Rozprawy doktorskie: „Heterogeneous Radio Network”

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Yao, Yong. "A Software Framework for Prioritized Spectrum Access in Heterogeneous Cognitive Radio Networks". Doctoral thesis, Blekinge Tekniska Högskola [bth.se], Faculty of Computing - Department of Communication Systems, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00590.

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Today, the radio spectrum is rarely fully utilized. This problem is valid in more domains, e.g., time, frequency and geographical location. To provide an efficient utilization of the radio spectrum, the Cognitive Radio Networks (CRNs) have been advanced. The key idea is to open up the licensed spectrum to unlicensed users, thus allowing them to use the so-called spectrum opportunities as long as they do not harmfully interfere with licensed users. An important focus is laid on the limitation of previously reported research efforts, which is due to the limited consideration of the problem of competition among unlicensed users for spectrum access in heterogeneous CRNs. A software framework is introduced, which is called PRioritized Opportunistic spectrum Access System (PROAS). In PROAS, the heterogeneity aspects of CRNs are specifically expressed in terms of cross-layer design and various wireless technologies. By considering factors like ease of implementation and efficiency of control, PROAS provides priority scheduling based solutions to alleviate the competition problem of unlicensed users in heterogenous CRNs. The advanced solutions include theoretical models, numerical analysis and experimental simulations for performance evaluation. By using PROAS, three particular CRN models are studied, which are based on ad-hoc, mesh-network and cellular-network technologies. The reported results show that PROAS has the ability to bridge the gap between research results and the practical implementation of CRNs.

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Liu, Xiaoshan. "Mobility and radio resource management in heterogeneous wireless networks". Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38233873.

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Liu, Xiaoshan, i 劉曉杉. "Mobility and radio resource management in heterogeneous wireless networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38233873.

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Awoyemi, Babatunde Seun. "Resource allocation optimisation in heterogeneous cognitive radio networks". Thesis, University of Pretoria, 2017. http://hdl.handle.net/2263/61327.

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Cognitive radio networks (CRN) have been tipped as one of the most promising paradigms for next generation wireless communication, due primarily to its huge promise of mitigating the spectrum scarcity challenge. To help achieve this promise, CRN develop mechanisms that permit spectrum spaces to be allocated to, and used by more than one user, either simultaneously or opportunistically, under certain preconditions. However, because of various limitations associated with CRN, spectrum and other resources available for use in CRN are usually very scarce. Developing appropriate models that can efficiently utilise the scarce resources in a manner that is fair, among its numerous and diverse users, is required in order to achieve the utmost for CRN. 'Resource allocation (RA) in CRN' describes how such models can be developed and analysed. In developing appropriate RA models for CRN, factors that can limit the realisation of optimal solutions have to be identified and addressed; otherwise, the promised improvement in spectrum/resource utilisation would be seriously undermined. In this thesis, by a careful examination of relevant literature, the most critical limitations to RA optimisation in CRN are identified and studied, and appropriate solution models that address such limitations are investigated and proffered. One such problem, identified as a potential limitation to achieving optimality in its RA solutions, is the problem of heterogeneity in CRN. Although it is indeed the more realistic consideration, introducing heterogeneity into RA in CRN exacerbates the complex nature of RA problems. In the study, three broad classifications of heterogeneity, applicable to CRN, are identified; heterogeneous networks, channels and users. RA models that incorporate these heterogeneous considerations are then developed and analysed. By studying their structures, the complex RA problems are smartly reformulated as integer linear programming problems and solved using classical optimisation. This smart move makes it possible to achieve optimality in the RA solutions for heterogeneous CRN. Another serious limitation to achieving optimality in RA for CRN is the strictness in the level of permissible interference to the primary users (PUs) due to the activities of the secondary users (SUs). To mitigate this problem, the concept of cooperative diversity is investigated and employed. In the cooperative model, the SUs, by assisting each other in relaying their data, reduce their level of interference to PUs significantly, thus achieving greater results in the RA solutions. Furthermore, an iterative-based heuristic is developed that solves the RA optimisation problem timeously and efficiently, thereby minimising network complexity. Although results obtained from the heuristic are only suboptimal, the gains in terms of reduction in computations and time make the idea worthwhile, especially when considering large networks. The final problem identified and addressed is the limiting effect of long waiting time (delay) on the RA and overall productivity of CRN. To address this problem, queueing theory is investigated and employed. The queueing model developed and analysed helps to improve both the blocking probability as well as the system throughput, thus achieving significant improvement in the RA solutions for CRN. Since RA is an essential pivot on which the CRN's productivity revolves, this thesis, by providing viable solutions to the most debilitating problems in RA for CRN, stands out as an indispensable contribution to helping CRN realise its much-proclaimed promises.
Thesis (PhD)--University of Pretoria, 2017.
Electrical, Electronic and Computer Engineering
PhD
Unrestricted

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Boldrini, Stefano. "Cognitive radio for coexistence of heterogeneous wireless networks". Thesis, Supélec, 2014. http://www.theses.fr/2014SUPL0012/document.

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Dans un scénario avec plusieurs réseaux sans fil de différentes technologies, ce travail a comme objectif la conception d'un moteur cognitif capable de reconnaitre l'environnement radio et de sélectionner un réseau avec le but final de maximiser la "qualité d'expérience" (QoE) de l'utilisateur. Un accent particulier est mis sur la simplicité de tous les éléments impliqués, du hardware aux algorithmes, afin de garder la faisabilité pratique de ce dispositif.Deux aspects ont été étudiés. Pour la reconnaissance de l'environnement radio une identification de réseau et une classification automatique sur la base de caractéristiques de la couche MAC a été proposée et testée. En ce qui concerne la sélection du réseau, des "Key Performance Indicators" (KPIs), qui sont des paramètres de la couche application, ont étés pris en compte afin d'obtenir la QoE désirée. Un modèle général pour la sélection du réseau a été proposé et testé avec de différents types de trafic par des simulations et par la réalisation d'un démonstrateur (application pour Android). De plus, comme il y a le problème de quand mesurer pour estimer la performance d'un réseau et quand l'utiliser effectivement pour transmettre et recevoir, le problème du bandit manchot ("Multi-armed bandit", MAB) a été appliqué à ce contexte et un nouveau modèle de MAB a été proposé afin de mieux répondre aux cas réels considérés. L'impact du nouveau modèle, qui introduit la distinction de deux actions différentes, mesurer et utiliser, a été testé par des simulations en utilisant des algorithmes déjà disponibles dans la littérature et deux algorithmes conçus spécifiquement
In a scenario where multiple wireless networks of different technologies are available, this work addresses the problem of the design of a cognitive engine, core of a cognitive radio device, able to perform the surrounding radio environment recognition and the network selection with the final goal of maximization of final user Quality of Experience (QoE). Particular focus is put on the requirement of simplicity of all the elements involved, from hardware to algorithms, in order to keep in mind the importance of its practical realizability.Two aspects were investigated. For the surrounding radio environment recognition step, a network identification and automatic classification method based on MAC layer features was proposed and tested. As regards the network selection, Key Performance Indicators (KPIs), i.e. application layer parameters, were considered in order to obtain the desired goal of QoE. A general model for network selection was proposed and tested for different traffic types, both with simulations and a practical realization of a demonstrator (implemented as an application for Android OS). Moreover, as a consequence of the originated problem of when measuring to estimate a network performance and when effectively using the network for data transmission and reception purposes, the multi-armed bandit problem (MAB) was applied to this context and a new MAB model was proposed, in order to better fit the considered real cases scenarios. The impact of the new model, that introduces the distinction of two different actions, to measure and to use, was tested through simulations using algorithms already available in literature and two specifically designed algorithms

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Boldrini, Stefano. "Cognitive radio for coexistence of heterogeneous wireless networks". Doctoral thesis, Supélec, 2014. http://hdl.handle.net/11573/917817.

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Hahn, Sören [Verfasser]. "Mobile Radio Network Management in the Context of Realistic Heterogeneous Scenarios / Sören Hahn". Aachen : Shaker, 2017. http://d-nb.info/1149272163/34.

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Luo, Weizhi. "An intelligent radio access network selection and optimisation system in heterogeneous communication environments". Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/544.

