Improving Receiver Performance of Diffusive Molecular Communication with Enzymes

This paper studies the mitigation of intersymbol interference in a diffusive molecular communication system using enzymes that freely diffuse in the propagation environment. The enzymes form reaction intermediates with information molecules and then degrade them so that they cannot interfere with future transmissions. A lower bound expression on the expected number of molecules measured at the receiver is derived. A simple binary receiver detection scheme is proposed where the number of observed molecules is sampled at the time when the maximum number of molecules is expected. Insight is also provided into the selection of an appropriate bit interval. The expected bit error probability is derived as a function of the current and all previously transmitted bits. Simulation results show the accuracy of the bit error probability expression and the improvement in communication performance by having active enzymes present.Comment: 13 pages, 8 figures, 1 table. To appear in IEEE Transactions on Nanobioscience (submitted January 22, 2013; minor revision October 16, 2013; accepted December 4, 2013

Improving Diffusion-Based Molecular Communication with Unanchored Enzymes

In this paper, we propose adding enzymes to the propagation environment of a diffusive molecular communication system as a strategy for mitigating intersymbol interference. The enzymes form reaction intermediates with information molecules and then degrade them so that they have a smaller chance of interfering with future transmissions. We present the reaction-diffusion dynamics of this proposed system and derive a lower bound expression for the expected number of molecules observed at the receiver. We justify a particle-based simulation framework, and present simulation results that show both the accuracy of our expression and the potential for enzymes to improve communication performance.Comment: 15 pages, 4 figures, presented at the 7th International Conference on Bio-Inspired Models of Network, Information, and Computing Systems (BIONETICS 2012) in Lugano, Switzerlan

Hubungan antara tahap kompetensi dengan tahap prestasi kerja di kalangan pentadbir Kolej Universiti Teknologi Tun Hussein Onn (KUiTTHO)

This research is a case research in studying the connection of competency level with the administrator in Kolej University Teknologi Tun Hussein Onn (KUiTTHO). Research was done on 40 respondents which were identified playing an important role in giving the feedback. All the respondents are a public service officer from the management and professional group in KUiTTHO, Batu Pahat, Johor. Results from the research are gathered using the Statistical Package for Social Sciences (SPSS version 13.0) software. Model for the Managers Competency and KUiTTHO Annual Assessment Report Form are the main components in the establishing the research framework. As for the independent variable, competencies are divided into four clusters which is personal management, group management, working management and collaborative management. While the dependent variable which is job performance is divided into three dimensions which are working result, knowledge and ability and personal quality. Throughout the research the result shows that the competency level and job performance level for the KUiTTHO administrator are at the highest level. Based on Pearson correlation analysis, research result shows that the positive relationship exists is at the average level. However, competency levels are still playing a huge role in increasing the level of the administrator job performance in KUiTTHO

A Unifying Model for External Noise Sources and ISI in Diffusive Molecular Communication

This paper considers the impact of external noise sources, including interfering transmitters, on a diffusive molecular communication system, where the impact is measured as the number of noise molecules expected to be observed at a passive receiver. A unifying model for noise, multiuser interference, and intersymbol interference is presented, where, under certain circumstances, interference can be approximated as a noise source that is emitting continuously. The model includes the presence of advection and molecule degradation. The time-varying and asymptotic impact is derived for a series of special cases, some of which facilitate closed-form solutions. Simulation results show the accuracy of the expressions derived for the impact of a continuously-emitting noise source, and show how approximating intersymbol interference as a noise source can simplify the calculation of the expected bit error probability of a weighted sum detector.Comment: 14 pages, 7 figures, 4 tables, 1 appendix. To appear in IEEE Journal on Selected Areas in Communications (JSAC). Submitted October 21, 2013, revised April 21, 2014, accepted June 3, 201

A revised look at the effects of the Channel Model on molecular communication system

Molecular communications, where information is passed between the Transmitter (TX) and the Receiver (RX) via molecules is a promising area with vast potential applications. However, the infancy of the topic within the overall taxonomy of communications has meant that to date, several channel models are in press, each of which is applied under various constraints and/or assumptions. Amongst them is that the arrival of molecules in different time slots can be, or is, considered as independent events. In practice, this assumption is not accurate, as the molecules arriving in the previous slot reduce the possible number of molecules in the next slot and hence make them correlated. In this letter, we analyze a more realistic performance of a molecular communication assuming correlated events. The key result shown, is that the widely used model assuming independent events significantly overestimates the error rates in the channel. This result is thus critical to researchers who focus on energy use at the nano-scale, as the new analysis provides a more realistic prediction and therefore, less energy will be needed to attain a desired error rate, increasing system feasibility

