Reducing Dispersion in Molecular Communications by Placing Decelerators in the Propagation Channel

Abstract

In molecular communications, magnetic nanoparticles, which are injected into a pipe flow, are used as information carriers. Due to the parabolic shape of the velocity profile in laminar flow regimes, the speed of one particle depends on its radial position in the tube. This results in an unwanted extension of a particle pulse over the propagation time. Potential overlapping of subsequent pulses induces intersymbol interference. Only few research of the current state of the art reduces velocity dispersion directly within the propagation channel. To the best of the authors’ knowledge, this is the first paper that numerically investigates different passive obstacles which are placed directly in the channel for non-turbulent flow regimes to address the dispersion effects. These obstacles serve as decelerators, as they decelerate the fastest particles while at the same time accelerating slower particles. The results reveal that a passive decelerator can reduce the velocity dispersion in molecular communications and, thus, guarantee a more packetized pulse shortly behind the decelerator but also after some distance. Compared with different decelerators, an elliptical-shaped one showed the best results, as it inverts the velocity profile.