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The overlapping of the different wireless network technologies creates heterogeneous communication environments. Future mobile communication system considers the technological and operational services of heterogeneous communication environments. Based on its packet switched core, the access to future mobile communication system will not be restricted to the mobile cellular networks but may be via other wireless or even wired technologies. Such universal access can enable service convergence, joint resource management, and adaptive quality of service. However, in order to realise the universal access, there are still many pending challenges to solve. One of them is the selection of the most appropriate radio access network. Previous work on the network selection has concentrated on serving the requesting user, but the existing users and the consumption of the network resources were not the main focus. Such network selection decision might only be able to benefit a limited number of users while the satisfaction levels of some users are compromised, and the network resources might be consumed in an ineffective way. Solutions are needed to handle the radio access network selection in a manner that both of the satisfaction levels of all users and the network resource consumption are considered. This thesis proposes an intelligent radio access network selection and optimisation system. The work in this thesis includes the proposal of an architecture for the radio access network selection and optimisation system and the creation of novel adaptive algorithms that are employed by the network selection system. The proposed algorithms solve the limitations of previous work and adaptively optimise network resource consumption and implement different policies to cope with different scenarios, network conditions, and aims of operators. Furthermore, this thesis also presents novel network resource availability evaluation models. The proposed models study the physical principles of the considered radio access network and avoid employing assumptions which are too stringent abstractions of real network scenarios. They enable the implementation of call level simulations for the comparison and evaluation of the performance of the network selection and optimisation algorithms.

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Rubio, Pedro, i Jesus Alvarez. "Smart Radio Control System (For Flight Test Centers)". International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596398.

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ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV
Among the rich infrastructure of a Telemetry/Ground Station Center dwells the subset dedicated to radio communications. Radios are mainly used to communicate with the aircraft under test in order to give guidance and feedback from ground specialists. Sometimes, however, radios themselves become the subject of the test, requiring a full set of them with all their features and capabilities (Military Modes, HF ALE, SELCAL, etc). Remote control (and audio routing) of these radios is a critical as infrastructures scale over tens of radios, distributed amid different test centers separated by hundreds of kilometers. Addition of a remote touch user interface, MIL COMSEC and TRANSEC modes, automatic audio routing, together with a maintenance free requirement, makes the whole issue far more difficult to manage. Airbus Defense & Space has developed a Smart Radio Control System allowing to profit from those advantages and more benefits: *Intuitive Touch UI *Automatic Audio Routing *Distributed infrastructure (network based) *Autonomous and service free (no one, other than FTC needed to operate it) *Heterogeneous (any radio can be controlled by creating a plug & play library) *Special Modes support (COMSEC, TRANSEC, HF ALE, and SELCAL) Future additions will include, amongst others, VoIP integration and tablet use.

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Ben, slimen Yosra. "Knowledge extraction from huge volume of heterogeneous data for an automated radio network management". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE2046.

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En vue d’aider les opérateurs mobiles avec la gestion de leurs réseaux d’accès radio, trois modèles sont proposés. Le premier modèle est une approche supervisée pour une prévention des anomalies. Son objectif est de détecter les dysfonctionnements futurs d’un ensemble de cellules en observant les indicateurs clés de performance considérés comme des données fonctionnelles. Par conséquent, en alertant les ingénieurs et les réseaux auto-organisés, les opérateurs mobiles peuvent être sauvés d’une dégradation de performance de leurs réseaux. Le modèle a prouvé son efficacité avec une application sur données réelles qui vise à détecter la dégradation de capacité, les problèmes d’accessibilités et les coupures d’appel dans des réseaux LTE.A cause de la diversité des technologies mobiles, le volume de données qui doivent être quotidiennement observées par les opérateurs mobiles devient énorme. Ce grand volume a devenu un obstacle pour la gestion des réseaux mobiles. Le second modèle vise à fournir une représentation simplifiée des indicateurs clés de performance pour une analyse plus facile. Du coup, un modèle de classification croisée pour données fonctionnelles est proposé. L’algorithme est basé sur un modèle de blocs latents dont chaque courbe est identifiée par ses composantes principales fonctionnelles. Ces dernières sont modélisées par une distribution Gaussienne dont les paramètres sont spécifiques à chaque bloc. Les paramètres sont estimés par un algorithme EM stochastique avec un échantillonnage de Gibbs. Ce modèle est le premier modèle de classification croisée pour données fonctionnelles et il a prouvé son efficacité sur des données simulées et aussi sur une application réelle qui vise à aider dans l’optimisation de la topologie des réseaux mobiles 4G.Le troisième modèle vise à résumer l’information issue des indicateurs clés de performance et aussi des alarmes réseaux. Un modèle de classification croisée des données mixtes : fonctionnelles et binaires est alors proposé. L’approche est basé sur un modèle de blocs latents et trois algorithmes sont comparés pour son inférence : EM stochastique avec un échantillonneur de Gibbs, EM de classification et EM variationnelle. Le modèle proposé est le premier algorithme de classification croisée pour données fonctionnelles et binaires. Il a prouvé son efficacité sur des données simulées et sur des données réelles extraites à partir de plusieurs réseaux mobiles 4G
In order to help the mobile operators with the management of their radio access networks, three models are proposed. The first model is a supervised approach for mobile anomalies prevention. Its objective is to detect future malfunctions of a set of cells, by only observing key performance indicators (KPIs) that are considered as functional data. Thus, by alerting the engineers as well as self-organizing networks, mobile operators can be saved from a certain performance degradation. The model has proven its efficiency with an application on real data that aims to detect capacity degradation, accessibility and call drops anomalies for LTE networks.Due to the diversity of mobile network technologies, the volume of data that has to be observed by mobile operators in a daily basis became enormous. This huge volume became an obstacle to mobile networks management. The second model aims to provide a simplified representation of KPIs for an easier analysis. Hence, a model-based co-clustering algorithm for functional data is proposed. The algorithm relies on the latent block model in which each curve is identified by its functional principal components that are modeled by a multivariate Gaussian distribution whose parameters are block-specific. These latter are estimated by a stochastic EM algorithm embedding a Gibbs sampling. This model is the first co-clustering approach for functional data and it has proven its efficiency on simulated data and on a real data application that helps to optimize the topology of 4G mobile networks.The third model aims to resume the information of data issued from KPIs and also alarms. A model-based co-clustering algorithm for mixed data, functional and binary, is therefore proposed. The approach relies on the latent block model, and three algorithms are compared for its inference: stochastic EM within Gibbs sampling, classification EM and variational EM. The proposed model is the first co-clustering algorithm for mixed data that deals with functional and binary features. It has proven its efficiency on simulated data and on real data extracted from live 4G mobile networks

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McAbee, Carson C. "Software-defined radio global system for mobile communications transmitter development for heterogeneous network vulnerability testing". Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/38978.

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Approved for public release; distribution is unlimited.
The conversion from homogeneous global system for mobile communications (GSM) networks to heterogeneous GSM/universal mobile telecommunications system (UMTS) networks is rapidly expanding. Previous research identified vulnerabilities in the GSM network that were fixed in the UMTS standard; however, the mobile device must successfully access the UMTS network to take advantage of security improvements. Therefore, a possible vulnerability not addressed in either the GSM or UMTS standards is the potential for a malicious entity to prevent a mobile device from handing over from a GSM to UMTS network, because the GSM network maintains the stand-alone dedicated control channel (SDCCH) uplink time slots. The process of testing this vulnerability requires the development of a device that monitors a GSM base transceiver station, identifies when a handover to UMTS message is sent, tracks the time slots of the SDCCH uplink, and transmits a GSM handover-failure message. In this thesis, we present an open-source coding scheme that utilizes parts of the OpenBTS source code to transmit a GSM handover-failure message using the universal software radio peripheral. The method is validated through the collection of the GSM transmitter messages by Airprobes GSM-receiver software.

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Shinde, Swapnil Sadashiv. "Radio Access Network Function Placement Algorithms in an Edge Computing Enabled C-RAN with Heterogeneous Slices Demands". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20063/.

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Network slicing provides a scalable and flexible solution for resource allocation with performance guaranty and isolation from other services in the 5G architecture. 5G has to handle several active use cases with different requirements. The single solution to satisfy all the extreme requirements requires overspecifies and high-cost network architecture. Further, to fulfill the diverse requirements, each service will require different resources from a radio access network (RAN), edge, and central offices of 5G architecture and hence various deployment options. Network function virtualization allocates radio access network (RAN) functions in different nodes. URLLC services require function placement nearer to the ran to fulfill the lower latency requirement while eMBB require cloud access for implementation. Therefore arbitrary allocation of network function for different services is not possible. We aim to developed algorithms to find service-based placement for RAN functions in a multitenant environment with heterogeneous demands. We considered three generic classes of slices of eMBB, URLLC, mMTC. Every slice is characterized by some specific requirements, while the nodes and the links are resources constrained. The function placement problem corresponds to minimize the overall cost of allocating the different functions to the different nodes organized in layers for respecting the requirements of the given slices. Specifically, we proposed three algorithms based on the normalized preference associated with each slice on different layers of RAN architecture. The maximum preference algorithm places the functions on the most preferred position defined in the preference matrix. On the other hand, the proposed modified preference algorithm provides solutions by keeping track of the availability of computational resources and latency requirements of different services. We also used the Exhaustive Search Method for solving a function allocation problem.

