Molecular Channel Fading Due to Diffusivity Fluctuations

Uncertainty Quantification in Molecular Signals Using Polynomial Chaos Expansion

“…In molecular signaling, when the propagation channel is described by a stable mass diffusion equation, the uncertainty arises from Brownian motion [15]. However, when there are fluctuations in the diffusion channel from temperature and diffusivity variations, then uncertainty in the channel propagates to the receiver signal concentration [16]. As evidenced by the literature, there is a lack of uncertainty research in molecular communications under complex fluid dynamic forces.…”

“…c 0 is the amount of the molecules which are released into the channel at t = 0, and v is the velocity field of the environment flow. Generally, there are two restrictions in solving (16). First of all, v is a function of the space and time which means that in any arbitrarily location and time, the velocity components should be calculated and substituted in (16) in order to find concentration distribution.…”

“…Generally, there are two restrictions in solving (16). First of all, v is a function of the space and time which means that in any arbitrarily location and time, the velocity components should be calculated and substituted in (16) in order to find concentration distribution. In the literature [2], this restriction has been ignored and they considered the velocity field constant spatially to find a closed-form relation for the concentration distribution.…”

“…Based on the discussed restrictions, considering anisotropic velocity and eddy diffusivity and also, considering time-variant velocity simultaneously makes the problem complicated and finding a closed-form solution is almost impossible. In order to address the foregoing problem, the velocity distribution should be obtained and employed in (16). One of the scheme to obtain the velocity distribution is using the numerical packages to simulate the flow field and solve the Reynolds-Average-Navier-Stokes (RANS) equations [24].…”

Bacterial Relay for Energy-Efficient Molecular Communications

“…However, its performance has important drawbacks such as low capacity, high latency, and sensitivity to environmental parameters [9]. For example, the in vivo diffusion environment can change relatively quickly due to the movement of cells, changes in temperature and diffusivity [10], as well as absorption and predation from other cells. If the diffusive process occurs over a long distance (i.e., hormone pathways), the reliability of sequential encoded information can degrade significantly.…”