Molecular communications in vessel-like diffusive channels

Abstract

Molecular communication via diffusion is based on relaying information over a diffusive channel. The design of this diffusive channel is a vital issue. In this thesis, diffusion in the vessel-like environment, which is composed of a cylindrical environ ment resembling a blood vessel encompassing all the components of the communica tion system, is studied. Even though the range of communication increases in such environments due to the effect of the blood flow, vessel-like environments are not very suitable for analytical analysis. Therefore, many works, which considered vessel-like environment as the communication environment, are based on the simulation results rather than the analytical results. In order to fill this gap in the literature and to be able to localize the transmitter, we derive the analytical formulation of the channel model for diffusion-dominated movement, considering ring-shaped observing receivers and Poiseuille flow. Then, we derive formulations using this channel model for two different application scenarios, known and unknown emission time. A single receiver is used to localize the transmitter for known emission time, whereas two receivers are used for unknown emission time. Besides, as an alternative to signal-to-noise ratio (SNR), we propose MOL-Eye diagram and some metrics of this diagram (e.g., counting SNR) for the performance evaluation of a molecular signal. Also, binary concentration shift keying with consecutive power adjustment (BCSK-CPA) modulation technique is proposed to decrease destructive inter-symbol interference (ISI) effect and increase constructive ISI effect. Moreover, within the vessel-like environments, different values for the components of the environment (e.g., receiver, flow) are investigated. Lastly, partially covering receiver is proposed as a new type of receiver, and channel model of such environment is devised. Finally, all of the devised frameworks are validated with custom-made simulator