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1
Tseliou, Georgia. "Network virtualization in next generation cellular networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667301.
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The complexity of operation and management of emerging cellular networks significantly increases, as they evolve to correspond to increasing QoS needs, data rates and diversity of offered services. Thus critical challenges appear regarding their performance. At the same time, network sustainability pushes toward the utilization of haring Radio Access Network (RAN) infrastructure between Mobile Network Operators (MNOs). This requires advanced network management techniques which have to be developed based on characteristics of these networks and traffic demands. Therefore it is necessary to provide solutions enabling the creation of logically isolated network partitions over shared physical network infrastructure. Multiple heterogeneous virtual networks should simultaneously coexist and support resource aggregation so as to appear as a single resource to serve different traffic types on demand.
Hence in this thesis, we study RAN virtualization and slicing solutions destined to tackle these challenges. In the first part, we present our approach to map virtual network elements onto radio resources of the substrate physical network, in a dense multi-tier LTE-A scenario owned by a MNO. We propose a virtualization solution at BS level, where baseband modules of distributed BSs, interconnected via logical point-to-point X2 interface, cooperate to reallocate radio resources on a traffic need basis. Our proposal enhances system performance by achieving 53% throughput gain compared with benchmark schemes without substantial signaling overhead. In the second part of the thesis, we concentrate on facilitating resource provisioning between multiple Virtual MNOs (MVNOs), by integrating the capacity broker in the 3GPP network management architecture with minimum set of enhancements. A MNO owns the network and provides RAN access on demand to several MVNOs. Furthermore we propose an algorithm for on-demand resource allocation considering two types of traffic. Our proposal achieves 50% more admitted requests without Service Level Agreement (SLA) violation compared with benchmark schemes. In the third part, we devise and study a solution for BS agnostic network slicing leveraging BS virtualization in a multi-tenant scenario. This scenario is composed of different traffic types (e.g., tight latency requirements and high data rate demands) along with BSs characterized by different access and transport capabilities (i.e., Remote Radio Heads, RRHs, Small Cells, SCs and future 5G NodeBs, gNBs with various functional splits having ideal and non-ideal transport network). Our solution achieves 67% average spectrum usage gain and 16.6% Baseband Unit processing load reduction compared with baseline scenarios. Finally, we conclude the thesis by providing insightful research challenges for future works.<br>La complejidad de la operación y la gestión de las emergentes redes celulares aumenta a medida que evolucionan para hacer frente a las crecientes necesidades de calidad de servicio (QoS), las tasas de datos y la diversidad de los servicios ofrecidos. De esta forma aparecen desafíos críticos con respecto a su rendimiento. Al mismo tiempo, la sostenibilidad de la red empuja hacia la utilización de la infraestructura de red de acceso radio (RAN) compartida entre operadores de redes móviles (MNO). Esto requiere técnicas avanzadas de gestión de redes que deben desarrollarse en función de las características especiales de estas redes y las demandas de tráfico. Por lo tanto, es necesario proporcionar soluciones que permitan la creación de particiones de red aisladas lógicamente sobre la infraestructura de red física compartida. Para ello, en esta tesis, estudiamos las soluciones de virtualización de la RAN destinadas a abordar estos desafíos. En la primera parte de la tesis, nos centramos en mapear elementos de red virtual en recursos de radio de la red física, en un escenario LTE-A de múltiples niveles que es propiedad de un solo MNO. Proponemos una solución de virtualización a nivel de estación base (BS), donde los módulos de banda base de BSs distribuidas, interconectadas a través de la interfaz lógica X2, cooperan para reasignar los recursos radio en función de las necesidades de tráfico. Nuestra propuesta mejora el rendimiento del sistema al obtener un rendimiento 53% en comparación con esquemas de referencia. En la segunda parte de la tesis, nos concentramos en facilitar el aprovisionamiento de recursos entre muchos operadores de redes virtuales móviles (MVNO), al integrar el capacity broker en la arquitectura de administración de red 3GPP con un conjunto míinimo de mejoras. En este escenario, un MNO es el propietario de la red y proporciona acceso bajo demanda (en inglés on-demand) a varios MVNOs. Además, para aprovechar al máximo las capacidades del capacity broker, proponemos un algoritmo para la asignación de recursos bajo demanda, considerando dos tipos de tráfico con distintas características. Nuestra propuesta alcanza 50% más de solicitudes admitidas sin violación del Acuerdo de Nivel de Servicio (SLA) en comparación con otros esquemas. En la tercera parte de la tesis, estudiamos una solución para el slicing de red independiente del tipo de BS, considerando la virtualización de BS en un escenario de múltiples MVNOs (multi-tenants). Este escenario se compone de diferentes tipos de tráfico (por ejemplo, usuarios con requisitos de latencia estrictos y usuarios con altas demandas de velocidad de datos) junto con BSs caracterizadas por diferentes capacidades de acceso y transporte (por ejemplo, Remote Radio Heads, RRHs, Small cells, SC y 5G NodeBs, gNBs con varias divisiones funcionales que tienen una red de transporte ideal y no ideal). Nuestra solución logra una ganancia promedio de uso de espectro de 67% y una reducción de la carga de procesamiento de la banda base de 16.6% en comparación con escenarios de referencia. Finalmente, concluimos la tesis al proporcionando los desafíos y retos de investigación para trabajos futuros.
2
Liu, Siqian. "Network Convergence in Multicarrier Hybrid Cellular Network." Diss., North Dakota State University, 2014. https://hdl.handle.net/10365/27505.
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In a multicarrier communication system with known channel state information at transmitter (CSIT), it is well-known that the water-filling power allocation scheme is optimal in achieving the Shannon capacity. However, in a multicarrier broadcast network (e.g. over-the-air TV network) without CSIT, the optimal power allocation among subcarriers is still unknown, largely due to the heterogeneity of the channel conditions associated with different receivers. In the first part of the thesis, the performance of a generic multicarrier broadcast network is thoroughly studied by exploiting the frequency diversity over subcarriers. In particular, the performance metric is first defined based on the relationship among broadcast transmission rate, coverage area and outage probability. In order to maximize the network performance, closed form expressions of the instantaneous mutual information (IMI) and the optimal power allocation schemes are derived for both low SNR and high SNR cases; upper and lower bounds are also provided to estimate broadcast coverage area in general SNR regime. Also we extend our discussion to the broadcast network with multiple collaborative transmitters. Extensive simulation results are provided to validate our analysis. In the second part of the thesis, we discuss the optimal performance of a generic broadcast cellular hybrid network. It is well known that the Dirty Paper Coding (DPC) achieves the channel capacity for multiuser degraded channels. However, the optimality of DPC remains unknown for non-degraded channel. Specifically, we derive the optimal interference pre-cancellation order for a DPC based broadcast and unicast hybrid network. Different DPC cancellation schemes are studied to maximize the hybrid capacity region. The conditions for each scheme being optimal are analytically derived. Both ergodic and outage capacity are considered as our performance metric. Our results show that the optimal interference pre-cancellation order varies with SNR and broadcast and unicast channel conditions. Moreover, in low SNR condition, the optimal power allocation scheme is derived to reach the maximal sum rate.
3
DeMarinis, Nicholas AF. "On LTE Security: Closing the Gap Between Standards and Implementation." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/791.
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Modern cellular networks including LTE (Long Term Evolution) and the evolving LTE- Advanced provide high-speed and high-capacity data services for mobile users. As we become more reliant on wireless connectivity, the security of voice and data transmissions on the network becomes increasingly important. While the LTE network standards provide strict security guidelines, these requirements may not be completely followed when LTE networks are deployed in practice. This project provides a method for improving the security of LTE networks by 1) characterizing a gap between security requirements defined in the standards and practical implementations, 2) designing a language to express the encoding formats of one of LTE’s network-layer protocols, 3) developing a compiler to translate a protocol description in our language into an implementation, and 4) providing recommendations on lessons learned during development of the language and compiler to support development of future protocols that employ formal representations. In this way, our work demonstrates how a formal language can be utilized to represent a cellular network protocol and serves as an example for further research on how adding formalism to network standards can help ensure that the security goals defined in the standards can be upheld in an implementation.
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Rakotomalala, Livaniaina Hary. "Network Decontamination Using Cellular Automata." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34095.
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We consider the problem of decontaminating a network where all nodes are infected by a virus. The decontamination strategy is performed using a Cellular Automata (CA) model in which each node of the network is represented by the automata cell and thus, the network host status is also mapped to the CA state (contaminated, decontaminating, decontaminated). All hosts are assumed to be initially contaminated and the status of each cell is synchronously updated according to a set of local rules, based on the state of its neighbourhood. Our goal is to find the set of local rules that will accomplish the decontamination in an optimal way. The metrics used to define optimality is the minimization of three metrics: the maximum number of decontaminating cells at each step, the required value of the immunity time of each cell and the number of steps to complete the sanitization algorithm.
In our research, we explore the designing of these local decontamination rules by refining the concept of the neighbourhood radius of CA with the addition of two new dimensions: Visibility Hop and Contamination Distance. Additionally, a research tool that help us manage our study have been developed.
5
Azari, Amin. "Energy Efficient Machine-Type Communications over Cellular Networks : A Battery Lifetime-Aware Cellular Network Design Framework." Licentiate thesis, KTH, Kommunikationssystem, CoS, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194416.
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Internet of Things (IoT) refers to the interconnection of uniquely identifiable smart devices which enables them to participate more actively in everyday life. Among large-scale applications, machine-type communications (MTC) supported by cellular networks will be one of the most important enablers for the success of IoT. The existing cellular infrastructure has been optimized for serving a small number of long-lived human-oriented communications (HoC) sessions, originated from smartphones whose batteries are charged in a daily basis. As a consequence, serving a massive number of non-rechargeable machine-type devices demanding a long battery lifetime is a big challenge for cellular networks. The present work is devoted to energy consumption modeling, battery lifetime analysis, and lifetime-aware network design for massive MTC services over cellular networks. At first, we present a realistic model for energy consumption of machine devices in cellular connectivity, which is employed subsequently in deriving the key performance indicator, i.e. network battery lifetime. Then, we develop an efficient mathematical foundation and algorithmic framework for lifetime-aware clustering design for serving a massive number of machine devices. Also, by extending the developed framework to non-clustered MTC, lifetime-aware uplink scheduling and power control solutions are derived. Finally, by investigating the delay, energy consumption, spectral efficiency, and battery lifetime tradeoffs in serving coexistence of HoC and MTC traffic, we explore the ways in which energy saving for the access network and quality of service for HoC traffic can be traded to prolong battery lifetime for machine devices. The numerical and simulation results show that the proposed solutions can provide substantial network lifetime improvement and network maintenance cost reduction in comparison with the existing approaches.<br><p>QC 20161103</p>
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Larsson, Martin, and Anton Silfver. "Signal-aware adaptive timeout in cellular networks : Analysing predictability of link failure in cellular networks based on network conditions." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138128.
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Cellular networks are becoming more common, this introduces new challenges in dealing with their error prone nature. To improve end-to-end performance when the first link in the connection is wireless, an adaptive timeout based on network conditions is constructed. Relevant network factors are identified by examining data collected by a device located in a vehicle moving around in southern Sweden. Channel Quality Indicator (CQI) is shown to be the primary predictor of errors in the connection. In our datasets, a CQI index of 2 is a very good predictor of an error prone state. The collected data is split into training and evaluation data, the training data is used to construct a model. An adaptive timeout mechanism which uses this model is proposed, the mechanism is shown to be superior in all tested cases in the dataset compared to the optimal static counterpart. Reducing timeouts allows for applications to make new decisions based on new information faster, increasing responsiveness and user satisfaction.
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Manssour, Jawad. "Network Coding in Uplink Cellular Systems." Thesis, KTH, Kommunikationssystem, CoS, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48936.
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Ever since its introduction, network coding has attracted a lot of interest from the research community. This interest is a result of two main factors: the simplicity of application of network coding and the possibility to apply it to a plethora of applications. Research in network coding started on wired networks for different types of traffic, mainly focusing on code design, content distribution and network security. However, researchers soon came to realize that the inherent properties of the wireless medium render it a fertile ground for the application of network coding. This has resulted in tremendous research efforts on wireless applications of network coding for wireless systems, both academically and industrially, with the majority of these works targeting bidirectional traffic scenarios. In this work, we focus on practical implementation issues for network coding when applied to uplink cellular traffic. We provide our own relaying scheme based on decode-and-forward relays and network coding with a specially designed method of decoding at the receiver. We complement this method with user grouping, relay selection diversity and time division among the transmitting nodes in order to achieve the gains promised by network coding in terms of throughput increase, while halving the power usage at the relay nodes. We show that these complements are necessary in order to translate the decrease in the number of transmissions offered by network coding into capacity gains; otherwise, random application of network coding would provide a worse performance compared to direct transmission or decode-and-forward relaying.
