Airborne Particle Communication Through Time-varying Diffusion-Advection Channels

Particle based communication using diffusion and advection has emerged as an alternative signaling paradigm recently. While most existing studies assume constant flow conditions, real macro scale environments such as atmospheric winds exhibit time varying behavior. In this work, airborne particle communication under time varying advection is modeled as a linear time varying (LTV) channel, and a closed form, time dependent channel impulse response is derived using the method of moving frames. Based on this formulation, the channel is characterized through its power delay profile, leading to the definition of channel dispersion time as a physically meaningful measure of channel memory and a guideline for symbol duration selection. System level simulations under directed, time varying wind conditions show that waveform design is critical for performance, enabling multi symbol modulation using a single particle type when dispersion is sufficiently controlled. The results demonstrate that time varying diffusion advection channels can be systematically modeled and engineered using communication theoretic tools, providing a realistic foundation for particle based communication in complex flow environments.