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Deng, Yansha. "Joint spatial and spectrum cooperation in wireless network". Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8926.

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The sky-rocketing growth of multimedia infotainment applications and broadband-hungry mobile devices exacerbate the stringent demand for ultra high data rate and more spectrum resources. Along with it, the unbalanced temporal and geographical variations of spectrum usage further inspires those spectral-efficient networks, namely, cognitive radio and heterogeneous cellular networks (HCNs). This thesis focuses on the system design and performance enhancement of cognitive radio (CR) and HCNs. Three different aspects of performance improvement are considered, including link reliability of cognitive radio networks (CNs), security enhancement of CNs, and energy efficiency improvement of CNs and HCNs. First, generalized selection combining (GSC) is proposed as an effective receiver design for interference reduction and reliability improvement of CNs with outdated CSI. A uni- ed way for deriving the distribution of received signal-to-noise ratio (SNR) is developed in underlay spectrum sharing networks subject to interference from the primary trans- mitter (PU-Tx) to the secondary receiver (SU-Rx), maximum transmit power constraint at the secondary transmitter (SU-Tx), and peak interference power constraint at the PU receiver (PU-Rx), is developed. Second, transmit antenna selection with receive generalized selection combining (TAS/GSC) in multi-antenna relay-aided communica- tion is introduced in CNs under Rayleigh fading and Nakagami-m fading. Based on newly derived complex statistical properties of channel power gain of TAS/GSC, exact ergodic capacity and high SNR ergodic capacity are derived over Nakagami-m fading. Third, beamforming and arti cial noise generation (BF&AN) is introduced as a robust scheme to enhance the secure transmission of large-scale spectrum sharing networks with multiple randomly located eavesdroppers (Eves) modeled as homogeneous Poisson Point Process (PPP). Stochastic geometry is applied to model and analyze the impact of i BF&AN on this complex network. Optimal power allocation factor for BF&AN which maximizes the average secrecy rate is further studied under the outage probability con- straint of primary network. Fourth, a new wireless energy harvesting protocol is proposed for underlay cognitive relay networks with the energy-constrained SU-Txs. Exact and asymptotic outage probability, delay-sensitive throughput, and delay-tolerant through- put are derived to explore the tradeoff between the energy harvested from the PU-Txs and the interference caused by the PU-Txs. Fifth, a harvest-then-transmit protocol is proposed in K-tier HCNs with randomly located multiple-antenna base stations (BSs) and single antenna mobile terminals (MTs) modeled as homogeneous PPP. The average received power at MT, the uplink (UL) outage probability, and the UL average ergodic rate are derived to demonstrate the intrinsic relationship between the energy harvested from BSs in the downlink (DL) and the MT performance in the UL. Throughout the thesis, it is shown that link reliability, secrecy performance, and energy efficiency of CNs and HCNs can be signi cantly leveraged by taking advantage of multiple antennas, relays, and wireless energy harvesting.

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Hahn, Sören [Verfasser], i Thomas [Akademischer Betreuer] Kürner. "Mobile Radio Network Management in the Context of Realistic Heterogeneous Scenarios / Sören Hahn ; Betreuer: Thomas Kürner". Braunschweig : Technische Universität Braunschweig, 2017. http://d-nb.info/1175816744/34.

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Jin, Xin. "Resource allocation in multicarrier cognitive radio networks". Thesis, Evry, Institut national des télécommunications, 2014. http://www.theses.fr/2014TELE0014/document.

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Vu que la modulation multi-porteuses est largement utilisée dans les communications sans fil et la radio cognitive (CR pour “Cognitive Radio”) améliore l’utilisation des ressources radio et du spectre, nous nous concentrons sur les réseaux radio cognitifs (CR) pour faire progresser l’allocation des ressources, le routage, et l’ajustement de la puissance d’émission vers les récepteurs (synthèse de faisceaux ou beamforming) dans cette thèse. Nous étudions deux types de modulations multi-porteuses :Orthogonal Frequency-Division Multiplexing (OFDM) à base d’ondelettes (WOFDM pourWavelet OFDM) et OFDM dans sa forme classique ou traditionnelle (OFDM s’appuyant sur la transformation de Fourier pour partager les ressources). WOFDM adopte Wavelet Packet Modulation (WPM) pour obtenir des lobes secondaires beaucoup plus faibles dans la densité spectrale de puissance du signal transmis en comparaison à OFDM. WPM permet de surcroit à WOFDM de s’affranchir du Préfixe Cyclique (indispensable à OFDM) et d’exploiter l’égalisation pour combattre l’Interférence entre Symboles (ISI). Nous évaluons la performance de WOFDM sous différentes conditions du canal radio. Nous comparons la performance de WOFDM, qui s’appuie sur l’égalisation dans le domaine temporel, à celle de OFDM, qui requiert l’utilisation du Préfixe Cyclique et opère dans le domaine fréquentiel
In view of the wide usage of multicarrier modulation in wireless communications and the prominent contribution of Cognitive Radio (CR) to deal with critical shortage of spectrum resource, we focus on multicarrier based cognitive radio networks to investigate general resource allocation issues: subcarrier allocation, power allocation, routing, and beamforming in this thesis. We investigate two types of multicarrier modulation: Wavelet-based Orthogonal Frequency Division Multiplexing (WOFDM) and Fourier-based Orthogonal Frequency Division Multiplexing (OFDM). WOFDM adopts Wavelet Packet Modulation (WPM). Compared with fourier-based OFDM, wavelet-based OFDM achieves much lower side lobe in the transmitted signal. Wavelet-based OFDM excludes Cyclic Prefix (CP) which is used in fourier-based OFDM systems. Wavelet-based OFDM turns to exploit equalization to combat Inter-Symbol Interference (ISI). We evaluate the performance of WOFDM under different channel conditions. We compare the performance of wavelet-based OFDM using equalization in the time domain to that of fourier-based OFDM with CP and the equalization in the frequency domain

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Bolívar, Díaz Nicolás. "Medium access control messaging scheme for cognitive radio networks". Doctoral thesis, Universitat de Girona, 2012. http://hdl.handle.net/10803/84098.

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Cognitive Radio (CR) is one possible option for mitigating the inefficient wireless spectrum distribution that occurs as a result of fixed spectrum allocation. The use of Dynamic Spectrum Access capabilities will potentially enable secondary users to utilize available and unoccupied frequency slots (channels) whenever the licensed users for those channels are absent. In Cognitive Radio Networks (CRNs), whenever users access the spectrum in an opportunistic manner, control messaging is a crucial issue to ensure that secondary users, i.e. Cognitive Radio Users (CRUs), do not interfere with the licensed users, i.e. Primary Users. In CRNs, where not all CRUs share the same set of channels, i.e. CRUs with Heterogeneous Frequency Devices (HFD), a set of channels must be chosen with care to allow all CRUs in the network to be able to transmit and receive control information. The thesis considers how Control Messaging Schemes (CMSs) can be used within CRNs and proposes a novel CMS for a CRN supporting HFDs. The thesis starts by classifying the CMSs; generating a new taxonomy and identifying the main characteristics for an efficient CRN with HFD. Then, different mathematical approaches for choosing the set of channels used for control information are presented. Next, a CMS for a CRN with HFDs model based upon the aforementioned characteristics and calculating the minimum number of channels for transmitting control information is proposed. Finally the thesis concludes with a number of CMS being presented and evaluated in terms of their impact upon transmission efficiency.

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Botero, Oscar. "Heterogeneous RFID framework design, analysis and evaluation". Phd thesis, Institut National des Télécommunications, 2012. http://tel.archives-ouvertes.fr/tel-00714120.

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The Internet of Things paradigm establishes interaction and communication with a huge amount of actors. The concept is not a new-from-scratch one; actually, it combines a vast number of technologies and protocols and surely adaptations of pre-existing elements to offer new services and applications. One of the key technologies of the Internet of Things is the Radio Frequency Identification just abbreviated RFID. This technology proposes a set of solutions that allow tracking and tracing persons, animals and practically any item wirelessly. Considering the Internet of Things concept, multiple technologies need to be linked in order to provide interactions that lead to the implementation of services and applications. The challenge is that these technologies are not necessarily compatible and designed to work with other technologies. Within this context, the main objective of this thesis is to design a heterogeneous framework that will permit the interaction of diverse devices such as RFID, sensors and actuators in order to provide new applications and services. For this purpose in this work, our first contribution is the design and analysis of an integration architecture for heterogeneous devices. In the second contribution, we propose an evaluation model for RFID topologies and an optimization tool that assists in the RFID network planning process. Finally, in our last contribution, we implemented a simplified version of the framework by using embedded hardware and performance metrics are provided as well as the detailed configuration of the test platform

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Çelebi, Mehmet Bahadır. "On the Improvement of the Capacity of the Heterogeneous Networks with Link-Level and System-Level Approaches". Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5353.

