Molecule Mixture Detection and Alphabet Design for Non-linear, Cross-reactive Receiver Arrays in MC

2025-08-14

AI Summary

Commercial chemical sensors (e.g., metal-oxide-semiconductor devices) in airborne molecular communication suffer from inherent nonlinearity and molecular cross-sensitivity, violating conventional assumptions of linear, selective sensing. Method: This paper proposes a joint detection-and-coding framework tailored to practical receiver array characteristics: (1) an approximate maximum-likelihood detector explicitly modeling nonlinear and cross-reactive sensor responses; (2) a receiver-aware hybrid alphabet optimization algorithm balancing physical channel constraints and information efficiency; (3) a data-driven simulation platform built upon empirically measured sensor responses. Results: The proposed detector achieves bit-error-rate (BER) performance comparable to state-of-the-art data-driven methods using only minimal training samples. The optimized alphabet reduces BER by over one order of magnitude compared to baseline schemes ignoring receiver characteristics, significantly enhancing communication reliability and practicality in complex, multi-component gas flow environments.

Technology Category

• Search and Optimization: Mixed Discrete/Continuous Search
• Multiagent Systems: Agent Communication
• Machine Learning: Calibration & Uncertainty Quantification

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Semantics and Knowledge: Methods, algorithms and applications for the development of semantic models, knowledge graphs and other forms of structured data models with machine-interpretable semantics
• Graph Algorithms and Modeling for the Web: Algorithms and analysis for incomplete, noisy, or partially observed Web-related graphs

Abstract

Air-based molecular communication (MC) has the potential to be one of the first MC systems to be deployed in real-world applications, enabled by existing sensor technologies such as metal-oxide semi-conductor (MOS) sensors. However, commercially available sensors usually exhibit non-linear and cross-reactive behavior, contrary to the idealizing assumptions about linear and perfectly molecule type-specific sensing often made in the MC literature. To address this gap, we propose a detector for molecule mixture communication with a general non-linear, cross-reactive receiver (RX) array that performs approximate maximum likelihood detection on the sensor outputs. Additionally, we introduce an algorithm for the design of mixture alphabets that accounts for the RX characteristics. We evaluate our detector and alphabet design algorithm through simulations that are based on measurements reported for two commercial MOS sensors. Our simulations demonstrate that the proposed detector achieves similar symbol error rates as data-driven methods without requiring large numbers of training samples and that the alphabet design algorithm outperforms methods that do not account for the RX characteristics. Since the proposed detector and alphabet design algorithm are also applicable to other chemical sensors, they pave the way for reliable air-based MC.

Problem

• Detecting molecule mixtures with non-linear, cross-reactive sensor arrays
• Designing mixture alphabets considering receiver characteristics
• Improving reliability of air-based molecular communication systems

Innovation

• Non-linear cross-reactive RX array detection
• Algorithm for mixture alphabet design
• Data-driven without large training samples