Channel estimation techniques for diffusion-based molecular communications

Abstract

Abstract-In molecular communication (MC) systems, the expected number of molecules observed at the receiver over time after the instantaneous release of molecules by the transmitter is referred to as the channel impulse response (CIR). Knowledge of the CIR is needed for the design of detection and equalization schemes. In this paper, we present a training-based CIR estimation framework for MC systems which aims at estimating the CIR based on the observed number of molecules at the receiver due to emission of a sequence of known numbers of molecules by the transmitter. In particular, we derive maximum likelihood (ML) and least sum of square errors (LSSE) estimators. We also study the Cramer Rao (CR) lower bound and training sequence design for the considered system. Simulation results confirm the analysis and compare the performance of the proposed estimation techniques with the CR lower bound.

Molecular Channel Fading Due to Diffusivity Fluctuations

“…To the best of our knowledge, existing research [5] has assumed that the value of φ is constant for a fixed time and distance, and variations in the diffusion channel due to random environment changes have been neglected (i.e., channel fading has not been considered in a molecular communication context). Despite the abundance of additive noise based research [3], [4], [6], an examination of how variations in the channel gain itself affect performance has been lacking.…”

Active versus Passive: Receiver Model Transforms for Diffusive Molecular Communication

“…Other authors, such as in [8], [9], derived results that were valid for any model but did not compare models directly.…”