Adaptive Molecular Communication Receivers with Tunable Ligand-Receptor Interactions

Abstract: Molecular Communications (MC) underpins signaling in biological systems, enabling information transfer through biochemical molecules. The prospect of engineering this natural communication mechanism has inspired the Internet of Bio-Nano Things (IoBNT) applications, which rely on heterogeneous collaborative networks of natural and engineered biological devices, as well as artificial micro/nanomachines. A key attribute of natural MC systems is their adaptability, ensuring accurate information transmission in dynamic, time-varying biochemical environments. Therefore, integrating biological adaptation techniques into artificial MC networks, which are expected to operate in various biochemical environments, such as inside human body, is essential for robust and biocompatible IoBNT applications. This study explores the design of bio-inspired adaptive MC receivers capable of tuning their response functions for maintaining optimal detection performance in scenarios with time-varying received signals. The proposed receiver architectures are based on ligand-receptor interactions, with adaptivity achieved by modifying the sigmoidal-shaped ligand-receptor response curve in response to fluctuations in received signal statistics. The performance of these adaptive receivers is evaluated across a range of MC scenarios, including those with stochastic background interference, inter-symbol interference (ISI), and degrading enzymes, which involve time-varying scaling or shifting of received signals. Numerical results demonstrate the significant improvement in detection performance provided by adaptive receivers in dynamic MC scenarios.