Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Multi Ratio Shift Keying (MRSK) for Molecular Communication

Boran A. Kilic, Ozgur B. Akan

TL;DR

This work introduces Multi Ratio Shift Keying (MRSK), a ratio-based modulation for diffusion-only molecular communication that encodes information in the ratios of multiple molecule types. A mathematical framework for the ratio of Gaussian random variables is developed, including a solid approximation and a Gaussian surrogate, to enable analytical BER analysis and to support fixed-threshold and adaptive detection schemes. The authors propose three detectors—Fixed Threshold Detection (FTD), Adaptive Detection with Memory Cancellation (ADMC), and ML sequence detection—and demonstrate via analysis and Smoldyn simulations that MRSK can significantly outperform traditional MC modulations, particularly under ISI-heavy or high-rate scenarios. The findings suggest MRSK’s potential for flexible, high-throughput MC with channel-condition agnostic thresholds, highlighting its suitability for SIMO-like non-coherent reception and future integration into nano-biological networks.

Abstract

Molecular Communication (MC) leverages the power of diffusion to transmit molecules from a transmitter to a receiver. A wide variety of modulation techniques based on molecule concentration, type, and release time have been extensively studied in the literature. In this paper, we propose a novel modulation technique that encodes the information into the relative concentrations of multiple molecules called Multi Ratio Shift Keying (MRSK) designed for diffusion-based MC without drift. We show that leveraging all possible ratios in a set of molecules can help mitigate the effects of intersymbol interference (ISI) and provide a flexible communication channel. To evaluate the performance of the MRSK, we develop a mathematical framework for studying the statistics of the ratio of random variables, focusing on noncentral Gaussian distributions. We then assess MRSK performance both analytically and through particle-based simulations under various channel conditions, identifying potential sources of error in our system model. Additionally, we conduct a comparative analysis of commonly used modulation schemes in the literature based on bit error rate (BER). The results show that MRSK significantly outperforms all traditional modulation schemes considered in this study in terms of BER. MRSK offers a promising, flexible, and more reliable communication method for the future of the MC paradigm.

Multi Ratio Shift Keying (MRSK) for Molecular Communication

TL;DR

This work introduces Multi Ratio Shift Keying (MRSK), a ratio-based modulation for diffusion-only molecular communication that encodes information in the ratios of multiple molecule types. A mathematical framework for the ratio of Gaussian random variables is developed, including a solid approximation and a Gaussian surrogate, to enable analytical BER analysis and to support fixed-threshold and adaptive detection schemes. The authors propose three detectors—Fixed Threshold Detection (FTD), Adaptive Detection with Memory Cancellation (ADMC), and ML sequence detection—and demonstrate via analysis and Smoldyn simulations that MRSK can significantly outperform traditional MC modulations, particularly under ISI-heavy or high-rate scenarios. The findings suggest MRSK’s potential for flexible, high-throughput MC with channel-condition agnostic thresholds, highlighting its suitability for SIMO-like non-coherent reception and future integration into nano-biological networks.

Abstract

Molecular Communication (MC) leverages the power of diffusion to transmit molecules from a transmitter to a receiver. A wide variety of modulation techniques based on molecule concentration, type, and release time have been extensively studied in the literature. In this paper, we propose a novel modulation technique that encodes the information into the relative concentrations of multiple molecules called Multi Ratio Shift Keying (MRSK) designed for diffusion-based MC without drift. We show that leveraging all possible ratios in a set of molecules can help mitigate the effects of intersymbol interference (ISI) and provide a flexible communication channel. To evaluate the performance of the MRSK, we develop a mathematical framework for studying the statistics of the ratio of random variables, focusing on noncentral Gaussian distributions. We then assess MRSK performance both analytically and through particle-based simulations under various channel conditions, identifying potential sources of error in our system model. Additionally, we conduct a comparative analysis of commonly used modulation schemes in the literature based on bit error rate (BER). The results show that MRSK significantly outperforms all traditional modulation schemes considered in this study in terms of BER. MRSK offers a promising, flexible, and more reliable communication method for the future of the MC paradigm.
Paper Structure (20 sections, 47 equations, 12 figures)

This paper contains 20 sections, 47 equations, 12 figures.

Table of Contents

  1. Introduction
  2. System Model and Ratio of Random Variables
  3. General System Topology
  4. Ratio of Gaussian Random Variables
  5. Multi Ratio Shift Keying
  6. Transmission
  7. Detection
  8. Fixed Threshold Detection (FTD)
  9. Adaptive Detection with Memory Cancellation (ADMC)
  10. ML sequence detection
  11. Bit Error Rate analysis
  12. Performance Evaluation
  13. Effect of M and N Values
  14. Effect of Channel Conditions
  15. Bit Time
  16. ...and 5 more sections

Figures (12)

  • Figure 1: General systems topology of MRSK. Different colors represent different molecules.
  • Figure 2: Plots of PDFs of the received ratio when transmitted ratios are $e$, $e^{-1}$ and $1$ .
  • Figure 3: PDF plots of the received ratios for release ratios $x_{M=3}$ .
  • Figure 4: Normalized average number of molecules used per bit in MRSK for a range of $N$, $M$ parameters.
  • Figure 5: BER vs $N$ and $M$ curves for $t_b=0.5$s .
  • ...and 7 more figures