Molecular communication in diffusion based channel

Abstract

This thesis deals with diffusion based molecular communication. Unlike conven tional communication systems, the information is encoded with molecules and these molecules are emitted by nanodevices in a diffusive environment. Since the molecules diffuse through the environment, their movement is governed by Brownian Motion, resulting in very slow and random movement that leads to excessive interference com pared to conventional communication channels. In this thesis, various modulation, equalization and coding schemes are proposed to combat with this interference issue. The main motivation for the determination of these schemes is proposing computa tionally simple and/or sparse communication methods suitable for nanodevices. All proposed methods diminish the interference at the received signal and improve the performance of the molecular communication channels compared to the other exist ing methods in the literature. In particular, pulse position modulation is adopted for molecular communication channel to diminish interference without any additional complexity and less channel information compared to other proposed modulations. A specific sparse channel code for molecular communication is also proposed by present ing its improved performance. For equalization, the received signal is equalized by analytically determining the optimum reception delay analytically that minimizes in terference and maximizes the signal power. With the same goal, optimum aperture region of the receiver is determined by deriving the joint angle-time distribution of the absorbed molecules at the receiver. Finally, network coding methods are proposed for two-way one-hop and multi-hop nanonetworks.