On Capacity Bounds of Two-Way Diffusion Channel with Molecule Harvesting

Abstract

In this paper, we investigate a binary two-way diffusion channel from an information theoretical perspective. Molecule harvesting is considered by which molecules can be reused by the receiver for subsequent transmissions. An outer bound of the capacity region for the general case and inner bounds for specific cases are derived. With the proposed outer bound, we show that no signaling rate is achievable in the considered system if messenger molecules perform free diffusion in an unconfined space and the nodes are not replenished with extra molecules. The proposed lower bounds are tighter than the ones resulted from the traditional joint typicality decoding method.