Molecular Communication Systems in Tubes with Non-Newtonian Fluid Flows

Blood vessels are essential communication channels for in-vivo molecular communication (MC) systems. Typically, MC researchers model vascular channels as cylindrical tubes with Newtonian fluid flows. However, blood exhibits as a non-Newtonian fluid at a low shear rate. The characteristics of flow in a non-Newtonian fluid differ from those in a Newtonian fluid, resulting in the transport of information molecules (IMs) in the blood being different from that in Newtonian fluids. To analyze the influences of non-Newtonian fluid flows on the performance of MC systems, we develop an MC system in a tube with a non-Newtonian fluid flow in this paper. We obtain the distribution of molecules by deriving the asymptotic equation for the cross-sectional averaged concentration of IMs and formulate expressions for the first passage time probability (FPTP) and first passage time probability density function (FPTPDF). The derived expressions are validated through particle-based simulations. Moreover, the impacts of the non-Newtonian fluids on MC systems are examined in terms of the average bit error rate (BER) and the data transfer rate. Simulation results are presented to verify the theoretical results.