An M-Ary Concentration-Shift Keying With Common Detection Thresholds for Multitransmitter Molecular Communication

Abstract

Concentration shift keying (CSK) is a widely studied modulation technique for molecular communication-based nanonetworks, which is a key enabler for the Internet of Bio-NanoThings (IoBNT). Existing CSK methods, while offering optimal error performance, suffer from increased operational complexity that scales poorly as the number of transmitters, K, grows. In this study, a novel M-ary CSK method is proposed: CSK with common detection thresholds (CSK-CT). CSK-CT uses common thresholds, set sufficiently low to guarantee the reliable detection of symbols from all transmitters, regardless of distance. Closed-form expressions are derived to obtain the common thresholds and release concentrations. To further enhance error performance, the release concentration is optimized using a scaling exponent that also optimizes the common thresholds. The performance of CSK-CT is evaluated against the benchmark CSK across various K and M values. CSK-CT has an error probability between 10 −7 and 10 −4 , which is a substantial improvement from that of the benchmark CSK (from 10 −4 to 10 −3 ). In terms of complexity, CSK-CT is O n and does not scale with K but M (M K), whereas the benchmark is O n 2 . Furthermore, CSK-CT can mitigate inter-symbol interference (ISI), although this facet merits further investigation. Owing to its low error rates, improved scalability, reduced complexity, and potential ISI mitigation features, CSK-CT is particularly advantageous for IoBNT applications focused on data gathering. Its effectiveness is especially notable in scenarios where a computationally limited receiver is tasked with collecting vital health data from multiple transmitters.