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Evolution of wireless services enabled the development of the advanced applications and shifted the paradigms of research in this field from voice to data centric. Such services are spreading like wildfire between users and hence, increasing the demand for large bandwidth. However, the frequency spectrum that is suitable for wireless mobile communications is already assigned to particular services from 400 MHz to several GHz. Also, allocating a large chunk of band continuously from the same part of the spectrum may not be possible due to spectral crowd. Therefore, meeting the demand for high data rate requiring wireless services within the accessible spectrum range becomes a challenging problem. The spectrum allocation policies are discussed by regulatory authorities and academia, and the idea of spectrum sharing systems are addressed as a solution. For instance, heterogeneous networks (HetNets) increase the number of available resources and improve the spectrum accessing capabilities of the wireless communication systems. To achieve this, HetNet nodes are deployed within the coverage of the macrocell regions. Thus, spectral efficiency is boosted via spatial reuse of the same spectral resources. On the contrary, HetNets preclude to fully exploit the resources because of serious interference problems between macrocell and HetNet nodes. Thus, wireless networks of the future will observe interference from even a larger number of sources. Due to co-channel HetNet deployment and denser frequency reuse, interference cancellation is expected to have significant importance for future wireless communication systems. The occupied resources can also be reused as a solution by conducting advanced signal processing algorithms at the receiver to increase the spectral efficiency. While doing so, the proposed approaches are expected to be easily integrated with the existing complementary approaches to improve the capacity further. Besides, new deployment strategies that allow spectrum access for non-licensed users to achieve larger bandwidth become important to increase the spectral efficiency of the HetNets. Within the scope of the dissertation, new solutions are developed for the aforementioned problems of the next-generation wireless communication systems. First, an interference cancellation receiver that exploits the unique characteristics of current waveforms is developed in Chapter 2. Also the unknown model of interference is converted to a known model and new algorithms are proposed to recover the desired signal. Then, another perspective is brought into the subject by transforming the interference problem to an interference advantage in Chapter 3. The idea of co-existence of different types of signals are analyzed to bring another degree of freedom as a solution. The proposed approaches are integrated to the existing complementary approaches, such as interference coordination and power control, to improve the capacity further. Finally, a cooperation mechanism is suggested to facilitate the transmission of signal which has a large bandwidth by integrating the idle bands in Chapter 4. By this way, geo-spatially idle bands within the coverage area are utilized and spectral efficiency is increased.

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19

Mendil, Mouhcine. "Joint radio and power resource optimal management for wireless cellular networks interconnected through smart grids". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT087/document.

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Face à l'explosion du trafic mobile entraînée par le succès des smartphones, les opérateurs de réseaux mobiles (MNOs) densifient leurs réseaux à travers le déploiement massif des stations de base à faible portée (SBS), capable d’offrir des services très haut débit et de remplir les exigences de capacité et de couverture. Cette nouvelle infrastructure, appelée réseau cellulaire hétérogène (HetNet), utilise un mix de stations de base hiérarchisées, comprenant des macro-cellule à forte puissance et des SBS à faible puissance.La prolifération des HetNets soulève une nouvelle préoccupation concernant leur consommation d'énergie et empreinte carbone. Dans ce contexte, l'utilisation de technologies de production d'énergie dans les réseaux mobiles a suscité un intérêt particulier. Les sources d'énergie respectueuses de l'environnement couplées à un système de stockage d'énergie ont le potentiel de réduire les émissions carbone ainsi que le coût opérationnel énergétique des MNOs.L'intégration des énergies renouvelables (panneau solaire) et du stockage d'énergie (batterie) dans un SBS gagne en efficacité grâce aux leviers technologiques et économiques apportés par le smart grid (SG). Cependant, l'architecture résultante, que nous appelons Green Small-Cell Base station (GSBS), est complexe. Premièrement, la multitude de sources d'énergie, le phénomène de viellissement du système et le prix dynamique de l'électricité dans le SG sont des facteurs qui nécessitent planification et gestion pour un fonctionnement plus efficace du GSBS. Deuxièmement, il existe une étroite dépendance entre le dimensionnement et le contrôle en temps réel du système, qui nécessite une approche commune capable de résoudre conjointement ces deux problèmes. Enfin, la gestion holistique d’un HetNet nécessite un schéma de contrôle à grande échelle pour optimiser simultanément les ressources énergétiques locales et la collaboration radio entre les SBSs.Par conséquent, nous avons élaboré un cadre d'optimisation pour le pré-déploiement et le post-déploiement du GSBS, afin de permettre aux MNOs de réduire conjointement leurs dépenses d'électricité et le vieillissement de leurs équipements. L'optimisation pré-déploiement consiste en un dimensionnement du GSBS qui tient compte du vieillissement de la batterie et de la stratégie de gestion des ressources énergétiques. Le problème associé est formulé et le dimensionnement optimal est approché en s'appuyant des profils moyens (production, consommation et prix de l'électricité) à travers une méthode itérative basée sur le solveur non-linéaire “fmincon”. Le schéma de post-déploiement repose sur des capacités d'apprentissage permettant d'ajuster dynamiquement la gestion énergétique du GSBS à son environnement (conditions météorologiques, charge de trafic et coût de l'électricité). La solution s'appuie sur le fuzzy Q-learning qui consiste à combiner le système d'inférence floue avec l'algorithme Q-learning. Ensuite, nous formalisons un système d'équilibrage de charge capable d'étendre la gestion énergétique locale à une collaboration à l'échelle réseau. Nous proposons à ce titre un algorithme en deux étapes, combinant des contrôleurs hiérarchiques au niveau du GSBS et au niveau du réseau. Les deux étapes s'alternent pour continuellement planifier et adapter la gestion de l'énergie à la collaboration radio dans le HetNet.Les résultats de la simulation montrent que, en considérant le vieillissement de la batterie et l'impact mutuel de la conception du système sur la stratégie énergétique (et vice-versa), le dimensionnement optimal du GSBS est capable de maximiser le retour sur investissement. En outre, grâce à ses capacités d'apprentissage, le GSBS peut être déployé de manière plug-and-play, avec la possibilité de s'auto-organiser, d'améliorer le coût énergétique du système et de préserver la durée de vie de la batterie
Pushed by an unprecedented increase in data traffic, Mobile Network Operators (MNOs) are densifying their networks through the deployment of Small-cell Base Stations (SBS), low-range radio-access transceivers that offer enhanced capacity and improved coverage. This new infrastructure – Heterogeneous cellular Network (HetNet) -- uses a hierarchy of high-power Macro-cell Base Stations overlaid with several low-power (SBSs).The augmenting deployment and operation of the HetNets raise a new crucial concern regarding their energy consumption and carbon footprint. In this context, the use of energy-harvesting technologies in mobile networks have gained particular interest. The environment-friendly power sources coupled with energy storage capabilities have the potential to reduce the carbon emissions as well as the electricity operating expenditures of MNOs.The integration of renewable energy (solar panel) and energy storage capability (battery) in SBSs gain in efficiency thanks to the technological and economic enablers brought by the Smart Grid (SG). However, the obtained architecture, which we call Green Small-Cell Base Station (GSBS), is complex. First, the multitude of power sources, the system aging, and the dynamic electricity price in the (SG) are factors that require design and management to enable the (GSBS) to efficiently operate. Second, there is a close dependence between the system sizing and control, which requires an approach to address these problems simultaneously. Finally, the achievement of a holistic management in a (HetNet) requires a network-level energy-aware scheme that jointly optimizes the local energy resources and radio collaboration between the SBSs.Accordingly, we have elaborated pre-deployment and post-deployment optimization frameworks for GSBSs that allow the MNOs to jointly reduce their electricity expenses and the equipment degradation. The pre-deployment optimization consists in an effective sizing of the GSBS that accounts for the battery aging and the associated management of the energy resources. The problem is formulated and the optimal sizing is approximated using average profiles, through an iterative method based on the non-linear solver “fmincon”. The post-deployment scheme relies on learning capabilities to dynamically adjust the GSBS energy management to its environment (weather conditions, traffic load, and electricity cost). The solution is based on the fuzzy Q-learning that consists in tuning a fuzzy inference system (which represents the energy arbitrage in the system) with the Q-learning algorithm. Then, we formalize an energy-aware load-balancing scheme to extend the local energy management to a network-level collaboration. We propose a two-stage algorithm to solve the formulated problem by combining hierarchical controllers at the GSBS-level and at the network-level. The two stages are alternated to continuously plan and adapt the energy management to the radio collaboration in the HetNet.Simulation results show that, by considering the battery aging and the impact of the system design and the energy strategy on each other, the optimal sizing of the GSBS is able to maximize the return on investment with respect to the technical and economic conditions of the deployment. Also, thanks to its learning capabilities, the GSBSs can be deployed in a plug-and-play fashion, with the ability to self-organize, improve the operating energy cost of the system, and preserves the battery lifespan

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20

Aburas, Akram. "Operating System Based Perceptual Evaluation of Call Quality in Radio Telecommunications Networks. Development of call quality assessment at mobile terminals using the Symbian operating system, comparison with traditional approaches and proposals for a tariff regime relating call charging to perceived speech quality". Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5479.

