Achievable information rates for molecular communication with distinct molecules

In molecular communication, messages are conveyed from a transmitter to a receiver by releasing a pattern of molecules at the transmitter, and allowing those molecules to propagate through a fluid medium towards a receiver. In this paper, achievable information rates are estimated for a molecular communication system when information is encoded using a set of distinct molecules, and when the molecules propagate across the medium via Brownian motion. Results are provided which indicate large gains in information rate over the case where the released molecules are indistinguishable from each other.