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Sankerdial, Roger. "Developing a resilient green cellular network." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/39006.
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CHDS State/Local<br>As technology drives society to a ubiquitously wireless world, the paradox of mobile wireless network accessibility versus resilience is disturbingly trending in opposite directions. The demand for cellular networks with greater capacity and bandwidth appears to be the primary factor in expanding coverage nationwide, with resilience becoming a secondary thought. It is expected that resilient systems will be able to withstand shocks and stresses from critical incidents and still be able to function as intentionally designed. However, the fragility of cellular networks affected by recent disasters within the last ten years has demonstrated otherwise. The purpose of this research is to direct attention to the importance of cellular base station functionality during power outages and illustrate how these assets require modification to provide critical communications for the public to summon aid, and first responders to coordinate response efforts. Prior research offers strategies to implement post-disaster remediation supplanting failed localized communication infrastructure. This mitigating strategy requires substantial time, labor, and planning to deploy that subsequently detracts from conducting immediate response and recovery. This research is intended to propose a path forward for resiliency in U.S. mobile cellular networks using renewable/alternative energy outlined in Indias National Telecom Policy for 2012.
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Nourizadeh, Hamed. "UMTS cellular network with relaying concept." Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/844065/.
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Wideband Code Division Multiple Access (WCDMA) is one of the technologies for third generation systems. In a CDMA system, all users interfere with each others, therefore the CDMA system is interference limited. The users, who suffer from a strong shadow effect or that are far away from the BS, need more power to reach it. In this case, the users may transmit at their maximum allowed power without satisfying their Quality of Service. Therefore, this would leave some mobiles in outage and also create too much interference to the neighboring cells. One-way to counter this problem and therefore to improve the capacity is to increase the number of BSs. But this solution cannot be efficient as it significantly increases the network infrastructure cost. Alternative techniques that involve less planning and are quick to deploy appear to be more advantageous. Relaying is one of these techniques and is growing in importance for future wireless systems. In this thesis, a new radio access network based on combinations of multi-hop and star-topology architectures is proposed. The main objective of this thesis is to demonstrate achievable capacity gains under various relaying criteria compared with no-relaying (conventional) cellular architecture. In this new architecture, some intermediate nodes (mobile or fixed) located between the originating terminal and the BSs are used for the purpose of retransmitting the original packets. We show that under specific criteria and conditions the multihop concept indeed yields capacity gains. A number of different scenarios are defined and their relative performances are fully evaluated using an accurate dynamic system-level simulator. The capacity gains are compared to the case of no relaying/hopping. To demonstrate the achievable capacity gains, we use UMTS FDD and TDD modes. The proposed concepts and criteria for relaying are generic enough to be used with current and future radio access technologies. The results show that under certain conditions an uplink capacity gain of 30-40% is readily achievable with the multihop architecture.
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Åkesson, Emma. "Information visualization of network parameters in private cellular network solutions." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280858.
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In the upcoming years, industrial enterprises are expected to undergo a major transformation, as the Internet of Things (IoT) reaches widespread adoption. A key enabler behind this transformation, known as Industry 4.0, is the 5th generation of cellular networks (5G). Through privately owned networks, enterprises will be able to utilize the 5G technology to tailor the network to meet their needs in terms of security, reliability, and quality of service. Although much of the technology is currently in place, few efforts have been dedicated to help enterprises understand and optimise the value that this new solution brings. One way of making 5G more accessible is through information visualization of its data. Dashboards are today the widely adopted tool for processing data in organisations. This study aimed at examining the affordances and challenges of information visualization of 5G network data in such a tool, in order to make 5G more accessible. A large number of commercial network management dashboards were reviewed in relation to research on effective dashboard design, and a prototype was developed and evaluated with seven user experience experts. Results from the expert review suggests information visualization clearly aided communication of the five visualized network parameters: throughput, latency, availability, coverage, and devices. However, to fully examine the usefulness of the tool, further research on the tool’s fit in an industry context needs to be conducted.<br>Inom de kommande åren förväntas industriföretag genomgå en stor transformation, i samband med att sakernas internet (engelskans Internet of Things, IoT) når utbredd användning. En viktig möjliggörare bakom denna transformation, känd som Industri 4.0, är den 5:e generationens mobilnät (5G). Genom privatägda mobilnät kommer företag att kunna använda 5G teknologin till att skräddarsy sina nätverk för att tillgodose de egna behoven gällande säkerhet, tillförlitlighet och kvalitet. Trots att mycket av 5G teknologin redan är på plats, har få ansträngningar gjorts för att hjälpa företag förstå och optimera värdet som denna nya lösning medför. Ett sätt som kan göra 5G mer lättförståeligt är genom informationsvisualisering av dess data. Dashboards är idag det mest använda verktyget för att bearbeta data i organisationer. Denna studie ämnade därför att undersöka fördelarna och nackdelarna med informationsvisualisering av data från ett privat 5G-nät i ett sådant verktyg. Ett stort antal kommersiella dashboards för nätverksprestationshantering granskades i förhållande till forskning inom området för effektiv design av dashboards, och en prototyp utvecklades och utvärderades med sju experter inom användarupplevelse. Resultaten från expertgranskningen tyder på att användningen av informationsvisualisering klart hjälpte i kommunikationen av de fem visualiserade nätverksparametrarna: genomströmning, svarstid, tillgänglighet, täckning och uppkopplade enheter. Däremot krävs ytterligare forskning kring verktygets roll i industriell kontext för att kunna göra en fullständig granskning av verktygets användbarhet.
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Mugume, Edwin. "Green heterogeneous cellular networks." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/green-heterogeneous-cellular-networks(e7976a91-c891-4174-abaf-18820ff1736d).html.
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Data traffic demand has been increasing exponentially and this trend will continue over theforeseeable future. This has forced operators to upgrade and densify their mobile networks toenhance their capacity. Future networks will be characterized by a dense deployment of different kinds of base stations (BSs) in a hierarchical cellular structure. However network densification requires extensive capital and operational investment which limits operator revenues and raises ecological concerns over greenhouse gas emissions. Although networks are planned to support peak traffic, traffic demand is actually highly variable in both space and time which makes it necessary to adapt network energy consumption to inevitable variations in traffic demand. In this thesis, stochastic geometry tools are used to perform simple and tractable analysis of thecoverage, rate and energy performance of homogeneous networks and heterogeneous networks(HetNets). BSs in each tier are located according to independent Poisson Point Processes(PPPs) to generate irregular topologies that fairly resemble practical deployment topologies. The homogeneous network is optimized to determine the optimal BS density and transmit power configuration that minimizes its area power consumption (APC) subject to both coverage and average rate constraints. Results show that optimal transmit power only depends on the BSpower consumption parameters and can be predetermined. Furthermore, various sleep modemechanisms are applied to the homogeneous network to adapt its APC to changes in userdensity. A centralized strategic scheme which prioritize BSs with the least number of usersenhances energy efficiency (EE) of the network. Due to the complexity of such a centralizedscheme, a distributed scheme which implements the strategic algorithm within clusters of BSsis proposed and its performance closely matches that of its centralized counterpart. It is more challenging to model the optimal deployment configuration per tier in a multi-tier HetNet. Appropriate assumptions are used to determine tight approximations of these deployment configurations that minimize the APC of biased and unbiased HetNets subject tocoverage and rate constraints. The optimization is performed for three different user associationschemes. Similar to the homogeneous network, optimal transmit power per tier also depends onBS power consumption parameters only and can also be predetermined. Analysis of the effect of biasing on HetNet performance shows appropriate biasing can further reduce the deploymentconfiguration (and consequently the APC) compared to an unbiased HetNet. In addition, biasing can be used to offload traffic from congesting and high-power macro BSs to low-power small BSs. If idle BSs are put into sleep mode, more energy is saved and HetNet EE improves. Moreover, appropriate biasing also enhances the EE of the HetNet.
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Platt, Steven. "Decentralized cellular networks: Towards blockchain enabled cellular overlays." Doctoral thesis, Universitat Pompeu Fabra, 2021. http://hdl.handle.net/10803/672922.
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This thesis undertakes an investigation into the fit and utility of blockchain technologies within
cellular networks. The core of this writing is a new 5G core network blockchain designed to be
compatible with, and paired as storage for 3GPP-compliant virtual network functions.
Compatibility of the blockchain design is delivered by inheriting a number of behaviors from
wireless network operation, including a CSMA/CD mechanism of congestion control; a first for a
blockchain design. At the carrier level, a deployment model compatible with ETSI General
Autonomous Network Architecture is presented to enable decentralized service overlays. At the
network edge, a novel model of transition learning allows fluid roaming of user-equipment
across network boundaries. At the conclusion, the theory is combined, to reveal a model of
decentralized overlays, which at the user equipment, functions in a manner similar to FM radio.
A network channel radio of sorts for decentralized cellular access.<br>Aquesta tesi realitza una investigació sobre l’us i l’adptabilitat de les tecnologies blockchain en
xarxes cel·lulars. El nucli d’aquest treball és una nova blockchain basada en la xarxa 5G
dissenyada per ser compatible i utilitzada com a emmagatzematge per a la funció de xarxa
virtual compatible amb 3GPP. La compatibilitat del disseny de la blockchain s’ofereix adoptant
diversos comportaments de l'operació de xarxa sense fils, inclos un mecanisme CSMA/CD de
control de congestió; la primera vegada que s’utilitza per a un disseny de blockchain. A nivell de
transport, es presenta un model de desplegament compatible amb l’arquitectura general de
xarxes autonomes ETSI per permetre superposicions de serveis descentralitzats. A la capa de
xarxa, presentem un nou model de ”transition learning” que facilita una itinerància fluida de
l’equip d’usuari a través dels l ́ımits de la xarxa. Per acabar, la part teórica és combina per
revelar un model de capes superposades descentralitzades, on l’equip de l’usuari funciona de
manera similar una radio FM. Un canal de radio amb accés descentralitzat.
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Ghafari, Bamdad. "Extendable design of a cellular network simulator." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq64079.pdf.
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BONIFAZI, MAURIZIO. "Analog circuits design for cellular neural network." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/705.
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Il paradigma delle Reti Neurali Artificiali (ANN) consiste nell’applicazione del modello neurale “biologico” per la risoluzione di problemi che spesso sono troppo complessi per un’architettura di Von Neumann.
La letteratura offre differenti approcci per l’implementazione di ANN. Qualche implementazione è di tipo software, altre sono soluzioni circuitali come circuiti digitali full-custom o FPGA (Field Programmable Gate Array), come pure circuiti analogici, e il tipo di implementazione di certo dipende dal tempo di esecuzione adeguato al tipo di applicazione.
Questa tesi riguarda la progettazione di nuovi circuiti analogici adattati per le Reti Neurali. In particolare, saranno utilizzate le Reti Neurali Cellulari (CNN) proposte nel 1981 dal Prof. L.O.Chua (University of California – Berkeley). Il “Laboratorio di Circuiti” dell’Università di Roma “Tor Vergata” ha progettato e realizzato alcuni chip analogici dedicati a questo tipo di Reti Neurali. Questi chip appartengono alla famiglia “Digital Programmable CNN” (DPCNN) e presentano principalmente due caratteristiche: la programmabilità digitale dei pesi sinaptici come una particolare architettura orientata ad una struttura interconnessa (cioè connettendo tra loro più di questi chip è possibile realizzare reti di grande dimensione).
In questa tesi viene data una visione di insieme sulle ANN, sulle CNN e sulle Star-CNN: cosa sono, come funzionano ed a cosa servono. In perticolare verrà descritta la famiglia DP-CNN.
Questa tesi propone una nuova architettura chiamata TD-CNN (Time Division CNN), che sfrutta una particolare strategia mirata a ridurra l’area di occupazione su silicio di una cella elementare, per aumentare l’integrabilità della rete. Oltretutto la stessa strategia a divisione di tempo verrà applicata alle TD-Star CNN. In particolare questi circuiti sono le non-linerità digitalmente programmabili (cioè DPTA – Digital Programmable Transconductance Amplifier e DPTA – Digital Programmable Transconductance Comparator) e circuiti particolari per la multiplazione (DM-SH – Dynamic Mirror Sample and Hold e DM-MUX – Dynamic Mirror Multiplexer). Sono mostrate alcune simulazioni dei circuiti per permettere lo studio di queste nuove architetture, e la modifica delle dinamiche introdotte dalla strategia a divisione di tempo.<br>The Artificial Neural Network (ANN) paradigm consists of the application of biological “neural” models to the solution of particular problems that often are very hard to solve for the classical “Von Neumann” architectures.