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Call quality has been crucial from the inception of telecommunication networks. Operators need to monitor call quality from the end-user's perspective, in order to retain subscribers and reduce subscriber 'churn'. Operators worry not only about call quality and interconnect revenue loss, but also about network connectivity issues in areas where mobile network gateways are prevalent. Bandwidth quality as experienced by the end-user is equally important in helping operators to reduce churn. The parameters that network operators use to improve call quality are mainly from the end-user's perspective. These parameters are usually ASR (answer seizure ratio), PDD (postdial delay), NER (network efficiency ratio), the number of calls for which these parameters have been analyzed and successful calls. Operators use these parameters to evaluate and optimize the network to meet their quality requirements. Analysis of speech quality is a major arena for research. Traditionally, users' perception of speech quality has been measured offline using subjective listening tests. Such tests are, however, slow, tedious and costly. An alternative method is therefore needed; one that can be automatically computed on the subscriber's handset, be available to the operator as well as to subscribers and, at the same time, provide results that are comparable with conventional subjective scores. QMeter® 'a set of tools for signal and bandwidth measurement that have been developed bearing in mind all the parameters that influence call and bandwidth quality experienced by the end-user' addresses these issues and, additionally, facilitates dynamic tariff propositions which enhance the credibility of the operator. This research focuses on call quality parameters from the end-user's perspective. The call parameters used in the research are signal strength, successful call rate, normal drop call rate, and hand-over drop rate. Signal strength is measured for every five milliseconds of an active call and average signal strength is calculated for each successful call. The successful call rate, normal drop rate and hand-over drop rate are used to achieve a measurement of the overall call quality. Call quality with respect to bundles of 10 calls is proposed. An attempt is made to visualize these parameters for better understanding of where the quality is bad, good and excellent. This will help operators, as well as user groups, to measure quality and coverage. Operators boast about their bandwidth but in reality, to know the locations where speed has to be improved, they need a tool that can effectively measure speed from the end-user's perspective. BM (bandwidth meter), a tool developed as a part of this research, measures the average speed of data sessions and stores the information for analysis at different locations. To address issues of quality in the subscriber segment, this research proposes the varying of tariffs based on call and bandwidth quality. Call charging based on call quality as perceived by the end-user is proposed, both to satisfy subscribers and help operators to improve customer satisfaction and increase average revenue per user. Tariff redemption procedures are put forward for bundles of 10 calls and 10 data sessions. In addition to the varying of tariffs, quality escalation processes are proposed. Deploying such tools on selected or random samples of users will result in substantial improvement in user loyalty which, in turn, will bring operational and economic advantages.

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21

Abozariba, Raouf. "Generalised radio resource sharing framework for heterogeneous radio networks". Thesis, Staffordshire University, 2017. http://eprints.staffs.ac.uk/4197/.

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Recent years have seen a significant interest in quantitative measurements of licensed and unlicensed spectrum use. Several research groups, companies and regulatory bodies have conducted studies of varying times and locations with the aim to capture the over- all utilisation rate of spectrum. The studies have shown that large amount of allocated spectrum are under-utilised, and create the so called "spectrum holes", resulting in a waste of valuable frequency resources. In order to satisfy the requirements of increased demands of spectrum resources and to improve spectrum utilisation, dynamic spectrum sharing (DSS) is proposed in the literature along with cognitive radio networks (CRNs). DSS and CRNs have been studied from many perspectives, for example spectrum sensing to identify the idle channels has been under the microscope to improve detection proba- bility. As well as spectrum sensing, the DSS performance analysis remains an important topic moving towards better spectrum utilisation to meet the exponential growth of traffic demand. In this dissertation we have studied both techniques to achieve different objectives such as enhancing the probability of detection and spectrum utilisation. In order to improve spectrum sensing decisions we have proposed a cooperative spec- trum sensing scheme which takes the propagation conditions into consideration. The proposed location aware scheme shows an improved performance over conventional hard combination scheme, highlighting the requirements of location awareness in cognitive radio networks (CRNs). Due to the exponentially growing wireless applications and services, traffic demand is increasing rapidly. To cope with such growth wireless network operators seek radio resource cooperation strategies for their users with the highest possible grade of service (GoS). However, it is difficult to fathom the potential benefits of such cooperation, thus we propose a set of analytical models for DSS to analyse the blocking probability gain and degradation for operators. The thesis focuses on examining the performance gains that DSS can entail, in different scenarios. A number of dynamic spectrum sharing scenarios are proposed. The proposed models focus on measuring the blocking probability of secondary network operators as a trade-off with a marginal increase of the blocking probability of a primary network in return of monetary rewards. We derived the global balance equation and an explicit expression of the blocking probability for each model. The robustness of the proposed analytical models is evaluated under different scenarios by considering varying tra�c intensities, different network sizes and adding reserved resources (or pooled capacity). The results show that the blocking probabilities can be reduced significantly with the proposed analytical DSS models in comparison to the existing local spectrum access schemes. In addition to the sharing models, we further assume that the secondary operator aims to borrow spectrum bandwidths from primary operators when more spectrum resources available for borrowing than the actual demand considering a merchant mode. Two optimisation models are proposed using stochastic optimisation models in which the secondary operator (i) spends the minimum amount of money to achieve the target GoS assuming an unrestricted budget or (ii) gains the maximum amount of profit to achieve the target GoS assuming restricted budget. Results obtained from each model are then compared with results derived from algorithms in which spectrum borrowings were random. Comparisons showed that the gain in the results obtained from our proposed stochastic optimisation model is significantly higher than heuristic counterparts. A post-optimisation performance analysis of the operators in the form of analysis of blocking probability in various scenarios is investigated to determine the probable per- formance gain and degradation of the secondary and primary operators respectively. We mathematically model the sharing agreement scenario and derive the closed form solution of blocking probabilities for each operator. Results show how the secondary and primary operators perform in terms of blocking probability under various offered loads and sharing capacity. The simulation results demonstrate that at most trading windows, the proposed opti- mal algorithms outperforms their heuristic counterparts. When we consider 80 cells, the proposed profit maximisation algorithm results in 33.3% gain in net pro�t to the secondary operators as well as facilitating 2.35% more resources than the heuristic ap- proach. In addition, the cost minimisation algorithm results in 46.34% gain over the heuristic algorithm when considering the same number of cells (80).

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Ngo, Duy. "Radio resource allocation for wireless heterogeneous networks". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119622.

