Emission rate optimization in diffusion-based molecular communication among mobile bacteria

In quorum sensing (QS), bacteria exchange information by using molecular signals to work together. In this paper, we study diffusion-based molecular communication with the QS mechanism between the transmitter node and receiver node which are composed of a population of mobile bacteria in a cluster, respectively. The expression of average bit error probability (BEP) at a receiver bacterium is derived. Furthermore, we use the projected gradient descent (PGD) algorithm to solve the optimization problem whose objective is to minimize the average BEP under emission rate constraints which require that the emission rate of each transmitter bacterium has lower and upper bounds. Finally, the numerical results show the PGD algorithm has good convergence behaviors and it is more efficient in finding the optimal emission rate with fewer iterations than genetic algorithm. The obtained results are expected to provide guidance in designing QS-based molecular communication system with lower average BEP.