An M\textit{M}-ary Concentration Shift Keying With Common Detection Thresholds For Multi-Transmitter Molecular Communication

Concentration shift keying (CSK) is a widely adopted modulation technique for molecular communication-based nanonetworks, which is a key enabler for the Internet of Bio-NanoThings (IoBNT). However, existing methods provide optimal error performance at the cost of high operational complexity that scales poorly as the number of transmitters, $K$, increases. This paper proposes a novel $M$-ary CSK method termed CSK with Common detection Thresholds (CSK-CT). CSK-CT uses $\textit{common}$ thresholds that are sufficiently low to ensure the reliable detection of symbols transmitted by every transmitter, regardless of their distance. We derive closed-form expressions to obtain the common thresholds and release concentrations. To enhance the error performance, we optimize the release concentration using a scaling exponent that further optimizes the common thresholds. We evaluate the performance of CSK-CT in comparison to the benchmark CSK for varying values of $K$ and $M$. In terms of the error probability, CSK-CT offers between $10^{-7}$ and $10^{-4}$, which are a substantial improvement from the $10^{-4}$ to $10^{-3}$ offered by the benchmark. In terms of complexity, CSK-CT is $\textit{O}\big(n\big)$ and does not scale with $K$ but $M$ ($M\ll K$), while the benchmark is $\textit{O}\big(n^2\big)$. Furthermore, CSK-CT showcased the ability to mitigate inter-symbol interference, although this facet warrants further investigation. Due to its low error probability, improved scalability, low complexity, and potential ISI mitigation features, CSK-CT demonstrates benefits in applications of IoBNT focused on data-gathering. Specifically, its utility is well-noted in settings where a computationally strained receiver collects sensitive health-related data from multiple transmitters.Comment: Submitted to IEEE for possible publicatio

Conception et évaluation de nouvelles méthodes pour améliorer les performances des réseaux de nano-communication