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By deploying small cells (i.e., femtocells) within the same service area of regular macrocells, a much higher area spectral efficiency, better indoor coverage, and significant mobile data offloading can be achieved at low cost. Because femtocells reuse the radio spectrum already assigned to macrocells in an uncoordinated fashion, new cell boundaries are created and the signal interference situation becomes far more unpredictable than in conventional networks. In this heterogeneous network setting, adaptive power allocation and dynamic spectrum access are needed to ensure a harmonized coexistence of network entities with diverse design specifications. Since femtocells are deployed by end users without any network planning, autonomous solutions are desirable to effectively control the severe intra-tier and cross-tier interferences. In this study, we develop and evaluate distributed radio resource allocation algorithms for wireless heterogeneous networks employing code-division multiple access (CDMA) and orthogonal frequency division multiple access (OFDMA). Requiring no central coordination, the devised solutions robustly protect the ongoing operation of all existing macrocell users, while optimally exploiting the residual network capacity for femtocells. In CDMA-based networks, we propose a dynamic pricing scheme combined with femtocell user admission control to indirectly manage the cross-tier interference. The proposed joint power and admission control algorithms can be locally executed at each link to offer a maximum utility to individual users. For the total network utility maximization, we develop joint Pareto-optimal power control and signal-to-interference-plus-noise ratio (SINR) assignment algorithms that can fairly share radio resources among users. Upon applying convex optimization methods, the minimum SINRs prescribed by macrocell users are effectively enforced, whereas the sum network utility is globally maximized. In OFDMA-based networks, to resolve the highly nonconvex and combinatorial problem of joint power and subchannel allocation, we propose a dynamic spectrum management scheme that alternatively optimizes the powers and assigns the subchannels. With the adopted successive convex approximation approach, the total throughput of all femtocells is maximized whilst the macrocell network capacity is always protected. In cognitive femtocells where femtocell users opportunistically access the spectrum licensed to macrocells, we apply Lagrangian duality to devise jointly optimal power and subchannel allocation algorithms. The distributed solutions are shown to achieve their global optimality with low complexity.
En déployant de petites cellules (dénommées les femtocells) au sein de la même zone de service que les cellules de tailles régulières (dénommées cellules macro), une efficacité spectrale zone beaucoup plus élevé, une meilleure couverture à l'intérieur, et d'importantes données mobiles de déchargement entre les deux cellules peuvent être réalisé tout en gardant faible coût. Vu que les femtocells réutilisent le spectre de fréquence déjà consacré à la cellule macro, auxquelles ils sont assignés, d'une manière non-coordonnée, de nouvelles limites de cellules sont créées et l'interférence devient beaucoup plus imprévisible que dans les réseaux traditionnels. Dans ce contexte réseau hétérogène, une allocation adaptative de puissance et des méthodes d'accès dynamiques au spectre sont nécessaires pour assurer une coexistence harmonisée des entités du réseau avec les nouvelles spécifications imposées par les femtocells. Depuis que les femtocells sont déployées par les terminaux sans aucune planification au préalable du réseau, des solutions qui s'adaptent automatiquement sont toujours désirable pour contrôler efficacement les sévères interférences entre les différents niveaux du réseau sans fil hétérogène.Dans cette étude, nous développons et évaluons des algorithmes distribués pour l'allocation de ressources radio dans les réseaux sans fil hétérogènes employant l accès multiple par répartition en code (CDMA) et Accès multiple par répartition en fréquence (OFDMA). En évitant une coordination centralisée, les solutions proposées protègent le fonctionnement de tous les utilisateurs de la cellule macro existantes, tout en exploitant de manière optimale la capacité résiduelle du réseau pour les utilisateurs du femtocells. Dans les réseaux CDMA, nous proposons un schéma de tarification dynamique associé à un contrôle d'admission des utilisateurs de la femtocell nous permettant de gérer indirectement l'interférence inter-niveaux (entre cellule macro et femtocell). Le contrôle simultané de la puissance et les algorithmes de contrôle d'admission proposés peut être exécuté localement sur chaque lien pour offrir un maximum d'utilité pour les utilisateurs individuels. Pour maximiser l'utilité totale du réseau, nous développons un algorithme de contrôle simultané de puissance basant sur l'optimalité de Pareto et le rapport signal sur interférence plus bruit (SINR) qui peut partager équitablement les ressources radio entre les utilisateurs. En appliquant d'une méthode d'optimisation, les SINR minimaux prescrits par les utilisateurs des cellules macro sont garantis, alors que le maximal global la somme de l'utilité du réseau est trouvé.Dans les réseaux OFDMA, afin de résoudre le problème non convexe et combinatoire de l'allocation conjointe de la puissance et des sous-porteuses, nous proposons un schéma alternatif de gestion dynamique du spectre qui optimise la distribution de puissance et des sous-porteuses. Avec l'approche par approximations successives convexe adoptée, le débit total de tous les femtocells est maximisé alors que la capacité du réseau de la cellule macro est toujours protégée. En femtocells cognitives où les utilisateurs du femtocell accèdent au spectre autorisé à la cellule macro d'une manière opportuniste, nous appliquons la dualité lagrangienne pour optimiser la distribution de la puissance et des sous-porteuses. Nous prouvons que les solutions distribuées proposées atteignent leur optimal global avec une faible complexité.

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Baydogan, Mustafa Gokce. "Energy Efficient Coverage And Connectivity Problem In Wireless Sensor Networks". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609688/index.pdf.

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In this thesis, we study the energy efficient coverage and connectivity problem in wireless sensor networks (WSNs). We try to locate heterogeneous sensors and route data generated to a base station under two conflicting objectives: minimization of network cost and maximization of network lifetime. We aim at satisfying connectivity and coverage requirements as well as sensor node and link capacity constraints. We propose mathematical formulations and use an exact solution approach to find Pareto optimal solutions for the problem. We also develop a multiobjective genetic algorithm to approximate the efficient frontier, as the exact solution approach requires long computation times. We experiment with our genetic algorithm on randomly generated problems to test how well the heuristic procedure approximates the efficient frontier. Our results show that our genetic algorithm approximates the efficient frontier well in reasonable computation times.

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Bastos, Joaquim Manuel Camões Sobral de. "Energy Efficient Radio Resource Management for Heterogeneous Networks". Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668364.

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In the continuous evolution of mobile communication systems, there are many issues and aspects to be addressed, as well as in their effective implementation and deployment on cellular networks. In a general way, the most outstanding challenge is how to take the most advantage from the available resources, namely RF spectrum, to satisfy the communication requirements associated to a specific service or application offered to an end user. Energy efficiency has also become one important aspect associated to such requirements, since it has a significant practical impact on operators, namely regarding their networks operational expenditure, as well as on UEs, concerning their battery duration and associated autonomy. This thesis addresses and targets contributing to the growing concerns regarding energy efficiency in the ICT industry, specifically focusing on cellular wireless networks. Moreover, taking into account the current panorama and developments in this field, namely concerning the emerging 5G communication systems and networks, the heterogeneous network (HetNet) concept is also at the core of the work that has been carried out and is presented in this thesis. The work takes into consideration the two ends of the considered system of networks. The first are the nomad end users that should be able to roam freely in such system, always with continuous service provided in a seamless way, and the second is the core network managed by the respective telecommunications operator. To achieve this, the work carried out focused in addressing two key challenges in HetNets in general, specifically towards optimizing the energy efficiency associated to vertical handovers (VHO) and to radio resource management (RRM) mechanisms and approaches to allow energy efficient communication in a HetNet. The work addresses energy efficiency in two different perspectives, each using a different solution exploiting distinct available mechanisms specified for cellular wireless networks. One considers UEs integrating multiple RAT interfaces, and involve a VHO-based solution exploiting IEEE 802.21 standard, and the other targets both core and radio access networks, exploiting a RRM-based solution. The first proposed energy efficient solution exploiting features provided by IEEE 802.21 (MIH/MIIS) and VHO, targeting energy saving at modern multi-RAT mobile UEs, can eventually reduce the energy consumption at their RAT interfaces by roughly 30% on average, with a straightforward implementation, according to the attained simulation results. However, the currently proposed scheme presents a trade-off in terms of added packet loss linked to UEs velocity, which is mostly caused by delayed network re-association. In the second solution, for downlink OFDMA HetNet system, the proposed energy efficiency optimization algorithm for radio resource allocation, taking a given data rate requirement into account, associated to QoS, presented fast convergence, which is key in the design of real EE HetNet systems. The algorithm considers not only the radiated power, but also both types of the circuit power. Simulation results can eventually be exploited towards designing optimal energy consumption networks based on QoS-oriented HetNet method, while total power is fixed. As future work it would also be important to take into account the paradigm shift that arise with the emergence of new standards, namely 3GPP Release 15, placing the stepping stones for 5G systems and networks. In this perspective, at a first instance, it is key to go beyond the assumptions made in this work, by considering C-RAN architecture in the addressed challenge for achieving higher EE, which is a prime concern when redesigning existing and future mobile communication systems, namely in sustainable and environmental perspectives.
La continua y rápida evolución de los sistemas de comunicación actuales presenta diversas líneas de actuación, con aspectos muy diversos como el despliegue e implementación eficiente de redes celulares. En este ámbito, el mayor desafío se presenta en cómo aprovechar los recursos disponibles, principalmente en cuanto al espectro RF, para satisfacer los requisitos asociados a los servicios o aplicaciones específicas ofrecidas al usuario final. La eficiencia energética también se ha convertido en un aspecto importante, dentro de los mencionados requisitos, debido al impacto que tiene para los operadores con respecto al coste operacional de las redes, y para el usuario final, debido al efecto en la autonomía de los dispositivos móviles. Este trabajo aborda la eficiencia energética en dos perspectivas diferentes, cada una utilizando una solución diferente que explota los distintos mecanismos disponibles especificados de las redes inalámbricas celulares, en particular HetNets. Uno considera que los dispositivos móviles integran múltiples interfaces RAT e involucran una solución basada en VHO que explota el estándar IEEE 802.21, y el otro apunta a las redes de acceso radio y núcleo de red, explotando una solución basada en RRM. La primera solución de eficiencia energética propuesta aprovecha las características proporcionadas por IEEE 802.21 (MIH / MIIS) y VHO para obtener un ahorro de energía en los dispositivos móviles modernos multi-RAT, y puede eventualmente reducir el consumo de energía en sus interfaces RAT en aproximadamente un 30% en promedio, con una sencilla implementación, de acuerdo con los resultados de la simulación. En la segunda solución, para el sistema OFDMA HetNet de enlace descendente, el algoritmo de optimización de eficiencia energética propuesto para la asignación de recursos de radio, teniendo en cuenta un dado requisito de velocidad de datos, asociado a QoS, presentó una convergencia rápida, lo cual es clave en el diseño de sistemas EE HetNet. El algoritmo considera no solo la potencia radiada, sino también los dos tipos de potencia del circuito. Los resultados de la simulación pueden aprovecharse para diseñar redes de consumo de energía óptimas basadas en el método HetNet orientado a QoS con una potencia total fija.

