Estimate-and-Forward Relaying in Molecular Communication using Brownian Motion with Drift

Abstract

In diffusion-based molecular communication (DMC) systems, the information-bearing molecular signal experiences high attenuation with long propagation delays. It is thereby essential to deploy an intermediate relay nanomachine to alleviate such problem. In this paper, we propose and investigate an estimate-and-forward (EF) relaying scheme for a two-hop DMC system using Brownian motion with drift. Moreover, we consider the quasi-constant statistics of residual and counting noises to account for the aberrations present in the system. The considered relaying scheme forwards an estimate of the transmitted number of molecules, which is derived based on maximum likelihood principle. Further, we obtain an expression for the end-to-end error probability by making use of energy detector. Numerical and simulation results validate our analysis and reveal the scenarios where EF scheme can be beneficial over the existing amplify-and-forward and decode-and-forward relaying schemes.