On the asynchronous information embedding for event-driven systems in molecular communications

Molecular communications is emerging as a promising paradigm for nanoscale communications in nanotechnology. Though still at an early stage, research efforts have been devoted and various molecular communication systems have been proposed. However, each proposed system possesses a specific structure to achieve communications in its own way. To our best knowledge, no unified system description exists so far. In this paper, we propose an abstract system structure called an event-driven system; a significant group of molecular communication systems can be classified into such an abstract form. We define event-driven systems and further show that, for these systems, there is a signaling scheme called asynchronous information embedding which carries additional information while at the same time keeping the original communication mechanisms uninfluenced. Instead of investigating asynchronous information embedding in full generality, we consider synchronous type-based systems as a demonstrative example which still captures most of the features. For such type-based systems, we develop an approximation method for obtaining the channel capacity as a general performance measure. Numerical results are provided to show the capacity gain of asynchronous information embedding.