Abstract : The field of nanotechnology has undergone very rapid and fascinating development in recent years. This rapid and impressive advance has led to new applications of nanotechnology in the biomedical and military industries, making it a key area of research in multidisciplinary fields. However, the individual processing capacity of nanodevices is very limited, hence the need to design nanonetworks that allow the nanodevices to share information and to cooperate with each other. There are two solutions to establish a nanocommunication system: either by adapting the classical electromagnetic communication to the requirements of nano scale, or by using biological nanosystems inspired by nature such as the molecular communication proposed in the literature. In this thesis, we are interested in the second solution, which is exploiting the potential of biological nanosystems used by nature since billions of years to design biocompatible nanonetworks that can be used inside the human body for medical applications. Nevertheless, the use of this new paradigm is not without challenges. The very low achievable throughput and the Inter-Symbol Interference (ISI) are the most influential problems on the quality of molecular communication. The main objective of this thesis is to design and evaluate new methods inspired by nature in order to enhance the performance of nano-communication systems. To do this, the work is divided into three main parts. In the first part, we enhance the performance of molecular communication by proposing a new method that uses a photolysis-reaction instead of using enzyme to better attenuate ISI. We also propose an optimization of the receiver used in MIMO systems by judiciously choosing the parameters used in its design to reduce the influence of path loss on the quality of the system. The second part proposes a new wired nano-communication system based on self-assembled polymers that build an electrically conductive nanowire to connect the nanodevices to each other. The use of electrons as information carriers drastically increases the achievable throughput and reduces the delay. We study the dynamic process of self-assembly of the nanowire and we propose a bio-inspired receiver that detects the electrons sent through the conductive nanowire and converts them into a blue light. The third part applies the proposed wired nano-communication system to design an architecture ofWired Ad hoc NanoNETworks (WANNET) with a physical layer, Medium Acess Control (MAC) layer and application layer. We also calculate the maximum throughput and we evaluate the performance of the system.Le domaine des nanotechnologies a connu un développement très rapide et fascinant ces dernières années. Cette avancée rapide et impressionnante a conduit à de nouvelles applications dans les industries biomédicale et militaire, ce qui en fait un champ clé de recherche dans des domaines multidisciplinaires. Cependant, la capacité de traitement individuelle des nanodispositifs est très limitée, d'où la nécessité de concevoir des nanoréseaux qui permettent aux nanodispositifs de partager des informations et de coopérer entre eux. Il existe deux solutions pour mettre en place un système de nano-communication: soit en adaptant la communication électromagnétique classiques aux exigences de la nano échelle, soit en utilisant des nanosystèmes inspirés de la nature comme la communication moléculaire. Dans cette thèse, nous nous intéressons à la deuxième solution, qui exploite le potentiel des nanosystèmes biologiques utilisés par la nature depuis des milliards d'années pour concevoir des nanoréseaux biocompatibles pouvant être utilisés à l'intérieur du corps humain pour des applications médicales. Néanmoins, l'utilisation de ce nouveau paradigme n'est pas sans défis. Le très faible débit réalisable et l'Interférence Entre Symboles (IES) sont les problèmes les plus influents sur la qualité de la communication moléculaire. L'objectif principal de cette thèse est de concevoir et d'évaluer de nouvelles méthodes inspirées de la nature afin d'améliorer les performances des systèmes de nano-communication. Pour ce faire, le travail est divisé en trois parties principales. Dans la première partie, nous améliorons les performances de la communication moléculaire en proposant une nouvelle méthode qui utilise une réaction de photolyse pour mieux atténuer l'IES. Nous proposons également une optimisation du receveur utilisé dans les systèmes MIMO en choisissant judicieusement les paramètres utilisés dans sa conception pour réduire l'influence de l'atténuation de trajet sur la qualité du système. La deuxième partie propose un nouveau système de nano-communication filaire basé sur des polymères auto-assemblés qui construisent un nanofil électriquement conducteur pour connecter les nanodispositifs les uns aux autres. L'utilisation d'électrons comme supports d'informations augmente considérablement le débit réalisable et réduit le délai. Nous étudions le processus dynamique d'auto-assemblage du nanofil et nous proposons un receveur bio-inspiré qui détecte les électrons envoyés et les convertit en une lumière bleue. La troisième partie applique le système de nano-communication filaire proposé pour concevoir une architecture d'un nanoréseau ad hoc filaire (Wired Ad hoc NanoNETworks) WANNET avec une couche physique, une couche de contrôle d'accès moyen (Medium Access Control) MAC et une couche d'application. Nous calculons également le débit maximum et nous évaluons les performances du système

Fundamentals of diffusion-based molecular communication in nanonetworks

Molecular communication (MC) is a promising bio-inspired paradigm for the exchange of information among nanotechnology-enabled devices. These devices, called nanomachines, are expected to have the ability to sense, compute and actuate, and interconnect into networks, called nanonetworks, to overcome their individual limitations and benefit from collaborative efforts. MC realizes the exchange of information through the transmission, propagation, and reception of molecules, and it is proposed as a feasible solution for nanonetworks. This idea is motivated by the observation of nature, where MC is successfully adopted by cells for intracellular and intercellular communication. MC-based nanonetworks have the potential to be the enabling technology for a wide range of applications, mostly in the biomedical, but also in the industrial and surveillance fields. The focus of this Ph.D. thesis is on the most fundamental type of MC, i.e., diffusion-based MC, where the propagation of information-bearing molecules between a transmitter and a receiver is realized through free diffusion in a fluid. The objectives of the research presented in this thesis are to analyze the MC paradigm from the point of view of communication engineering and information theory, and to provide solutions to the modeling and design of MC-based nanonetworks. First, a physical end-to-end model is realized to study each component in a basic diffusion-based MC system design, as well as the overall system, in terms of gain and delay. Second, the noise sources affecting a diffusion-based MC are identified and statistically modeled. Third, upper/lower bounds to the capacity are derived to evaluate the information-theoretic performance of diffusion-based MC. Fourth, a stochastic analysis of the interference when multiple transmitters access the diffusion-based MC channel is provided. Fifth, as a proof of concept, a design of a diffusion-based MC system built upon genetically-engineered biological circuits is analyzed. This research provides fundamental results that establish a basis for the modeling, design, and realization of future MC-based nanonetworks, as novel technologies and tools are being developed.Ph.D