  Within the domain of molecular communications, researchers mimic the
techniques in nature to come up with alternative communication methods for
collaborating nanomachines. This work investigates the channel transfer
function for molecular communication via diffusion. In nature,
information-carrying molecules are generally absorbed by the target node via
receptors. Using the concentration function, without considering the absorption
process, as the channel transfer function implicitly assumes that the receiver
node does not affect the system. In this letter, we propose a solid analytical
formulation and analyze the signal metrics (attenuation and propagation delay)
for molecular communication via diffusion channel with an absorbing receiver in
a 3-D environment. The proposed model and the formulation match well with the
simulations without any normalization.
