Performance Evaluation and Optimal Detection of Relay-Assisted Diffusion-Based Molecular Communication With Drift.

Area of Science:

• Biomedical Engineering
• Molecular Communication
• Nanotechnology

Background:

• Molecular communication (MC) systems utilize molecules for information transmission.
• Relay-assisted strategies are crucial for enhancing reliability in complex environments like the human bloodstream.
• Diffusion-based MC faces challenges due to Brownian motion and environmental factors.

Purpose of the Study:

• To analyze the performance of a decode-and-forward (DF) relay-assisted diffusion-based molecular communication system within a human blood vessel.
• To derive a closed-form expression for the bit error probability (BEP) using normal approximation.
• To optimize the system's detection threshold for minimizing BEP.

Main Methods:

• Modeling a DF relay-assisted MC system in a positive drift environment (blood vessel).
• Applying normal approximation to the distribution of received molecules.
• Deriving a closed-form expression for end-to-end BEP.
• Formulating and solving an optimization problem for the optimal detection threshold using the bisection method.

Main Results:

• A closed-form expression for BEP was successfully derived.
• The bisection method effectively determined the optimal detection threshold.
• System performance was analyzed concerning drift velocity, relay position, and molecule count.
• Numerical results demonstrated significant BEP reduction with DF relaying under a constant molecular budget.

Conclusions:

• Decode-and-forward relaying is a viable strategy for improving reliability in diffusion-based molecular communication within biological environments.
• The proposed optimization framework effectively minimizes bit error probability.
• Understanding the impact of system parameters is key to designing efficient in-body molecular communication networks.