A diffusion-neuron hybrid channel for molecular communication

We propose a hybrid model which contains diffusion-based and neural sub-channels. In molecular communication, they are two kinds of the communication modes, with both merits and demerits. The realistic hub connecting the both subchannels is the diffusive Ca²+, which access the neurons via Ca²⁺ channels and produce various neural signals by regulating the vesicle release process. Based on this mechanism, the connector nano-machine (CNM) between the both sub-channels is used to alter the Ca²⁺ concentration for realizing hybrid channel communication. We code and decode the signal according to the distribution of the vesicle release time, which is directly influenced by the Ca²⁺ regulation. We deduce the mutual information and express the channel capacity using the information theory, substituting into the previous formulas. Comparing with relaying diffusive communication, the performance is verified in the simulation. Some major parameters related to the channel are also analyzed.