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25

Schmidt, Robert. "Slicing in heterogeneous software-defined radio access networks". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS525.

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Les réseaux 5G sont envisagés comme un changement de paradigme vers des réseaux orientés services. Dans cette thèse, nous étudions comment combiner efficacement le découpage en tranches et le SD-RAN afin de fournir le niveau requis de flexibilité et de programmabilité dans l'infrastructure RAN pour réaliser des réseaux multi-locataires orientés services. Premièrement, nous concevons une abstraction d'une station de base pour représenter les stations de base logiques et décrire un service de réseau virtualisé. Deuxièmement, nous proposons une nouvelle plateforme SD-RAN conforme aux normes, appelée FlexRIC, sous la forme d'un kit de développement logiciel (SDK). Troisièmement, nous fournissons une conception modulaire pour un cadre d'ordonnancement MAC tenant compte des tranches afin de gérer et de contrôler efficacement les ressources radio dans un environnement multiservice avec un support de qualité de service (QoS). Enfin, nous présentons une couche de virtualisation SD-RAN dynamique basée sur le SDK FlexRIC et le cadre d'ordonnancement MAC pour composer de manière flexible une infrastructure SD-RAN multiservice et fournir une programmabilité pour de multiples contrôleurs SD-RAN
5G networks are envisioned to be a paradigm shift towards service-oriented networks. In this thesis, we investigate how to efficiently combine slicing and SD-RAN to provide the required level of flexibility and programmability in the RAN infrastructure to realize service-oriented multi-tenant networks. First, we devise an abstraction of a base station to represent logical base stations and describe a virtualized network service. Second, we propose a novel standard-compliant SD-RAN platform, named FlexRIC, in the form of a software development kit (SDK). Third, we provide a modular design for a slice-aware MAC scheduling framework to efficiently manage and control the radio resources in a multi-service environment with quality-of-service (QoS) support. Finally, we present a dynamic SD-RAN virtualization layer based on the FlexRIC SDK and MAC scheduling framework to flexibly compose a multi-service SD-RAN infrastructure and provide programmability for multiple SD-RAN controllers

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Silva, Carlos Filipe Moreira e. "Common radio resource management in wireless heterogeneous networks". Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/3992.

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Mestrado em Electrónica e Telecomunicações
A tecnologia de sinais de rádio frequência sobre fibra óptica involve o uso de links ópticos para transportar os sinais desde a unidade central de processamento até aos sites remotos (e vice-versa). A centralização do processamento dos sinais de rádio frequência permite a partilha de equipamentos, alocação dinâmica de recursos e uma manutenção mais simplificada do sistema. Embora o conceito de gestão comum dos recursos rádio tenha despertado grande interesse na comunidade científica em termos da melhor utilização desses recursos e de novos modelos de negócio, a verdade é que a sua implementação não tem sido fácil. A interligação entre diferentes componentes de rede, normalmente localizados em locais diferentes, introduz um grande atraso nas comunicações; por outro lado as implementações proprietárias e a escassez de informação global não satisfazem os requisitos de um ambiente extremamente dinâmico, como é o ambiente wireless. Uma topologia centralizada permite ultrapassar estas contrariedades, disponibilizando uma interligação eficiente entre as entidades locais e comuns de gestão de recursos rádio. Nesta dissertação é apresentada uma nova arquitectura de gestão comum de recursos rádio, baseada no conceito de interligação entre diferentes tecnologias de acesso. Esta arquitectura faz a gestão dos recursos rádio de forma centralizada, onde os sinais rádio chegam sem qualquer pré-processamento. Essa arquitectura é avaliada com a implementação de um algoritmo simples de balanceamento da carga que segue a politica de minimização da interferência e aumento da capacidade. As simulações com duas tecnologias de acesso, quando consideradas separas ou em agregado, mostraram um aumento do débito de pelo menos 51% para o mesmo valor de interferência enquanto que o erro de simbolo decresce pelo menos 20%.
Radio over fibre technology involves the use of optical fibre links to distribute radio frequency signals from a central location to remote sites (and viceversa). The centralisation of radio frequency signals processing functions enables equipment sharing, dynamic allocation of resources, and simplified system operation and maintenance. Despite the unquestionable interest concept of common radio resource management from the point of view of resource usage and novel business models, its implementation has not been easy. The interworking between the different local radio resource management entities, usually located on different places will not satisfy the requirements of the wireless dynamic behaviour due to increase of delay in communication process, less information availability and proprietary implementations. A centralised topology can overcome the drawbacks of former wireless systems architecture interconnection by providing an efficient common radio communication flow with the local radio resource management entities. In this thesis a novel common radio resource management architecture is presented based on the concept of inter-working between different technologies. This is a centralised architecture where the radio frequency signals are delivered to the central location through the optical links. The new architecture is evaluated with a common policy that minimises interference while the overall system capacity is increased. The policy is implemented through the load balancing algorithm. The simulations of two radio access technologies when separately and jointly considered show that when the load balancing algorithm is applied the available throughput increases in at least 51% while the symbol error rate decreases at least 20%.

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El, Helou Melhem. "Radio Access Technology Selection in Heterogeneous Wireless Networks". Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S086/document.