Different are the approaches proposed in literature for the implementation of an ANN. Some of them are software implementations only while, others are circuital solutions as full custom digital circuits or programmed FPGAs (Field Programmable Gate Array) as well as analogue circuits and the typology of the implementation certainly depends on the length of the processing time that you believe adequate for the particular application.
This thesis is focused on the design of new analogue circuits well suited for Neural Network applications. In particular, the class of the Cellular Neural Networks (CNN), proposed in 1981 by Prof. L.O.Chua (University of California - Berkeley), will be exploited. In this area, the “Laboratorio Circuiti” at University of Rome “Tor Vergata” designed and manufactured several analogue chips devoted to this class of Neural Networks. These chips belong to the Digital Programmable CNN (DPCNN) chip family and present two main features: the digital programmability of the synaptic weights as well as a special architecture oriented to an interconnection structure (i.e. it is possible to carry out large network by connecting together more of these chips).
In this thesis work you will find an overview about the Artificial Neural Network, the Cellular Neural Network and the Star Cellular Neural Network: what they are, how they work and why they are useful. In particular, the DP-CNN chip family will be deeply described.
This thesis proposes the TD-CNN (Time Division CNN), a particular design strategy, devoted to reduce the silicon area occupation of the a elementary cell in order to improve the VLSI integrability of the network. Moreover, the same time-division strategy will be applied to TD-Star CNN. In particular, these circuits consist of the digitally programmable non-linearity circuits (i.e. the Digital Programmable Transconductance Amplifier - DPTA and Digital Programmable Transconductance Comparator – DTPC) and special circuit for to carry out the multiplexing feature (i.e. the Dynamic Mirror Sample and Hold – DM-SH and the Multiplexer – DM-MUX).
Several circuital simulations will be shown in order to study the behavior of this modified architecture and the modifications on the dynamics introduced by the time division strategy.
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Huang, Shimin. "Cross-Layer Congestion Control with Deep Neural Network in Cellular Network." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264239.
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A significant fraction of data traffic is transmitted via cellular networks. When introducing fifth-generation (5G) radio access technology, the maximum bitrate of the radio link increases significantly, and the delay is lowered. Network congestion occurs when the sender attempts to send data at a higher rate than the network link or nodes can handle. In order to improve the performance of the mobile networks, many congestion control techniques and approaches have been developed over the years. Varying radio conditions in mobile networks make it challenging to indicate the occurrence of the congestion using packet loss as congestion indicator. This master thesis develops a congestion control algorithm based on Artificial Intelligence (AI) technologies, evaluates and compares it with existing state-of-the-art congestion control algorithms that are used with TCP today.In this study, we use the abundant readable physical layer information exchanged between the base stations and the user equipment to predict the available bandwidth. Two neural network models, Multi-Layer Perceptron (MLP) and Long Short-Term Memory (LSTM), are introduced as congestion control algorithms based on cross-layer information in order to improve user throughput and utilize the available capacity as much as possible.Evaluation in a Long-Term Evolution (LTE) network system simulator confirms that the estimation of LSTM model is able to track the varying link capacity, while MLP is less accurate and induces higher delay. The sender uses the estimated link capacity to adjust its packet sending behavior. Our evaluation reveals that for large flows, the LSTM model can attain higher throughput than state-of-the-art congestion control algorithms, which are the Google Bottleneck Bandwidth and Round-trip propagation time (BBR) algorithm and the Data Center TCP (DCTCP) algorithm. However, it has higher latency than that of these two algorithms. The MLP based model provides unstable performance compared to LSTM; its prediction is not accurate enough and has the highest latency among the algorithms.In conclusion, the LSTM does not underperform the state-of-the-art congestion control algorithms. However, it does not provide additional performance gains in current settings. The MLP model underperforms BBR and DCTCP with L4S and it is not stable enough to be used as a congestion control algorithms.<br>En betydande del av datatrafiken överförs via mobilnät. Vid introduktion av femte generationens (5G) radioåtkomstteknik ökar den maximala bithastigheten för radiolänken betydligt och förseningen sänks. Nätstockning uppstår när avsändaren försöker skicka data med högre hastighet än nätverkslänken eller noderna kan hantera. För att förbättra prestandan i mobilnät har många tekniker för trängselkontroll utvecklats under åren. Varierande radioförhållanden i mobilnätet gör det utmanande att indikera förekomsten av trängseln med hjälp av paketförlust som trängselindikator. Detta examensarbete utvecklar en trängselkontrollalgoritm baserad på AI-teknik (Artificial Intelligence), utvärderar och jämför den med befintliga toppmoderna trängselkontrollalgoritmer som används med TCP idag.I denna studie använder vi den rikliga läsbara informationen om fysiskt lager som utbyts mellan basstationerna och användarutrustningen för att förutsäga den tillgängliga bandbredden. Två neurala nätverksmodeller, Multi-Layer Perceptron (MLP) och Long Short-Term Memory (LSTM), introduceras som trängselkontrollalgoritmer baserade på tvärskiktsinformation för att förbättra användarens genomströmning och utnyttja den tillgängliga kapaciteten så mycket som möjligt.Utvärdering i en LTE-nätverkssystemsimulator (Long Term Evolution) bekräftar att uppskattningen av LSTM-modellen kan spåra den varierande länkkapaciteten, medan MLP är mindre exakt och inducerar högre fördröjning. Avsändaren använder den uppskattade länkkapaciteten för att justera sitt paketets sändningsbeteende. Vår utvärdering avslöjar att för stora flöden kan LSTM-modellen uppnå högre genomströmning än modernaste trängselkontrollalgoritmer, som är Google Bottleneck Bandbredd och BBR-algoritm och Data Center TCP (DCTCP) ) algoritm. Men det har högre latens än för dessa två algoritmer. Den MLP-baserade modellen ger instabil prestanda jämfört med LSTM; dess förutsägelse är inte nog noggrann och har den högsta latensen bland algoritmerna.Sammanfattningsvis underpresterar LSTM inte de senaste toppkontrollalgoritmerna. Det ger emellertid inte ytterligare prestationsvinster i de aktuella inställningarna. MLP-modellen underpresterar BBR och DCTCP med L4S och den är inte tillräckligt stabil för att användas som en överbelastningskontrollalgoritm.
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Bousia, Alexandra. "Design of energy efficient network planning schemes for LTE-based cellular networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/386393.
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The rapid expansion of mobile services and the emerging demand for multimedia applications have led to an impressive traffic growth. To this end, Mobile Network Operators (MNOs) seek to extend their infrastructure by installing more Base Stations (BSs), in an effort to increase the network capacity and meet the pressing traffic demands. Furthermore, to fulfill the escalated demands, Heterogeneous Networks (HetNets), which consist of Small Cells (SCs) and the traditional BSs, constitute the new trend of next generation networks.
The deployed infrastructure implies a rise in the Capital Expenditures and has a direct impact on the network energy consumption, thus resulting in higher Operational Expenditures. Hence, the investigation of energy efficient solutions will bring down the energy consumption and the network cost. Since the BS is the most power hungry component, the research community has shifted towards the investigation of BS deactivation schemes. These schemes propose that part of the infrastructure can be temporarily switched off, when the traffic is low, while the active BSs extend their coverage to serve the network.
Based on a comprehensive review of the state-of-the-art, a set of research opportunities were identified. This thesis provides contributions to the field of BS switching off strategies for wireless macro BSs networks and HetNets of single and multiple MNOs by proposing mechanisms that enhance different aspects of the network performance. The BSs deactivation, the innovative trend of infrastructure sharing and the financially driven collaboration among the involved parties of the current and future networks promise significant improvements in terms of energy and cost savings. The main thesis contributions are divided into three parts, described next.
The first part of the thesis introduces innovative BS switching off approaches in single-operator environments, where only macro BSs are deployed. The proposed strategies exploit the inherit characteristics of the traffic load pattern (e.g., distribution of the users, traffic volume, etc.) and the distinctive features of the wireless cellular networks (e.g., BSs position, topology, etc.). Theoretical analysis and computer-based simulations show the performance improvement offered by the switching off strategies with respect to energy efficiency.
The second part of the thesis explores a different challenge in network planning. The coexistence of multiple MNOs in the same geographical area has motivated a new business model, known as infrastructure sharing. A roaming-based deactivation scheme is proposed, by taking into account the rationality and the conflicting interests of the MNOs. The proposed game theoretic framework enables the MNOs to take individual switching off decisions, thus bypassing potential complicated agreements. The theoretical and simulation results show that our proposal significantly improves the energy efficiency, guaranteeing at the same time the throughput in realistic scenarios. Moreover, the proposed scheme provides higher cost efficiency and fairness compared to the state-of-the-art algorithms, motivating the MNOs to adopt game theoretic strategies.
The third part of the thesis focuses on the exploitation of HetNets and the proposal of energy and cost effective strategies in SC networks with multiple MNOs. We effectively address the cost sharing by proposing accurate cost models for the SCs to share the network cost. Taking into account the impact of the traffic on the cost, we propose novel cost sharing policies that provide a fair outcome. In continuation, innovative auction-based schemes within multiobjective optimization framework are introduced for data offloading from the BSs, owned by the MNOs, to the third-party SC networks. The proposed solution captures the conflicting interests of the MNOs and the third-party companies and the obtained results show that the benefit of proposing switching off approaches for HetNets.<br>La rápida expansión de los servicios móviles y de la demanda emergente de aplicaciones multimedia han dado lugar a un impresionante crecimiento del tráfico. Operadores de redes móviles (MNOs) tratará de extender su infraestructura mediante la instalación de más estaciones base (BSs), en un esfuerzo por aumentar la capacidad de la red y satisfacer las apremiantes demandas de tráfico. Además, para cumplir con las exigencias escalada, redes heterogéneas (HetNets), constituyen la nueva tendencia de las redes de próxima generación. La infraestructura implica un aumento en los gastos de capital y tiene un impacto directo en el consumo de energía a la red, lo que resulta en un aumento de los gastos operacionales. La investigación de soluciones de eficiencia energética hará bajar el consumo de energía y el coste de la red. La comunidad científica se ha desplazado hacia la investigación de los sistemas de desactivación de BSs. Estos esquemas proponen que parte de la infraestructura se puede cdesectivarse, cuando el tráfico es bajo, mientras que los BSs activas extender su cobertura al servicio de la red. Esta tesis ofrece contribuciones al campo de la BSs desconexión para las redes y HetNets con uno o multiples MNOs, proponiendo mecanismos que mejoran diferentes aspectos del rendimiento de la red. La desactivación de BS,s la tendencia innovadora de compartir infraestructura y la colaboración impulsada financieramente entre las partes implicadas de las redes actuales y futuras prometen mejoras significativas en términos de ahorro energético y económico. Las principales contribuciones de tesis se dividen en tres partes, que se describen a continuación. La primera parte de la tesis introduce innovadora apagar enfoques en entornos de un solo operador, donde se despliegan sólo macro BSs. Las estrategias propuestas explotan las características de tráfico (por ejemplo, la distribución de los usuarios, el volumen de tráfico, etc.) y las características distintivas de las redes (por ejemplo, la posición BS, topología, etc.). Análisis teórico y simulaciones muestran la mejora del rendimiento ofrecido por las estrategias de conmutación con respecto a la eficiencia energética. La segunda parte de la tesis explora un reto diferente en la planificación de la red. La coexistencia de múltiples operadores en la misma zona geográfica ha motivado un nuevo modelo de negocio, conocida como la compartición de infraestructura. Se propone un esquema de desactivación basada en itinerancia, teniendo en cuenta la racionalidad y los intereses en conflicto de los operadores de redes móviles. Los resultados teóricos y de simulación muestran que nuestra propuesta mejora significativamente la eficiencia energética, garantizando al mismo tiempo el rendimiento en escenarios realistas. Por otra parte, el esquema propuesto proporciona una mayor eficiencia de costes y la equidad en comparación con los algoritmos del estado de la técnica, motivar al mnos de adoptar estrategias de teoría de juegos. La tercera parte de la tesis se centra en la explotación de HetNets y la propuesta de estrategias eficaces de energía y costes en las redes con múltiples operadores. Nos dirigimos efectivamente la participación en los costos, proponiendo modelos de costos precisos para para compartir el costo de la red. Teniendo en cuenta el impacto del tráfico en el coste, proponemos políticas costos compartidos novedosas que proporcionan un resultado justo. En la continuación, los esquemas basados en subastas innovadoras dentro de marco de optimización multiobjetivo se introducen los datos que descargan de la BS. La solución propuesta recoge los intereses en conflicto de los operadores de redes móviles y las compañías de terceros y los resultados obtenidos muestran que el beneficio de proponer la desconexión se acerca para HetNets
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Hvaal, Harald. "Evaluating the Influence of Network Structure on Boolean Networks and Cellular Automata." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for datateknikk og informasjonsvitenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11781.
