Channel Codes for Reliability Enhancement in Molecular Communication

TLDR

Molecular communications is a promising scheme for nanoscale device communication, but diffusion‑based systems suffer from molecule crossovers that cause intersymbol interference. The paper introduces ISI‑free channel codes to enhance reliability while maintaining low decoding complexity in Brownian‑motion diffusion environments. The authors present encoding/decoding schemes that transmit a fixed number of identical molecules per symbol and derive a mathematical BER approximation to guide performance analysis. Compared to uncoded systems, the ISI‑free codes achieve good performance with reasonably low complexity in diffusion‑based molecular communication.

Abstract

Molecular communications emerges as a promising scheme for communications between nanoscale devices. In diffusion-based molecular communications, molecules as information symbols diffusing in the fluid environments suffer from molecule crossovers, i.e., the arriving order of molecules is different from their transmission order, leading to intersymbol interference (ISI). In this paper, we introduce a new family of channel codes, called ISI-free codes, which improve the communication reliability while keeping the decoding complexity fairly low in the diffusion environment modeled by the Brownian motion. We propose general encoding/decoding schemes for the ISI-free codes, working upon the modulation schemes of transmitting a fixed number of identical molecules at a time. In addition, the bit error rate (BER) approximation function of the ISI-free codes is derived mathematically as an analytical tool to decide key factors in the BER performance. Compared with the uncoded systems, the proposed ISI-free codes offer good performance with reasonably low complexity for diffusion-based molecular communication systems.