Optimizing the Spatial Topology of Bacterial Relay Systems: Delay Minimization
Diffusion-based molecular communication (DBMC) between spatially separated bacterial colonies has limited range due to slow diffusive propagation. To this end, relay-aided DBMC with bacterial colonies as nodes is considered in this paper. A deterministic framework that governs the overall system behavior is provided for amplify-and-forward (AF) type relays. Motivated by real-life constraints in practical implementation, the framework is expanded to cover a maximum saturation limit on emission intensity, yielding the AF-with saturation (AFS) relay model. For n-hop bacterial DBMC with AFS relays, a trade-off between diffusion delay and relay processing time is investigated, which hints to an optimal number of relays that minimizes end-to-end delay. A tractable objective function for the end-to-end delay is provided by approximating the system as a cascade of n one-hop links. Numerical results show that the approximation is tight, and up to 50% decrease in end-to-end delay can be achieved by optimizing the number of relays.