Full textAbstract:
While there have been many papers respectively on the qualities of Boolean networks and Cellular Automata, little work has been done on comparing these networks to each other. Network parameters such as input count and choice of Boolean functions are often fixed in preparation of the experiments with less regard to what effect that choice has. In this paper a broader overview of how the choice of network structure and network parameters will affect the behavior of the network is given. Metrics such as iterations until stabilization (intermediary state count) and complexity of network behavior over time (functional complexity) are proposed, and evaluated for a set of 15 different network configurations. CA networks are observed to have much less functional complexity than BN, and in general BN seems to have more potential for complex behavior. It is also observed that for increasing values of dimension count/input count the functional complexity decreases.
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Dlamini, Thembelihle. "Core Network Management Procedures for Self-Organized and Sustainable 5G Cellular Networks." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3422837.
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This thesis investigates resource management procedures, within the Multi-access Edge Computi ng (MEC) paradigm, to obtain energy savings and guarantee Quality of Service(QoS) in Mobile Networks (MNs). Here, we enable energy savings within green-aware network apparatuses (i.e., communication and computing facilities) through the application of learning and control techniques, together with energy management procedures (BS sleep mode, VM soft-scaling, tuning of transmission drivers). In this study, we consider the MEC deployment scenarios suggested by ETSI and mobile operators for our system models.
Firstly, we investigate energy-saving strategies within a remote site fully powered by only green/renewable energy (solar and wind). Here, we consider a single Base Station (BS) co-located with the MEC server, i.e., the BS is empowered with computing capabilities. To address the energy consumption problem within the remote site, we propose an online algorithm for edge network management. The algorithm make use of a Long Short-Term Memory (LSTM) neural network for estimating the short-term future traffic load and harvested energy, and control theory, specifically the Limited Lookahead Control (LLC) principles, for foresighted optimization. It also make use of energy management procedures, i.e., BS sleep modes and Virtual Machine (VM) soft-scaling (the reduction of computing resources per time instance). To obtain the energy savings and guarantee QoS, per time instance, the algorithm considers the future BS loads, onsite green energy available and then provisions edge network resources based on the learned information.
Secondly, we study the energy consumption problem within an environment where BSs are densely-deployed, i.e., similar to an urban or semi-urban scenario. This work extend the energy consumption problem from a single BS case to multiple BSs. Here, each BS is powered by hybrid energy supplies (solar and power grid) and also empowered with computation capabilities (each BS is co-located with a MEC server). Towards edge system management, we propose a controller-based network architecture for managing energy harvesting (EH) BSs empowered with computation capabilities where on/off switching strategies allow BSs and VMs to be dynamically switched on/off, depending on the traffic load and the harvested energy forecast, over a given look-ahead prediction horizon. To solve the energy consumption minimization problem in a distributed manner, the controller partitions the BSs into clusters based on their location; then, for each cluster, it minimizes a cost function capturing the individual communication site energy consumption and the users’ QoS. To manage the communication sites, the controller performs online supervisory control by forecasting the traffic load and the harvested energy using a LSTM neural network, which is utilized within a LLC policy to obtain the system control actions that yield the desired trade-off between energy consumption and QoS.
Finally, we investigate the energy consumption problem within a virtualized MEC server placed in proximity to a group of BSs. To address this challenge, we consider a computing-plus-communication energy model, within the MEC paradigm, where we focus on the communication-related energy cost in addition to the energy drained due to computing processes. Towards server management, an online algorithm based on traffic engineering and MEC Location Service is proposed. To obtain the energy savings and QoS guarantee, we jointly launch an optimal number of VMs for computing and transmission drivers coupled with the location-aware traffic routing for real-time data transfers. In order to efficiently provisioned edge system resources, we forecast the server workloads and harvested energy by using a LSTM neural network and the output is then used within the LLC-based algorithm.
Our numerical results, obtained through trace-driven simulations, show that the proposed optimization strategies (algorithms) leads to a considerable reduction in the energy consumed by the edge computing and communication facilities, promoting energy self-sustainability within the MN through the use of green energy.
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Yassine, Daadaa. "Network Decontamination with Temporal Immunity." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20633.
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Network decontamination is a well known mobile agent problem with many applications. We assume that all nodes of a network are contaminated (e.g., by a virus) and a set of agents is deployed to decontaminate them. An agent passing by a node decontaminates it, however a decontaminated node can be recontaminated if any of its neighbours is contaminated. In the vast literature a variety of models are considered and different assumptions are made on the power of the agents.
In this thesis we study variation of the decontamination problem in mesh and tori topologies, under the assumption that when a node is decontaminated, it is immune to recontamination for a predefined amount of time t (called immunity time). After the immunity time is elapsed, recontamination can occur.
We focus on three different models: mobile agents (MA), cellular automata (CA), and mobile cellular automata (MCA). The first two models are commonly studied and employed in several other contexts, the third model is introduced in this thesis for the first time. In each model we study the temporal decontamination problem (adapted to the particular setting) under a variety of assumptions on the capabilities of the decontaminating elements (agents for MA and MCA, decontaminating cells for CA). Some of the parameters we consider in this study are: visibility of the active elements, their ability to make copies of themselves, their ability to communicate, and the possibility to remember their past actions (memory). We describe several solutions in the various scenarios and we analyze their complexity. Efficiency is evaluated slightly differently in each model, but essentially the effort is in the minimization of the number of simultaneous decontaminating elements active in the system while performing the decontamination with a given immunity time.
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Devoe, Malcom, and Malcom W. Jr Devoe. "Cellular Neural Networks with Switching Connections." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/math_theses/115.
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Artificial neural networks are widely used for parallel processing of data analysis and visual information. The most prominent example of artificial neural networks is a cellular neural network (CNN), composed from two-dimensional arrays of simple first-order dynamical systems (“cells”) that are interconnected by wires. The information, to be processed by a CNN, represents the initial state of the network, and the parallel information processing is performed by converging to one of the stable spatial equilibrium states of the multi-stable CNN. This thesis studies a specific type of CNNs designed to perform the winner-take-all function of finding the largest among the n numbers, using the network dynamics. In a wider context, this amounts to automatically detecting a target spot in the given visual picture. The research, reported in this thesis, demonstrates that the addition of fast on-off switching (blinking) connections significantly improves the functionality of winner-take-all CNNs. Numerical calculations are performed to reveal the dependence of the probability, that the CNN correctly classifies the largest number, on the switching frequency.
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Navaratnarajah, Shobanraj. "Efficient network selection schemes for an operator deployed cellular-WLAN heterogeneous network." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/813337/.
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The HetNet architecture is considered to be one of the promising solutions for the problem of capacity crunch and increasing energy consumption of wireless communication networks. Hence, it is expected to be one of the key aspects in the realisation of the future wireless communication networks. Moreover, future wireless communication networks are characterised by the co-existence of multiple radio access technologies called multi-RAT HetNets. In this context, the integrated cellular-WLAN HetNet attracts considerable interest among the mobile network operators. One of the major challenges of such HetNet is the optimal selection of serving network. In this regard, this thesis focuses on the efficient network selection schemes for an operator deployed cellular-WLAN HetNet. Firstly, a novel load balancing scheme is proposed for an operator deployed cellular-WLAN HetNet, where the user association is controlled by employing cell-breathing technique for the WLAN network. In this scheme, the coverage of each WiFi AP is dynamically optimised to achieve desired load balancing. Since this is a network controlled traffic steering scheme, users can simply associate to the available strongest WiFi AP, without making any complex network selection decisions. Thus, can be easily implemented in an existing cellular-WLAN HetNet. Subsequently, performance analysis of cellular-WLAN HetNet is carried out for a saturated downlink scenario, in order to investigate the effect of deploying CRE technique for WLAN network in the cellular-WLAN HetNet. In addition, a cellular-WLAN interworking architecture and detailed signalling procedures are proposed for implementing CRE scheme in an operator deployed cellular-WLAN HetNet. Finally, a novel Adaptive Stochastic Radio Access Selection scheme is proposed for an operator deployed cellular-WLAN HetNet. This scheme implements a stochastic network selection policy that assigns certain probability for selecting WLAN according to the status of the network in terms of load and signal quality. The proposed scheme helps to improve the system performance in terms of network throughput, energy efficiency, and call blocking probability.
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Lorenzo, Veiga B. (Beatriz). "New network paradigms for future multihop cellular systems." Doctoral thesis, Oulun yliopisto, 2012. http://urn.fi/urn:isbn:9789514298554.
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Abstract The high increase in traffic and data rate for future generations of mobile communication systems, with simultaneous requirement for reduced power consumption, makes Multihop Cellular Networks (MCNs) an attractive technology. To exploit the potentials of MCNs a number of new network paradigms are proposed in this thesis. First, a new algorithm for efficient relaying topology control is presented to jointly optimize the relaying topology, routing and scheduling resulting in a two dimensional or space time routing protocol. The algorithm is aware of intercell interference (ICI), and requires coordinated action between the cells to jointly choose the relaying topology and scheduling to minimize the system performance degradation due to ICI. This framework is extended to include the optimization of power control. Both conventional and cooperative relaying schemes are considered. In addition, a novel sequential genetic algorithm (SGA) is proposed as a heuristic approximation to reconfigure the optimum relaying topology as the network traffic changes. Network coding is used to combine the uplink and downlink transmissions, and incorporate it into the optimum bidirectional relaying with ICI awareness. Seeking for a more tractable network model to effectively use context awareness and relying on the latest results on network information theory, we apply a hexagonal tessellation for inner partition of the cell into smaller subcells of radius r. By using only one single topology control parameter (r), we jointly optimize routing, scheduling and power control to obtain the optimum trade-off between throughput, delay and power consumption in multicast MCNs. This model enables high resolution optimization and motivates the further study of network protocols for MCNs. A new concept for route discovery protocols is developed and the trade-off between cooperative diversity and spatial reuse is analyzed by using this model. Finally, a new architecture for MCN is considered where multihop transmissions are performed by a Delay Tolerant Network, and new solutions to enhance the performance of multicast applications for multimedia content delivery are presented. Numerical results have shown that the algorithms suggested in this thesis provide significant improvement with respect to the existing results, and are expected to have significant impact in the analysis and design of future cellular networks<br>Tiivistelmä Tiedonsiirron ja tiedonsiirtonopeuksien suuri kasvu sekä tehonkulutuksen pieneneminen tulevien sukupolvien matkapuhelinjärjestelmissä tekevät monihyppyiset matkapuhelinverkot houkutteleviksi vaihtoehdoiksi. Tässä työssä esitetään uusia tiedonsiirtoverkkojen paradigmoja monihyppyisten matkapuhelinverkkojen hyödyntämiseksi. Työssä esitellään uusi algoritmi tehokkaaseen releointitopologian hallintaan, joka optimoi yhtäaikaisesti topologian, reitityksen sekä lähetyshetkien ajoituksen ja mahdollistaa tila-aika-reititysprotokollan toteutuksen. Esitetty algoritmi huomioi solujen keskinäishäiriön ja vaaditulla solujen välisellä koordinoidulla hallinnalla saadaan yhdessä valittua topologia ja ajoitus, jotka minimoivat solujen keskinäisistä häiriöistä johtuvan suorituskyvyn heikentymisen. Myöhemmin tätä viitekehystä on laajennettu lisäämällä siihen tehonsäädön optimointi. Työssä on tutkittu sekä perinteisiä että kooperatiivisia releointimenetelmiä. Lisäksi työssä esitetään uusi geneettinen algoritmi heuristiseksi approksimaatioksi verkon liikenteen muutoksen vaatimaan releointitopologian uudelleen järjestelyyn. Työssä tarkastellaan lisäksi verkkokoodausta ylä- ja alasuuntaan tapahtuvan tiedonsiirron yhdistämiseksi sisällyttämällä se solujen keskinäishäiriön huomioivaan kahdensuuntaiseen releointiin. Etsittäessä paremmin mukautuvaa ja kontekstitietoisuutta hyödyntävää verkkomallia, joka käyttää hyväkseen viimeisimpiä verkkojen informaatioteoreettisia tuloksia, voidaan verkon solut pilkkoa pienempiin kuusikulmaisiin alisoluihin. Käyttämällä ainoastaan näiden alisolujen sädettä r voidaan puolestaan verkon reititys, ajoitus ja tehon säätö optimoida yhtäaikaisesti saavuttaen paras mahdollinen kompromissi verkon läpäisyn, viiveen ja tehonkulutuksen välillä. Kehitetty malli mahdollistaa korkean resoluution optimoinnin ja motivoi uusien verkkoprotokollien kehitystä monihyppyisissä matkapuhelinverkoissa. Tätä mallia käyttäen esitellään myös uusi konsepti reitinetsintäprotokollille sekä analysoidaan kooperatiivisen diversiteetin ja tila-avaruudessa tapahtuvan uudelleenkäytön välistä kompromissiratkaisua. Lopuksi työssä tarkastellaan monihyppyisen matkapuhelinverkon uutta arkkitehtuuria, jossa monihyppylähetykset suoritetaan viivesietoisella verkolla ja esitetään uusia ratkaisuja multimediasisällön monilähetysten tehokkuuden parantamiseksi. Työssä saadut tulokset osoittavat, että ehdotetut algoritmit parantavat järjestelmien suorituskykyä verrattuna aiemmin tiedossa olleisiin tuloksiin. Työn tuloksilla voidaan olettaa myös olevan suuri vaikutus tulevaisuuden matkapuhelinverkkojen analysointiin ja suunnitteluun
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Mathew, Anu. "VLSI library cells for Cellular Neural Network applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0009/MQ52470.pdf.
