Channel modeling of multilayer diffusion-based molecular nano communication system
In nanoscale communication, diffusion-based molecular communication (DBMC) in which information is encoded into molecule patterns by a transmitter nanomachine, has emerged as a promising communication system, particularly for biomedical and healthcare applications. Although, numerous studies have be...
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| Format: | Thesis |
| Published: |
2016
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| Online Access: | http://eprints.uthm.edu.my/9220/ http://eprints.uthm.edu.my/9220/1/Saizal_Mursidi_Md_Mustam.pdf |
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| Summary: | In nanoscale communication, diffusion-based molecular communication
(DBMC) in which information is encoded into molecule patterns by a transmitter
nanomachine, has emerged as a promising communication system, particularly for
biomedical and healthcare applications. Although, numerous studies have been
conducted to evaluate and analyze DBMC systems, investigation on DBMC system
through a multilayer channel has received less attention. The aims of this research are
to mathematically model a closed-form expression of mean molecular concentration
over multilayer DBMC channel, to formulate channel characteristics, and to conduct
performance evaluation of multilayer DBMC channel. In the mathematical model, the
propagation of molecules over an n-layer channel is assumed to follow the Brownian
motion and subjected to Fick’s law of diffusion. The partial differential equation (PDE)
of the time rate change of molecular concentration is obtained by modeling the n-layer
channel as an n-resistor in series and considering the conservation law of molecules.
Fourier transform and Laplace transform were used to obtain the solution for the PDE,
which represents the mean molecular concentration at a receiver nanomachine. In the
formulation, channel characteristics such as impulse response, time delay, attenuation
or the maximum peak, delay spread and capacity were analytically obtained from the
mean molecular concentration. In this stage, the multilayer channel is considered as
a linear and deterministic channel. For the performance evaluation, the air-waterblood
plasma medium representing the simplified multilayer diffusion model in the
respiratory system was chosen. It was found that both analytical and simulation results
of mean molecular concentration using Matlab and N3Sim were in good agreement.
In addition, the findings showed that the higher the average diffusion coefficient
resulted in a smaller dispersion of channel impulse response, and shortened the
channel delay spread as well as time delay. However, the channel attenuation remains
unchanged. In the performance evaluation, an increase of 100% in the transmission
distance increased the time delay by 300% but decreased the maximum peak of
molecular concentration by 87.5%. A high channel capacity can be achieved with wide
transmission bandwidth, short transmission distance, and high average transmitted
power. These findings can be used as a guide in the development and fabrication
of future artificial nanocommunication and nanonetwork systems involving multilayer
transmission medium. Implication of this study is that modeling and analyzing
of multilayer DBMC channel are important to support biomedical applications as
diffusion can occur through a multilayer structure inside the human body. |
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