Performance Enhancement of Diffusion-Based Molecular Communication

Inter-Symbol Interference (ISI) is one of the challenges of bio-inspired diffusion-based molecular communication. The degradation of the remaining molecules from a previous transmission is the solution that biological systems use to mitigate this ISI. While most prior work has proposed the use of enzymes to catalyze the molecules degradation, enzymes also degrade the molecules carrying the information, which drastically decreases the signal strength. In this paper, we propose the use of photolysis reactions, which use the light to instantly transform the emitted molecules so they no longer be recognized after their detection. The light will be emitted in an optimal time, allowing the receiver to detect as many molecules as possible, which increases both the signal strength and ISI mitigation. A lower bound expression on the expectation of the observed molecules number at the receiver is derived. Bit error probability expression is also formulated, and both expressions are validated with simulation results, which show a visible enhancement when using photolysis reactions. The performance of the proposed method is evaluated using Interference-to-Total-Received molecules metric (ITR) and the derived bit error probability.