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Avramescu, Sinziana. "Cellular and homeostatic network mechanisms of posttraumatic epilepsy." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25580/25580.pdf.
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Suite aux traumatismes crâniens pénétrants, le cerveau devient graduellement hyperexcitable et génère des activités paroxystiques spontanées. Les mécanismes qui sous-tendent l’épileptogénèse demeurent cependant peu connus. La ligne directrice de nos travaux consiste en l'hypothèse que la diminution de l'activité corticale engendrée par la déafférentation déclenche des mécanismes homéostatiques agissant tant au niveau cellulaire qu’au niveau du réseau cortical, et qui mènent à une excitabilité neuronale accrue culminant en crises d’épilepsie.
Nous avons testé cette hypothèse chez des chats adultes, lors de différents états de vigilance ou sous anesthésie, ayant subits une déafférentation partielle du gyrus suprasylvien. Nous avons évalué les effets de la déafférentation corticale aigue et chronique sur la survie des neurones et des cellules gliales et nous avons investigué comment la privation chronique d'afférences neuronales pourrait modifier les propriétés du réseau cortical et déclencher des crises d’épilepsie.
Après la déafférentation du gyrus suprasylvien, les neurones situés dans les couches corticales profondes, en particulier les neurones inhibiteurs GABAérgiques, dégénèrent progressivement et parallèlement à une fréquence croissante des activités paroxystiques, notamment pendant le sommeil à ondes lentes. La privation chronique d'afférences neuronales et la perte de neurones activent les mécanismes homéostatiques de plasticité qui favorisent une plus grande connectivité neuronale, une efficacité plus élevée des connexions synaptiques excitatrices et des changements des propriétés neuronales intrinsèques. Ensemble, ces facteurs favorisent une excitation accrue du réseau cortical. L'activité corticale spontanée, mesurée par les taux moyens de décharge, augmente progressivement, en particulier pendant le sommeil à ondes lentes, caractérisé par des périodes silencieuses alternant avec des périodes actives. Ceci soutient, en outre, notre hypothèse concernant la participation des mécanismes de plasticité homéostatique. La dégénération des neurones des couches corticales profondes produit des changements importants dans la distribution laminaire de l'activité neuronale, qui est déplacée vers les couches plus superficielles, dans la partie déafferenté du gyrus. Ce changement dans la distribution de profils de profondeurs de décharges neuronales modifie également le déclenchement de l'activité corticale spontanée. Dans le cortex normal et dans la partie relativement intacte du gyrus suprasylvien, l'activité corticale est générée dans les couches corticales profondes. Pourtant, dans le cortex chroniquement déafferenté, l'oscillation lente et les activités ictales sont générées dans les couches superficielles et puis diffusent vers les couches plus profondes. Le traumatisme cortical induit également une importante gliose réactive et une altération de la fonction normale des cellules gliales, ce qui cause l’enlèvement dysfonctionnel du K+ extracellulaire et qui augmente l'excitabilité des neurones favorisant ainsi la génération d’activités paroxystiques.
En conclusion, les mécanismes de plasticité homéostatique déclenchés par le niveau diminué d'activité dans le cortex déafferenté produisent une hyperexcitabilité corticale incontrôlable et génèrent finalement les crises d’épilepsie. Dans ces conditions, l’augmentation de l'activité corticale plutôt que la diminution avec des médicaments antiépileptiques pourrait être salutaire pour empêcher le développement de l'épileptogenèse post-traumatique.<br>After penetrating cortical wounds, the brain becomes gradually hyperexcitable and generates spontaneous paroxysmal activity, but the progressive mechanisms of epileptogenesis remain virtually unknown. The guiding line of our experiments was the hypothesis that the reduced cortical activity following deafferentation triggers homeostatic mechanisms acting at cellular and network levels, leading to an increased neuronal excitability and finally generating paroxysmal activities.
We tested this hypothesis either in anesthetized adult cats, or during natural sleep and wake, using the model of partially deafferented suprasylvian gyrus to induce posttraumatic epileptogenesis. We evaluated the effects of acute and chronic cortical deafferentation on the survival of neurons and glial cells and how long-term input deprivation could shape up the properties of neuronal networks and the initiation of spontaneous cortical activity.
Following cortical deafferentation of the suprasylvian gyrus, the deeply laying neurons, particularly the inhibitory GABAergic ones, degenerate progressively in parallel with an increased propensity to paroxysmal activity, mainly during slow-wave sleep. The chronic input deprivation and the death of neurons activate homeostatic plasticity mechanisms, which promote a gradual increased neuronal connectivity, higher efficacy of excitatory synaptic connections and changes in intrinsic cellular properties favoring increased excitation. The spontaneous cortical activity quantified by means of firing rate augments also progressively, particularly during slow-wave sleep, characterized by periods of silent states alternating with periods of active states, which supports furthermore our hypothesis regarding the involvement of homeostatic plasticity mechanisms. The degeneration of neurons in the deep cortical layers generates important changes in the laminar distribution of neuronal activity, which is shifted from the deeper layers to the more superficial ones, in the partially deafferented part of the gyrus. This change in the depth profile distribution of firing rates modifies also the initiation of spontaneous cortical activity which, in normal cortex, and in the relatively intact part of the deafferented gyrus, is initiated in the deep cortical layers. Conversely, in late stages of the undercut, both the cortical slow oscillation and the ictal activity are initiated in the more superficial layers and then spread to the deeper ones. Cortical trauma induces also an important reactive gliosis associated with an impaired function of glial cells, responsible for a dysfunctional K+ clearance in the injured cortex, which additionally increases the excitability of neurons, promoting the generation of paroxysmal activity.
We conclude, that the homeostatic plasticity mechanisms triggered by the decreased level of activity in the deafferented cortex, generate an uncontrollable cortical hyperexcitability, finally leading to seizures. If this statement is true, augmenting cortical activity rapidly after cortical trauma rather than decreasing it with antiepileptic medication, could prove beneficial in preventing the development of posttraumatic epileptogenesis.<br>Inscrite au Tableau d'honneur de la Faculté des études supérieures
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Yap, Jung Houn. "Locating services in hybrid ad hoc cellular network." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/623/.
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Wallentinsson, Emma Wallentinsson. "Multiple Time Series Forecasting of Cellular Network Traffic." Thesis, Linköpings universitet, Statistik och maskininlärning, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-154868.
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The mobile traffic in cellular networks is increasing in a steady rate as we go intoa future where we are connected to the internet practically all the time in one wayor another. To map the mobile traffic and the volume pressure on the base stationduring different time periods, it is useful to have the ability to predict the trafficvolumes within cellular networks. The data in this work consists of 4G cellular trafficdata spanning over a 7 day coherent period, collected from cells in a moderately largecity. The proposed method in this work is ARIMA modeling, in both original formand with an extension where the coefficients of the ARIMA model are re-esimated byintroducing some user characteristic variables. The re-estimated coefficients produceslightly lower forecast errors in general than a isolated ARIMA model where thevolume forecasts only depends on time. This implies that the forecasts can besomewhat improved when we allow the influence of these variables to be a part ofthe model, and not only the time series itself.
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Agbogidi, Oghenetega. "Practical Evaluation of a Software Defined Cellular Network." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984175/.
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This thesis proposes a design of a rapidly deployable cellular network prototype that provides voice and data communications and it is interoperable with legacy devices and the existing network infrastructure. The prototype is based on software defined radio and makes use of IEEE 802.11 unlicensed wireless radio frequency (RF) band for backhaul link and an open source GSM implementation software. The prototype is also evaluated in environments where there is limited control of the radio frequency landscape, and using Voice Over Internet Protocol (VoIP) performance metrics to measure the quality of service. It is observed that in environments where the IEEE 802.11 band is not heavily utilized, a large number of calls are supported with good quality of service. However, when this band is heavily utilized only a few calls can be supported as the quality of service rapidly degrades with increasing number of calls, which is due to interference. It is concluded that in order to achieve tolerable voice quality, unused licensed spectrum is needed for backhaul communication between base stations.
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Khan, Aroba. "Network Modeling in Heterogeneous and Cooperative Cellular Communications." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15436.
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The rapid increase in use of smart phones and devices has introduced a growing demand in data traffic which the conventional homogeneous macro cells can no longer satisfy. A promising solution to this is by spectrum reuse through deploying various low-power small cells overlaid on the macro cell. This represents the heterogeneous cellular network that we see today. The change from homogeneous to heterogeneous environment requires new cellular network models to be developed. This thesis presents various novel approaches and models for both homogeneous and heterogeneous cellular networks. Cellular network models aim to provide insights into the performance of the network and its users. One of the most important metrics of network performance and user experience is the signal-to interference- plus-noise-ratio, or SINR. A network operator wanting to optimize the performance of a heterogeneous network needs to know the spatial distribution of the SINR. So, researchers need to carefully consider the network parameters and their spatial distributions while modeling cellular networks. Besides having low-power base stations deployed in hot spot regions, cooperative communication can also be used to improve user performance by reducing the effect of path loss and fading. Considering these facts, the proposed research considers the inclusion of cooperation while modeling cellular networks. Under the proposed scheme, a user in low coverage can use a nearby low-power base station via cooperation to communicate with the macro base station. The main contributions of this thesis can be summarized as below: • A simplified linear cellular network model is proposed which considers the average user distance to determine user performance under a uniform user distribution scenario. This model simplifies the linear grid based model while improving the conventional Wyner model with fading. The proposal is extended to incorporate Gaussian based non-uniform distribution of users within macro cells. The effect of cooperation on user performance is also included in the proposed model where a cell boundary user can use a nearby low-power base station as relay. Mathematical models for analytically evaluating both downlink and uplink transmissions are developed in a multi-cell scenario. The user distributions of interfering neighboring cells are also taken into account. • A two-dimensional heterogeneous cellular network model is developed which considers a realistic spatial distribution of both macro and low-power base stations. For avoiding the probability of severe interference caused by Poisson point process distributed macro base stations, the proposed model considers a grid based distribution for macro base stations and a random distribution for the low-power base stations. Cooperative communication is included in the proposed model where the low-power base stations can act as relays for macro users that are in low coverage. Mathematical models for analytically evaluating user outage and coverage performance is formulated. • A large number of the total cellular network users today are vehicular, i.e. traveling in public transports while using cellular connectivity. The signal strength inside vehicles are attenuated by vehicle penetration loss and hence, becomes weak. To solve this issue, recently researchers have proposed the use of moving relays (MRs) which are mounted on top of public transportation vehicles. However, the impact of having MRs in current heterogeneous cellular networks is not yet investigated. A network model is proposed which considers the presence of MRs on top of suburban trains and derives coverage performance of both vehicular and non-vehicular users for downlink. The effect of MRs in the overall network performance is also evaluated. • Cellular network modeling for uplink is generally known to be difficult since both signal and interference become user location dependent. Moreover, due to power control the transmission power of users varies across cell locations which complicate the analysis to a greater extent. A heterogeneous network model is proposed for uplink with the presence of MRs on suburban trains. Per-user fractional power control is considered and both vehicular and non-vehicular user outage performance is derived. • Cooperative communication via MRs is also included in the proposed heterogeneous network models for both uplink and downlink. According to the proposal, a train traveling in the macro cell with a MR mounted on top can be used as a relay for nearby non-vehicular users in low coverage. Different traveling directions for the train within macro cells are considered and the effect of cooperation via MR on user performance is analyzed for each case. Extensive simulations are carried out for evaluating network performance, which demonstrate the capability of the proposed models in substantially enhancing the performance. The performance evaluation is established with the inclusion of cooperation and MRs in the proposed heterogeneous cellular network models.
