Cognitive Molecular Communication in Cylindrical Anomalous-Diffusive Channel

Abstract

In this paper, an underlay cognitive molecular communication (MC) system with anomalous diffusion inside a blood-vessel like cylindrical channel is considered. We consider the presence of a primary and a secondary link in coexistence, with primary link having a higher priority for communication. To meet a certain quality of standard (QoS) at primary link, the interference due to the secondary is minimized by controlling the transmission at the secondary. The expressions for the concentration Green’s function (CGF) for anomalous diffusion and the number of molecules transmitted by the secondary transmitter are derived. The CGF is validated using the particle-based simulations. We analyze the channel performance in terms of probability of error, maximum achievable rate, receiver operating characteristics (ROC) and area under the curve (AUC). The decision threshold is optimized based on the log-likelihood ratio-test (LLRT) in order to minimize the probability of error. Furthermore, the effects of various parameters such as drift, diffusion, concentration degradation, channel radius and interference limit are analyzed. The derived expressions are validated through the Monte-Carlo simulations.