate the performance of these networks in terms of reliability and transmission delay for varying number of nanonodes and varying size of nanomachines, as well as, for several FRET-related parameters.