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Breyer, Nils. "Analysis of Travel Patterns from Cellular Network Data." Licentiate thesis, Linköpings universitet, Kommunikations- och transportsystem, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157139.
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Traffic planners are facing a big challenge with an increasing demand for mobility and a need to drastically reduce the environmental impacts of the transportation system at the same time. The transportation system therefore needs to become more efficient, which requires a good understanding about the actual travel patterns. Data from travel surveys and traffic counts is expensive to collect and gives only limited insights on travel patterns. Cellular network data collected in the mobile operators infrastructure is a promising data source which can provide new ways of obtaining information relevant for traffic analysis. It can provide large-scale observations of travel patterns independent of the travel mode used and can be updated easier than other data sources. In order to use cellular network data for traffic analysis it needs to be filtered and processed in a way that preserves privacy of individuals and takes the low resolution of the data in space and time into account. The research of finding appropriate algorithms is ongoing and while substantial progress has been achieved, there is a still a large potential for better algorithms and ways to evaluate them. The aim of this thesis is to analyse the potential and limitations of using cellular network data for traffic analysis. In the three papers included in the thesis, contributions are made to the trip extraction, travel demand and route inference steps part of a data-driven traffic analysis processing chain. To analyse the performance of the proposed algorithms, a number of datasets from different cellular network operators are used. The results obtained using different algorithms are compared to each other as well as to other available data sources. A main finding presented in this thesis is that large-scale cellular network data can be used in particular to infer travel demand. In a study of data for the municipality of Norrköping, the results from cellular network data resemble the travel demand model currently used by the municipality, while adding more details such as time profiles which are currently not available to traffic planners. However, it is found that all later traffic analysis results from cellular network data can differ to a large extend based on the choice of algorithm used for the first steps of data filtering and trip extraction. Particular difficulties occur with the detection of short trips (less than 2km) with a possible under-representation of these trips affecting the subsequent traffic analysis.
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Chobineh, Amirreza. "Influence of new network architectures and usages on RF human exposure in cellular networks." Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT019.
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Dans les années à venir, le trafic de données dans les réseaux cellulaires connaîtra une forte croissance en raison de l'augmentation de l’utilisation des moyens de télécommunications sans fil. Par conséquent, les opérateurs de réseaux mobiles visent à augmenter la capacité et la couverture de leurs réseaux afin de répondre à cette croissance. Dans ce contexte, l'un des principaux efforts est de densifier les réseaux Macrocells actuels par les Small cells afin d’offrir plus de couverture et de débit aux utilisateurs. Les antennes Small cells émettent de faibles puissances et sont souvent déployées à de faibles hauteurs. En conséquence, ils sont plus proches des utilisateurs, peuvent être déployés massivement mais génèrent également des inquiétudes chez les riverains. Les téléphones portables sont utilisés pour une grande variété d'utilisations qui nécessitent différentes quantités de données et de débit. Les applications de voix sur IP telles que Skype sont devenues très populaires car elles fournissent une communication vocale internationale peu onéreuse et peuvent être utilisées sur les appareils mobiles. Étant donné que les systèmes LTE ne prennent en charge que les services par paquets, le service vocal utilise la technologie voix sur LTE au lieu de la technologie « circuits » classique comme avec le GSM et UMTS.L'objectif principal de cette thèse est d'évaluer l'influence des nouvelles architectures des réseaux et usages sur l'exposition actuel du publique induite par les réseaux cellulaires. À cet égard, plusieurs campagnes de mesures ont été menées dans différentes villes et environnements.En ce qui concerne l'exposition aux champs électromagnétiques dans les réseaux hétérogènes, les résultats suggèrent qu'en déployant les Small cells, la puissance émise par le téléphone mobile, en raison de la proximité de l’antenne et par conséquent l’exposition global diminue. De plus, pour évaluer l'exposition EMF des utilisateurs indoor induite par les Small cells, deux modèles statistiques sont proposés pour les expositions montante et descendante induite dans un réseau hétérogène LTE.La dernière partie de cette thèse est consacrée à l'évaluation de l'exposition aux nouveaux types d'usages. Les résultats suggèrent que la puissance émise et la durée d'émission par un téléphone mobile dépendent fortement de l’usage et de la technologie du réseau. Les communications voix nécessitent un débit continu et généralement faible afin de maintenir la communication pendant l'appel. Au contraire, dans le cas de l’usage données, le téléphone mobile nécessite des débits plus élevés pour effectuer la tâche le plus rapidement. Par conséquent, pendant un appel voix, même si l'utilisateur utilise le téléphone portable pendant une durée relativement longue, la durée de l'exposition est moins longue car l'utilisation ne nécessite pas une grande quantité de données. Ainsi, le taux d'occupation temporelle de plusieurs types d'appels voix pour différentes technologies est évalué par les mesures<br>In coming years, there will be a sharp growth in wireless data traffic due to the increasing usage of mobile phones and implementation of IoT technology. Therefore, mobile network operators aim to increase the capacity of their networks, to provide higher data traffic with lower latency, and to support thousands of connections. One of the primary efforts toward these goals is to densify today's cellular Macrocell networks using Small cells to bring more coverage and higher network capacity. Small cell antennas emit lower power than Macrocells and are often deployed at low heights. As a consequence, they are closer to the user and can be implemented massively. The latter can result in an important raise in public concerns. Mobile phones are used on the one hand, for a large variety of data usages that require different amounts of data and throughput and on the other hand for making phone calls. Voice over IP applications such as Skype has become very popular since they provide cheap international voice communication and can be used on mobile devices. Since LTE systems only support packet services, the voice service uses Voice over LTE technology instead of classical circuit-switched voice technology as in GSM and UMTS. The main objective of this thesis is to characterize and analyse the influence of new network architectures and usages on the actual human exposure induced by cellular networks. In this regard, several measurement campaigns were carried out in various cities and environments. Regarding the EMF exposure in heterogeneous networks, results suggest that by implementing Small cells, the global exposure (i.e. exposure induced by mobile phone and base station antenna) reduces due to the fact that by bringing the antenna closer to the user the emitted power by mobile phone and the usage duration reduce owing to power control schemes implemented in cellular network technologies. However, the magnitude of exposure reduction depends on the location of the Small cell with respect to Macrocells. Moreover, to assess the EMF exposure of indoor users induced by Small cells, two statistical models are proposed for the uplink and downlink exposures in an LTE heterogeneous environment based on measurements. The last part of the thesis was devoted to the assessment of the exposure for new types of usages through measurements. Results suggest that the amount of uplink emitted power and the emission time duration by a mobile phone is highly dependent on the usage and network technology. Voice call communications require a continuous and generally low throughput in order to maintain the communication during the call. On the contrary, in data usage, the mobile phone requires higher data and throughput to perform the task as fast as possible. Therefore during a voice call even if the user is using the mobile phone for a relatively long time, the exposure time duration should be lower since the usage does not require high amounts of data. The temporal occupation rate for several types of voice calls for different technologies is assessed through measurements
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Zhao, Xiwei. "Foundational Forensic Techniques for Cellular and Ad Hoc Multi-hop Networks." FIU Digital Commons, 2008. http://digitalcommons.fiu.edu/etd/23.
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The Internet has become an integral part of our nation's critical socio-economic infrastructure. With its heightened use and growing complexity however, organizations are at greater risk of cyber crimes. To aid in the investigation of crimes committed on or via the Internet, a network forensics analysis tool pulls together needed digital evidence. It provides a platform for performing deep network analysis by capturing, recording and analyzing network events to find out the source of a security attack or other information security incidents. Existing network forensics work has been mostly focused on the Internet and fixed networks. But the exponential growth and use of wireless technologies, coupled with their unprecedented characteristics, necessitates the development of new network forensic analysis tools. This dissertation fostered the emergence of a new research field in cellular and ad-hoc network forensics. It was one of the first works to identify this problem and offer fundamental techniques and tools that laid the groundwork for future research. In particular, it introduced novel methods to record network incidents and report logged incidents. For recording incidents, location is considered essential to documenting network incidents. However, in network topology spaces, location cannot be measured due to absence of a 'distance metric'. Therefore, a novel solution was proposed to label locations of nodes within network topology spaces, and then to authenticate the identity of nodes in ad hoc environments. For reporting logged incidents, a novel technique based on Distributed Hash Tables (DHT) was adopted. Although the direct use of DHTs for reporting logged incidents would result in an uncontrollably recursive traffic, a new mechanism was introduced that overcome this recursive process. These logging and reporting techniques aided forensics over cellular and ad-hoc networks, which in turn increased their ability to track and trace attacks to their source. These techniques were a starting point for further research and development that would result in equipping future ad hoc networks with forensic components to complement existing security mechanisms.
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Jacobson, Olof. "Correlating Local Weather Conditions with Cellular Network Performance Indicators." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189600.
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In this thesis, the relationships between local weather and the performance of a cellular telecommunications network were investigated by means of data analysis. Models of the average daily cycles in the data were developed accounting for cyclic behaviour and seasonal trends. Several different analysis methods were then performed on data measuring deviations from these average cycles. The methods used were multiple linear regression, partial least squares regression, calculation of Spearman's correlation coefficients, and regression by artificial neural networks. Some of the results indicate that the number of calls being attempted in the network is related to the local weather conditions. Additionally, small indications were found that the percentage of failed calls in the network was related to the amount of precipitation. These findings could potentially be valuable for network operators.<br>I detta examensarbete undersöktes samband mellan lokala väderförhållanden och indikatorer på nätverksprestanda för ett mobilnätverk. Undersökningen genomfördes med hjälp av dataanalys. Modeller för den genomsnittliga dagliga variationen i de undersökta parametrarna utvecklades där hänsyn togs till cykliska trender och säsongsberoende. Ett flertal analysmetoder tillämpades sedan på data som mätte avvikelser från de genomsnittliga variationerna. Metoderna som användes var linjär regression, ’partial least squares’ regression, uträkning av Spearmans rangkorrelation, och regression med hjälp av artificiella neuronnät. Resultaten indikerade att antalet samtal som försökte kopplas upp i nätverket influerades av väderförhållandena. Dessutom kunde små indikationer urskiljas på att nederbörd påverkade andelen misslyckade samtalsuppkopplingar i nätverket. Resultaten kan potentiellt vara av värde för nätverksoperatörer.
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Cheung, Hing Keung. "Modelling, design and implementation of a flexible cellular network." Thesis, King's College London (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417009.
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Du, Toit Riaan. "The applications of superconductors in cellular network base stations." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/20433.
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Thesis (MScIng)--University of Stellenbosch, 2008.<br>ENGLISH ABSTRACT: The Applications of Superconductors in Cellular Network Base
Stations
R. Du Toit
Department of Electronic Engineering
University of Stellenbosch
Private Bag X1, 7602 Matieland, South Africa
Thesis: MScEng (E&E)
March 2008
Wireless communications have increasingly become part of our world. The growth of radio
frequency (RF) wireless communications has led to an increasing demand for frequency
spectrum licenses, increased system capacity and larger user bandwidths. These demands
lead to frequent improvements on the physical and higher layers of wireless communication
protocols. Changes in the physical layer are frequently followed by the need for replacement
of dedicated hardware components. The need therefore exists for a more general
and programmable physical layer. A more general and programmable radio architecture
implies increased radio front-end performance without losing programmability.
The contribution of this thesis is the analysis of how superconductor electronics (SCE)
using Rapid Single Flux Quantum (RSFQ) logic may advance wireless radio front-ends
by providing a general-purpose programmable radio architecture. Superconductor analogue
to digital converters (ADCs) are employed as high performance, programmable
digitization structures. Once a received signal is digitized, SCE can be used to rapidly
do recursive operations such as synchronization and multi-path delay estimation. These
operations are based on correlation, and for evaluation of such operations with SCE the
popular CDMA multiplexing method is studied along with the WCDMA protocol used
in the 3G UMTS standard.
Two delta-type oversampling superconductor ADC modulator designs are presented
and evaluated along with a hybrid decimation filter design, using both the benefits of SCE and room temperature electronics. A fast RSFQ correlator design is also presented
and evaluated for use in a multi-path estimation structure. A rapid multi-path delay
estimation architecture based on fast RSFQ circular data buffers and correlators is presented.
The architecture uses the fast speeds of RSFQ logic to obtain accurate path delay
estimates in a rapidly changing wireless environment.
