Impact of Evanescence Process on Three-Dimensional Sub-Diffusion-Based Molecular Communication Channel

Area of Science:

• Biomedical Engineering
• Chemical Engineering
• Theoretical Computer Science

Background:

• Existing molecular communication (MC) models typically assume standard diffusion, where molecule movement scales linearly with time.
• Real-world biological environments, like living cells, exhibit complex, crowded conditions leading to sub-diffusion, where molecule movement follows a fractional power law.
• Molecules can also degrade before reaching their target, a phenomenon known as evanescence, further complicating MC systems.

Purpose of the Study:

• To develop a 3D molecular communication system model incorporating sub-diffusion and molecule evanescence.
• To derive closed-form expressions for molecule arrival probability and first passage time density in this complex channel.
• To analyze the performance of MC systems using concentration-based modulation in a sub-diffusion environment.

Main Methods:

• A 3D point transmitter (TX) and spherical receiver (RX) model was established.
• Sub-diffusion dynamics and molecule evanescence were incorporated into the MC system.
• Closed-form expressions for arrival probability and first passage time density were derived.
• Concentration-based modulation was employed to evaluate system performance.

Main Results:

• The study presents novel closed-form expressions for key MC parameters under sub-diffusion and evanescence.
• Performance analysis using concentration-based modulation reveals the impact of reaction rate, fractional power, and receiver radius.
• The developed model accurately captures MC behavior in complex biological environments.

Conclusions:

• The proposed MC model provides a more realistic representation of communication in crowded cellular environments.
• Understanding sub-diffusion and evanescence is crucial for designing efficient MC systems for biomedical applications.
• The findings offer valuable metrics for optimizing MC system design, including probability of detection, false alarm, and error rates.