It is concluded that RSFQ-based wireless receiver components offer promising new
options for data conversion, correlation and multi-path delay estimation implementations.<br>AFRIKAANSE OPSOMMING: The Applications of Superconductors in Cellular Network Base
Stations
R. Du Toit
Department of Electronic Engineering
University of Stellenbosch
Private Bag X1, 7602 Matieland, South Africa
Thesis: MScEng (E&E)
March 2008
Draadlose kommunikasie word al hoe meer deel van ons wêreld. Groei in radiofrekwensietipe
kommunikasie het gelei tot ’n toenemende aanvraag na frekwensiespektrum lisensies,
vergrote stelselkapasiteit en groter gebruikerbandwydtes. Hierdie aanvrae lei tot gereelde
en spoedige verbeteringe op die fisiese en hoër lae van huidige draadlose kommunikasieprotokol.
Veranderinge in die fisiese laag vereis gewoonlik dat toegewyde hardewarde komponente
vervang word. Die behoefte bestaan dus vir ’n meer algemene, programmeerbare
fisiese laag. Dit vereis dus ’n verbetering in die radio-ontvanger se komponente naaste
aan die antenna sonder om programmeerbaarheid te verloor.
Die bydrae van hierdie tesis is hoofsaaklik die analise van hoe supergeleierelektronika
wat van Rapid Single Flux Quantum (RSFQ) logika gebruik maak, huidige draadlose
sellulêre basisstasies se fisiese laag kan verbeter deur ’n meer algemene en programmeerbare
radio-argitektuur op te lewer. Supergeleier analoog-na-syfer omsetters (ADCs) word
bestudeer as moontlike programmeerbare versyferingstrukture wat steeds hoë werkverrigting
lewer. Wanneer ’n ontvangde sein in digitale vorm omgesit is, kan supergeleierelektronika
gebruik word om vinnig rekursiewe operasies uit te voer. Voorbeelde van sulke
operasies is sinkronisasie en die waardebepaling van die vertraging van verskillende paaie
wat ’n sein volg na die ontvanger. Hierdie spesifieke operasies se werking is gebaseer op korrelasie,
en vir die evaluasie van sulke operasies met supergeleierelektronika is die gewilde wyeband-CDMA (WCDMA) protokol wat gebruik word in die 3G UMTS-standaard.
Twee supergeleier-delta-tipe oorversyferings-ADC-moduleerderontwerpe word voorgelê
en evaluasie word daarop gedoen saam met ’n hibriede desimasiefilterontwerp wat gebruik
maak van beide die voordele van supergeleierelektronika en kamertemperatuurelektronika.
’n Vinnige RSFQ-korreleerder word ook voorgelê en evaluasie word daarop gedoen
vir gebruik binne ’n multi-padvertraging-waardebepalerstruktuur. Hierdie struktuur wat
gebaseer is op RSFQ sirkulêre buffers en korreleerders, word voorgelê. Die waardebepaler
maak gebruik van die spoed van RSFQ-logika om akkurate multi-padvertragingswaardes
te bepaal in ’n vinnig veranderende draadlose omgewing.
Die gevolgtrekking word gemaak dat RSFQ-gebaseerde draadlose ontvangerkomponente
groot voordele in versyfering-, korreleerder- en multi-padvertragingsbepaler-toepassings
bied.
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Arcand, Simon Carleton University Dissertation Engineering Systems and Computer. "Load sharing in an integrated satellite - terrestrial cellular network." Ottawa, 1995.
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Asgari, Fereshteh. "Inferring user multimodal trajectories from cellular network metadata in metropolitan areas." Thesis, Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0005/document.
Full textAbstract:
Dans cette thèse, nous avons étudier une méthode de classification et d'évaluation des modalités de transport utilisées par les porteurs de mobile durant leurs trajets quotidiens. Les informations de mobilité sont collectées par un opérateur au travers des logs du réseau téléphonique mobile qui fournissent des informations sur les stations de base qui ont été utilisées par un mobile durant son trajet. Les signaux (appels/SMS/3G/4G) émis par les téléphones sont une source d'information pertinente pour l'analyse de la mobilité humaine, mais au-delà de ça, ces données représentent surtout un moyen de caractériser les habitudes et les comportements humains. Bien que l'analyse des metadata permette d'acquérir des informations spatio-temporelles à une échelle sans précédent, ces données présentent aussi de nombreuses problématiques à traiter afin d'en extraire une information pertinente. Notre objectif dans cette thèse est de proposer une solution au problème de déduire la trajectoire réelle sur des réseaux de transport à partir d'observations de position obtenues grâce à l'analyse de la signalisation sur les réseaux cellulaires. Nous proposons « CT-Mapper" pour projecter les données de signalisation cellulaires recueillies auprès de smartphone sur le réseau de transport multimodal. Notre algorithme utilise un modèle de Markov caché et les propriétés topologiques des différentes couches de transport. Ensuite, nous proposons « LCT-Mapper » un algorithme qui permet de déduire le mode de transport utilisé. Pour évaluer nos algorithmes, nous avons reconstruit les réseaux de transport de Paris et de la région (Ile-de-France). Puis nous avons collecté un jeu de données de trajectoires réelles recueillies auprès d'un groupe de volontaires pendant une période de 1 mois. Les données de signalisation cellulaire de l'utilisateur ont été fournies par un opérateur français pour évaluer les performances de nos algorithmes à l'aide de données GPS. Pour conclure, nous avons montré dans ce travail qu'il est possible d'en déduire la trajectoire multimodale des utilisateurs d'une manière non supervisée. Notre réalisation permet d'étudier le comportement de mobilité multimodale de personnes et d'explorer et de contrôler le flux de la population sur le réseau de transport multicouche<br>Around half of the world population is living in cities where different transportation networks are cooperating together to provide some efficient transportation facilities for individuals. To improve the performance of the multimodal transportation network it is crucial to monitor and analyze the multimodal trajectories, however obtaining the multimodal mobility data is not a trivial task. GPS data with fine accuracy, is extremely expensive to collect; Additionally, GPS is not available in tunnels and underground. Recently, thanks to telecommunication advancement cellular dataset such as Call Data Records (CDRs), is a great resource of mobility data, nevertheless, this kind of dataset is noisy and sparse in time. Our objective in this thesis is to propose a solution to this challenging issue of inferring real trajectory and transportation layer from wholly cellular observation. To achieve these objectives, we use Cellular signalization data which is more frequent than CDRs and despite their spatial inaccuracy, they provide a fair source of multimodal trajectory data. We propose 'CT-Mapper’ to map cellular signalization data collected from smart phones over the multimodal transportation network. Our proposed algorithm uses Hidden Markov Model property and topological properties of different transportation layers to model an unsupervised mapping algorithm which maps sparse cellular trajectories on multilayer transportation network. Later on, we propose ‘LCT-Mapper’ an algorithm to infer the main mode of trajectories. The area of study in this research work is Paris and region (Ile-de-France); we have modeled and built the multimodal transportation network database. To evaluate our proposed algorithm, we use real trajectories data sets collected from a group of volunteers for a period of 1 month. The user's cellular signalization data was provided by a french operator to assess the performance of our proposed algorithms using GPS data as ground truth. An extensive set of evaluation has been performed to validate the proposed algorithms. To summarize, we have shown in this work that it is feasible to infer the multimodal trajectory of users in an unsupervised manner. Our achievement makes it possible to investigate the multimodal mobility behavior of people and explore and monitor the population flow over multilayer transportation network
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Hossain, Md Farhad. "Traffic-Driven Energy Efficient Operational Mechanisms in Cellular Access Networks." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10084.
Full textAbstract:
Recent explosive growth in mobile data traffic is increasing energy consumption in cellular networks at an incredible rate. Moreover, as a direct result of the conventional static network provisioning approach, a significant amount of electrical energy is being wasted in the existing networks. Therefore, in recent time, the issue of designing energy efficient cellular networks has drawn significant attention, which is also the foremost motivation behind this research. The proposed research is particularly focused on the design of self-organizing type traffic-sensitive dynamic network reconfiguring mechanisms for energy efficiency in cellular systems. Under the proposed techniques, radio access networks (RANs) are adaptively reconfigured using less equipment leading to reduced energy utilization. Several energy efficient cellular network frameworks by employing inter-base station (BS) cooperation in RANs are proposed. Under these frameworks, based on the instantaneous traffic demand, BSs are dynamically switched between active and sleep modes by redistributing traffic among them and thus, energy savings is achieved. The focus is then extended to exploiting the availability of multiple cellular networks for extracting energy savings through inter-RAN cooperation. Mathematical models for both of these single-RAN and multi-RAN cooperation mechanisms are also formulated. An alternative energy saving technique using dynamic sectorization (DS) under which some of the sectors in the underutilized BSs are turned into sleep mode is also proposed. Algorithms for both the distributed and the centralized implementations are developed. Finally, a two-dimensional energy efficient network provisioning mechanism is proposed by jointly applying both the DS and the dynamic BS switching. Extensive simulations are carried out, which demonstrate the capability of the proposed mechanisms in substantially enhancing the energy efficiency of cellular networks.
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Asgari, Fereshteh. "Inferring user multimodal trajectories from cellular network metadata in metropolitan areas." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0005.
Full textAbstract:
Dans cette thèse, nous avons étudier une méthode de classification et d'évaluation des modalités de transport utilisées par les porteurs de mobile durant leurs trajets quotidiens. Les informations de mobilité sont collectées par un opérateur au travers des logs du réseau téléphonique mobile qui fournissent des informations sur les stations de base qui ont été utilisées par un mobile durant son trajet. Les signaux (appels/SMS/3G/4G) émis par les téléphones sont une source d'information pertinente pour l'analyse de la mobilité humaine, mais au-delà de ça, ces données représentent surtout un moyen de caractériser les habitudes et les comportements humains. Bien que l'analyse des metadata permette d'acquérir des informations spatio-temporelles à une échelle sans précédent, ces données présentent aussi de nombreuses problématiques à traiter afin d'en extraire une information pertinente. Notre objectif dans cette thèse est de proposer une solution au problème de déduire la trajectoire réelle sur des réseaux de transport à partir d'observations de position obtenues grâce à l'analyse de la signalisation sur les réseaux cellulaires. Nous proposons « CT-Mapper" pour projecter les données de signalisation cellulaires recueillies auprès de smartphone sur le réseau de transport multimodal. Notre algorithme utilise un modèle de Markov caché et les propriétés topologiques des différentes couches de transport. Ensuite, nous proposons « LCT-Mapper » un algorithme qui permet de déduire le mode de transport utilisé. Pour évaluer nos algorithmes, nous avons reconstruit les réseaux de transport de Paris et de la région (Ile-de-France). Puis nous avons collecté un jeu de données de trajectoires réelles recueillies auprès d'un groupe de volontaires pendant une période de 1 mois. Les données de signalisation cellulaire de l'utilisateur ont été fournies par un opérateur français pour évaluer les performances de nos algorithmes à l'aide de données GPS. Pour conclure, nous avons montré dans ce travail qu'il est possible d'en déduire la trajectoire multimodale des utilisateurs d'une manière non supervisée. Notre réalisation permet d'étudier le comportement de mobilité multimodale de personnes et d'explorer et de contrôler le flux de la population sur le réseau de transport multicouche<br>Around half of the world population is living in cities where different transportation networks are cooperating together to provide some efficient transportation facilities for individuals. To improve the performance of the multimodal transportation network it is crucial to monitor and analyze the multimodal trajectories, however obtaining the multimodal mobility data is not a trivial task. GPS data with fine accuracy, is extremely expensive to collect; Additionally, GPS is not available in tunnels and underground. Recently, thanks to telecommunication advancement cellular dataset such as Call Data Records (CDRs), is a great resource of mobility data, nevertheless, this kind of dataset is noisy and sparse in time. Our objective in this thesis is to propose a solution to this challenging issue of inferring real trajectory and transportation layer from wholly cellular observation. To achieve these objectives, we use Cellular signalization data which is more frequent than CDRs and despite their spatial inaccuracy, they provide a fair source of multimodal trajectory data. We propose 'CT-Mapper’ to map cellular signalization data collected from smart phones over the multimodal transportation network. Our proposed algorithm uses Hidden Markov Model property and topological properties of different transportation layers to model an unsupervised mapping algorithm which maps sparse cellular trajectories on multilayer transportation network. Later on, we propose ‘LCT-Mapper’ an algorithm to infer the main mode of trajectories. The area of study in this research work is Paris and region (Ile-de-France); we have modeled and built the multimodal transportation network database. To evaluate our proposed algorithm, we use real trajectories data sets collected from a group of volunteers for a period of 1 month. The user's cellular signalization data was provided by a french operator to assess the performance of our proposed algorithms using GPS data as ground truth. An extensive set of evaluation has been performed to validate the proposed algorithms. To summarize, we have shown in this work that it is feasible to infer the multimodal trajectory of users in an unsupervised manner. Our achievement makes it possible to investigate the multimodal mobility behavior of people and explore and monitor the population flow over multilayer transportation network
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Hossen, Md Sazzad. "Traffic Steering in SDN Based Cellular Networks." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20878.
Full textAbstract:
To handle the increased traffic demands on cellular networks, ultra-dense and heterogeneous deployments are required. The natural evolution of the existing cellular networks will lead towards the multi-tier structure of overlapping coverage and heterogeneous resources pool. The spatial-temporal traffic dynamics and non-uniformity of traffic cause inefficient utilization of radio resources and energy. A strong desire of finding the way to make an optimal use of diverse network resources while providing satisfactory services to the users which has shifted the interest of researchers towards traffic steering in heterogeneous cellular networks. The concept of traffic steering, which intelligently redistributes traffic across the network entities, and designs optimal management schemes for the heterogeneous networks. The steering technique requires real-time network and user state information for taking the steering decisions which can be achieved by the promising software defined networking (SDN) platform. The idea of integrating SDN concept in cellular networks has gained much interest due to its up-to-date global view, logically centralized but physically distributed architecture, and programmability. In this thesis, various aspects of traffic steering technique and literature review on the integration of SDN in cellular network is presented. The key benefits and challenges of SDN integration in cellular network are briefly described in terms of network architecture design and management. A complete traffic steering framework for SDN based cellular network is proposed by considering both user’s and network current status. Finally, a traffic steering scheme is introduced which maximize network radio resource utilizations by redistributing the user’s traffic to the optimal destination. A comprehensive system level simulation has been conducted to represent the effectiveness of the proposed scheme.
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Lissai, Gidon. "Assisted GPS solution in cellular networks /." Online version of thesis, 2007. http://hdl.handle.net/1850/3671.
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TAVAKOLI, SANIJ MOHAMAD. "Uplink CoMP Capability Improvements In Heterogeneous Cellular Networks." Doctoral thesis, Politecnico di Torino, 2016. http://hdl.handle.net/11583/2644436.
Full textAbstract:
LTE-Advanced meets the challenge raised by powerful, mobile devices and bandwidth-hungry applications by investing in solutions such as carrier aggregation, higher order MIMO, relay nodes and Coordinated Multipoint (CoMP) transmission/reception. The latter, in particular, is envisioned to be one of the most important techniques in LTE-Advanced to improve the throughput and functionality of cell borders. CoMP allows users to have multiple data transmission and reception from/toward multiple cooperating eNodeBs (eNBs), increasing the utilization factor of the network. Resource allocation in the uplink is especially beneficial because more sophisticated algorithms can leverage the availability of additional connection points where the signal from the User Equipment (UE) is processed, ultimately providing UEs with increased throughput. Additionally, a significant part of the interference caused by neighboring cells can be seen as a useful received signal thanks to CoMP, provided those cells are part of the Coordinated Reception Point (CRP) set. This is especially important in critical regions, in terms of interference, like cell edges. Finally, in the case of joint multi-cell scheduling, CoMP introduces a reduction in the backhaul load by requiring only scheduling data to be transferred between coordinated eNBs.
Arguably, CoMP is most appealing in the uplink direction since it does not require UE modifications: indeed, users need not be aware that there is any kind of cooperation among receiving eNBs. UEs are merely scheduled for transmission on a set of frequencies that happens to be split among different eNBs, although they still retain standard signaling channels through only one of these eNBs, usually referred to as the serving cell.
In this work we focus on uplink CoMP from a system point of view. Specifically, we are interested in comparing through simulation the performance of uplink CoMP in various scenarios with different user participation to CoMP transmissions and CoMP margins. Some works have already investigated uplink CoMP both in simulation and through field trials. Our contribution confirms the findings of previous works as far as the throughput gain for edge users is concerned, but introduces three novel observations that can spur future investigations on CoMP systems, in both downlink and uplink regime, and lead to the design of new resource allocation algorithms:
• We look at Heterogeneous scenario where there is no restriction in the type of cells that can be in the CRP set, but simultaneously we introduce clustering option included limited number of Macro and small cells to be acted independently from other clusters in CoMP process.
• We introduce a parameter called CoMP Pool Percentage (CPP), which quantifies the fraction of PRBs that are reserved for UEs using a specific eNB as CRP (out of the resources nominally available to that eNB). Our algorithm show that the setting of CPP must be carefully gauged depending on the number of CoMP users and the scenario.
• We proposed an innovative dynamic algorithm to make decision of the CPP value in order to improve the gain for CoMP users while considering the whole network gain.
Combination of the three above mentioned routine and algorithms, according to simulations, confirms an average gain of at least 20% percent for the CoMP users, (average over various population) locating in cell boarder, while the whole network benefits by average of 5% gain for all the users (see results section). The algorithm also guarantees more gain for more values of CoMP margin. In other words, the more the population of CoMP users locating in cell borders the more would be the achievable gain.
Objectives of this PhD thesis are concluded as follows:
• Design a Network-level simulator whose features are close to a real LTE network, including advanced capabilities and innovations
• Observe the response of the network to parameters changes
• Increase the throughput gain (using CoMP vs. non using it) and the quality of service
• Design and evaluate the Novel Scheduling Algorithm
• Compare the obtained results with real cases
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Lam, Chong Lai Joshua 1977. "Interference analysis in cellular network using log shifted gamma approximation." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81545.
Full textAbstract:
Co-channel interference is the main source that limits the performance in a cellular network. Accurate interference estimation is useful for resource allocation, network planning and performance assessment in cellular systems. If the individual interference power caused by a single interferer can be approximated by a lognormal distribution due to the predominant effect of shadowing, evaluation of the total interference distribution boils down to the problem of the sum of lognormal distributed random variables. However, the problem of the sum of independent lognormal distributions is well known to be difficult due to the non-existence of closed form expressions. Many approximation methods have been proposed to solve this problem. This thesis presents the Log Shifted Gamma (LSG) approximation method, which provides high accuracy for the entire sum of lognormal distributions with all combinations of individual lognormal parameters. The probability density function (PDF) of Log Shifted Gamma random variable is in closed-form expression and is fully characterized by its parameters. By comparing results in outage probability and capacity evaluation, guideline of resource allocation, and typical value estimation, LSG approximation is found to be a better tool of analysis with higher accuracy than other methods, including the classical lognormal and Gaussian approximation.
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Ali, Syed Zahid. "A mathematical programming approach to cellular mobile radio network design." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269005.
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Hung, Keng-Shen. "Study of an intelligent camera using a cellular neural network." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339711.
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Brown, Robert L. "Application of Cellular Automata to Detection of Malicious Network Packets." NSUWorks, 2014. http://nsuworks.nova.edu/gscis_etd/106.
Full textAbstract:
A problem in computer security is identification of attack signatures in network packets. An attack signature is a pattern of bits that characterizes a particular attack. Because there are many kinds of attacks, there are potentially many attack signatures. Furthermore, attackers may seek to avoid detection by altering the attack mechanism so that the bit pattern presented differs from the known signature. Thus, recognizing attack signatures is a problem in approximate string matching. The time to perform an approximate string match depends upon the length of the string and the number of patterns. For constant string length, the time to matchnpatterns is approximatelyO(n); the time increases approximately linearly as the number of patterns increases.
A binary cellular automaton is a discrete, deterministic system of cells in which each cell can have one of two values. Cellular automata have the property that the next state of each cell can be evaluated independently of the others. If there is a processing element for each cell, the next states of all cells in a cellular automaton can be computed simultaneously.
Because there is no programming paradigm for cellular automata, cellular automata to perform specific functions are createdad hocby hand or discovered using search methods such as genetic algorithms.
This research has identified, through evolution by genetic algorithm, cellular automata that can perform approximate string matching for more than one pattern while operating in constant time with respect to the number of patterns, and in the presence of noise. Patterns were recognized by using the bits of a network packet payload as the initial state of a cellular automaton. After a predetermined number of cycles, the ones density of the cellular automaton was computed. Packets for which the ones density was below an experimentally determined threshold were identified as target packets. Six different cellular automaton rules were tested against a corpus of 7.2 million TCP packets in the IDEval data set. No rule produced false negative results, and false positive results were acceptably low.
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Keane, Harriet. "Network pharmacology of the MPP+ cellular model of Parkinson's disease." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:1e18e521-c1a3-4f1b-9572-9c68e0f16c2f.
Full textAbstract:
Parkinson's disease (PD) is an incurable neurodegenerative motor disorder caused by the inexorable loss of dopamine neurones from the substantia nigra pars compacta. Cell loss is characterised by the perturbation of multiple physiological processes (including mitochondrial function, autophagy and dopamine homeostasis) and much of this pathophysiology can be reproduced in vitro using the mitochondrial toxin MPP+ (1-methyl-4-phenylpyridinium). It was hypothesised that MPP+ toxicity could be modelled using protein-protein interaction networks (PPIN) in order to better understand the interplay of systems-level processes that result in eventual cell death in MPP+ models and PD. Initially, MPP+ toxicity was characterised in the human, dopamine-producing cell line BE(2)-M17 and it was confirmed that the neurotoxin resulted in time and dose dependent apoptosis. A radio-label pulse-chase assay was developed and demonstrated that MPP+ induced decreased autophagic flux preceded cell death. Autophagic dysfunction was consistent with lysosome deacidification due to cellular ATP depletion. Pertinent PPINs were sampled from publically available data using a seedlist of proteins with validated roles in MPP+ toxicity. These PPINs were subjected to a series of analyses to identify potential therapeutic targets. Two topological methods based on betweenness centrality were used to identify target proteins predicted to be critical for the crosstalk between mitochondrial dysfunction and autophagy in the context of MPP+ toxicity. Combined knockdown of a subset of target proteins potentiated MPP+ toxicity and the combined resulted in cellular rescue. Neither of these effects was observed following single knockdown/overexpression confirming the need for multiple interventions. Cellular rescue occurred via an autophagic mechanism; prominent autophagosomes were formed and it was hypothesised that these structures allowed for the sequestration of damaged proteins. This thesis demonstrates the value of PPINs as a model for Parkinson's disease, from network creation through target identification to phenotypic benefit.
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Dalal, Avani. "Interference Analysis and Mitigation in a Cellular Network with Femtocells." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1313756831.
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Yu, Lei. "Adaptive predictive handoff scheme with channel borrowing in cellular network." ScholarWorks@UNO, 2003. http://louisdl.louislibraries.org/u?/NOD,55.
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Thesis (M.S.)--University of New Orleans, 2003.<br>Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Computer Science"--Thesis t.p. Vita. Includes bibliographical references.
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(11184387), Amit Kumar Sheoran. "Towards a Traffic-aware Cloud-native Cellular Core." Thesis, 2021.
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<div>Advances in virtualization technologies have revolutionized the design of the core of cellular networks. However, the adoption of microservice design patterns and migration of services from purpose-built hardware to virtualized hardware has adversely affected the delivery of latency-sensitive services.</div><div><br></div><div>In this dissertation, we make a case for cloud-native (microservice container packaged) network functions in the cellular core by proposing domain knowledge-driven, traffic-aware, orchestration frameworks to make network placement decisions. We begin by evaluating the suitability of virtualization technologies for the cellular core and demonstrating that container-driven deployments can significantly outperform other virtualization technologies such as Virtual Machines for control and data plane applications.</div><div><br></div><div>To support the deployment of latency-sensitive applications on virtualized hardware, we propose using Virtual Network Function (VNF) bundles (aggregates) to handle transactions. Specifically, we design Invenio to leverage a combination of network traces and domain knowledge to identify VNFs involved in processing a specific transaction, which are then collocated by a traffic-aware orchestrator. By ensuring that a user request is processed by a single aggregate of collocated VNFs, Invenio can significantly reduce end-to-end latencies and improve user experience.</div><div><br></div><div>Finally, to understand the challenges in using container-driven deployments in real-world applications, we develop and evaluate a novel caller-ID spoofing detection solution in Voice over LTE (VoLTE) calls. Our proposed solution, NASCENT, cross validates the caller-ID used during voice-call signaling with a previously authenticated caller-ID to detect caller-ID spoofing. Our evaluation with traditional and container-driven deployments shows that container-driven deployment can not only support complex cellular services but also outperform traditional deployments.</div><div><br></div>
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Ban, Jung-Chao, and 班榮超. "Spatial Entropy in Cellular Neural Network." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/58371207608505094613.
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博士<br>國立交通大學<br>應用數學系<br>89<br>We separate this paper into two parts,in the first one,we discuss the variation of entropy with respecte to the bios-term,and from the first one,it motivates us to consider the entropy of such maps that we put a gap around the critical point symmetrically. Generally,we consider the map is unimodal map,and we get the result of open and dense entropy in the second part of this paper.