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Pour faire face à la croissance rapide du trafic mobile, différentes technologies d'accès radio (par exemple, HSPA, LTE, WiFi, et WiMAX) sont intégrées et gérées conjointement. Dans ce contexte, la sélection de TAR est une fonction clé pour améliorer les performances du réseau et l'expérience de l'utilisateur. Elle consiste à décider quelle TAR est la plus appropriée aux mobiles. Quand l'intelligence est poussée à la périphérie du réseau, les mobiles décident de manière autonome de leur meilleur TAR. Ils cherchent à maximiser égoïstement leur utilité. Toutefois, puisque les mobiles ne disposent d'aucune information sur les conditions de charge du réseau, leurs décisions peuvent conduire à une inefficacité de la performance. En outre, déléguer les décisions au réseau optimise la performance globale, mais au prix d'une augmentation de la complexité du réseau, des charges de signalisation et de traitement. Dans cette thèse, au lieu de favoriser une de ces deux approches décisionnelles, nous proposons un cadre de décision hybride: le réseau fournit des informations pour les mobiles pour mieux décider de leur TAR. Plus précisément, les utilisateurs mobiles choisissent leur TAR en fonction de leurs besoins et préférences individuelles, ainsi que des paramètres de coût monétaire et de QoS signalés par le réseau. En ajustant convenablement les informations du réseau, les décisions des utilisateurs répondent globalement aux objectifs de l'opérateur. Nous introduisons d'abord notre cadre de décision hybride. Afin de maximiser l'expérience de l'utilisateur, nous présentons une méthode de décision multicritère (MDMC) basée sur la satisfaction. Outre leurs conditions radio, les utilisateurs mobiles tiennent compte des paramètres de coût et de QoS, signalées par le réseau, pour évaluer les TAR disponibles. En comparaison avec les solutions existantes, notre algorithme répond aux besoins de l'utilisateur (par exemple, les demandes en débit, la tolérance de coût, la classe de trafic), et évite les décisions inadéquates. Une attention particulière est ensuite portée au réseau pour s'assurer qu'il diffuse des informations décisionnelles appropriées, afin de mieux exploiter ses ressources radio alors que les mobiles maximisent leur propre utilité. Nous présentons deux méthodes heuristiques pour dériver dynamiquement quoi signaler aux mobiles. Puisque les paramètres de QoS sont modulées en fonction des conditions de charge, l'exploitation des ressources radio s'est avérée efficace. Aussi, nous nous concentrons sur l'optimisation de l'information du réseau. La dérivation des paramètres de QoS est formulée comme un processus de décision semi-markovien, et les stratégies optimales sont calculées en utilisant l'algorithme de Policy Iteration. En outre, et puisque les paramètres du réseau ne peuvent pas être facilement obtenues, une approche par apprentissage par renforcement est introduite pour dériver quoi signaler aux mobiles
To cope with the rapid growth of mobile broadband traffic, various radio access technologies (e.g., HSPA, LTE, WiFi, and WiMAX) are being integrated and jointly managed. Radio Access Technology (RAT) selection, devoted to decide to what RAT mobiles should connect, is a key functionality to improve network performance and user experience. When intelligence is pushed to the network edge, mobiles make autonomous decisions regarding selection of their most appropriate RAT. They aim to selfishly maximize their utility. However, because mobiles have no information on network load conditions, their decisions may lead to performance inefficiency. Moreover, delegating decisions to the network optimizes overall performance, but at the cost of increased network complexity, signaling, and processing load. In this thesis, instead of favoring either of these decision-making approaches, we propose a hybrid decision framework: the network provides information for the mobiles to make robust RAT selections. More precisely, mobile users select their RAT depending on their individual needs and preferences, as well as on the monetary cost and QoS parameters signaled by the network. By appropriately tuning network information, user decisions are globally expected to meet operator objectives, avoiding undesirable network states. We first introduce our hybrid decision framework. Decision makings, on the network and user sides, are investigated. To maximize user experience, we present a satisfaction-based Multi-Criteria Decision-Making (MCDM) method. In addition to their radio conditions, mobile users consider the cost and QoS parameters, signaled by the network, to evaluate serving RATs. In comparison with existing MCDM solutions, our algorithm meets user needs (e.g., traffic class, throughput demand, cost tolerance), avoiding inadequate decisions. A particular attention is then addressed to the network to make sure it broadcasts suitable decisional information, so as to better exploit its radio resources while mobiles maximize their own utility. We present two heuristic methods to dynamically derive what to signal to mobiles. While QoS parameters are modulated as a function of the load conditions, radio resources are shown to be efficiently exploited. Moreover, we focus on optimizing network information. Deriving QoS parameters is formulated as a semi-Markov decision process, and optimal policies are computed using the Policy Iteration algorithm. Also, and since network parameters may not be easily obtained, a reinforcement learning approach is introduced to derive what to signal to mobiles. The performances of optimal, learning-based, and heuristic policies are analyzed. When thresholds are pertinently set, our heuristic method provides performance very close to the optimal solution. Moreover, although lower performances are observed, our learning-based algorithm has the crucial advantage of requiring no prior parameterization

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Jouini, Hana. "Radio Resource Management in LTE Networks : Load Balancing in Heterogeneous Cellular Networks". Thesis, Paris, CNAM, 2017. http://www.theses.fr/2017CNAM1153/document.

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Face à la croissance exponentielle des réseaux mobiles très haut débit, les opérateurs de téléphonie mobile se sont lancé dans le déploiement des réseaux dits hiérarchiques (HetNet), composés par des sous-réseaux avec des caractéristiques divergentes en termes de type des cellules déployées et des technologies d’accès radio utilisées. Avec ce caractère hétérogène des réseaux cellulaire, l’exploitation de ces derniers devienne de plus en plus compliquée et coûteuse impliquant le déploiement, la configuration et la reconfiguration de stations de base et d’équipements de différentes caractéristiques. Ainsi, l’intégration dans les réseaux HetNet de fonctionnalités d’auto-configuration automatisant et simplifiant l’exploitation des réseaux deviennent une demande forte des opérateurs. Cette thèse a pour objectif l’étude et le développement de solutions de gestion dynamique de l’équilibrage de charges entre les différentes couches composant un même HetNet, pour une expérience utilisateur (QoE) améliorée. Dans ce contexte, une classe des algorithmes d’équilibrage de charges dite ‘équilibrage de charges par adaptation dynamique des paramètres de la procédure de handover’ est étudiée. Pour commencer, nous développons un modèle théorique basé sur des solutions et des outils de la géométrie stochastique et incorporant le caractère hétérogène des réseaux cellulaires. Ensuite nous exploitons ce modèle pour introduire des algorithmes d’adaptation des paramètres de handover basés sur la maximisation de la puissance reçue et du rapport signal/brouillage plus bruit (SINR). Nous exploitons ces résultats pour implémenter et étudier, par simulation à évènements discrets, des algorithmes d’équilibrage de charges dans le contexte des réseaux LTE HetNet auto-organisés basés sur les spécifications 3GPP. Ces travaux soulignent l’importance de l’équilibrage de charges afin de booster les performances des réseaux cellulaires en termes de débit global transmis, perte de paquets de données et utilisation optimisée des ressources radio
High demands on mobile networks provide a fresh opportunity to migrate towardsmulti-tier deployments, denoted as heterogeneous network (HetNet), involving a mix of cell types and radio access technologies working together seamlessly. In this context, network optimisation functionalities such as load balancing have to be properly engineered so that HetNet benefit are fully exploited. This dissertation aims to develop tractable frameworks to model and analyze load balancing dynamics while incorporating the heterogeneous nature of cellular networks. In this context we investigate and analyze a class of load balancingstrategies, namely adaptive handover based load balancing strategies. These latter were firstly studied under the general heading of stochastic networks using independent and homogeneous Poisson point processes based network model. We propose a baseline model to characterize rate coverage and handover signalling in K-tier HetNet with a general maximum power based cell association and adaptive handover strategies. Tiers differ in terms of deployment density and cells characteristics (i.e. transmit power, bandwidth, and path loss exponent). One of the main outcomes is demonstrating the impact of offloading traffic from macro- to small-tier. This impact was studied in terms of rate coverage and HO signalling. Results show that enhancement in rate coverage is penalized by HO signalling overhead. Then appropriate algorithms of LB based adaptive HO are designed and their performance is evaluated by means of extensive system level simulations. These latter are conducted in 3GPP defined scenarios, including representation of mobility procedures in both connectedstate. Simulation results show that the proposed LB algorithms ensure performance enhancement in terms of network throughput, packet loss ratio, fairness and HO signalling

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Adedoyin, Mary Abosede. "Efficient radio resource management for future generation heterogeneous wireless networks". Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/27873.

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The heterogeneous deployment of small cells (e.g., femtocells) in the coverage area of the traditional macrocells is a cost-efficient solution to provide network capacity, indoor coverage and green communications towards sustainable environments in the future fifth generation (5G) wireless networks. However, the unplanned and ultra-dense deployment of femtocells with their uncoordinated operations will result in technical challenges such as severe interference, a significant increase in total energy consumption, unfairness in radio resource sharing and inadequate quality of service provisioning. Therefore, there is a need to develop efficient radio resource management algorithms that will address the above-mentioned technical challenges. The aim of this thesis is to develop and evaluate new efficient radio resource management algorithms that will be implemented in cognitive radio enabled femtocells to guarantee the economical sustainability of broadband wireless communications and users' quality of service in terms of throughput and fairness. Cognitive Radio (CR) technology with the Dynamic Spectrum Access (DSA) and stochastic process are the key technologies utilized in this research to increase the spectrum efficiency and energy efficiency at limited interference. This thesis essentially investigates three research issues relating to the efficient radio resource management: Firstly, a self-organizing radio resource management algorithm for radio resource allocation and interference management is proposed. The algorithm considers the effect of imperfect spectrum sensing in detecting the available transmission opportunities to maximize the throughput of femtocell users while keeping interference below pre-determined thresholds and ensuring fairness in radio resource sharing among users. Secondly, the effect of maximizing the energy efficiency and the spectrum efficiency individually on radio resource management is investigated. Then, an energy-efficient radio resource management algorithm and a spectrum-efficient radio resource management algorithm are proposed for green communication, to improve the probabilities of spectrum access and further increase the network capacity for sustainable environments. Also, a joint maximization of the energy efficiency and spectrum efficiency of the overall networks is considered since joint optimization of energy efficiency and spectrum efficiency is one of the goals of 5G wireless networks. Unfortunately, maximizing the energy efficiency results in low performance of the spectrum efficiency and vice versa. Therefore, there is an investigation on how to balance the trade-off that arises when maximizing both the energy efficiency and the spectrum efficiency simultaneously. Hence, a joint energy efficiency and spectrum efficiency trade-off algorithm is proposed for radio resource allocation in ultra-dense heterogeneous networks based on orthogonal frequency division multiple access. Lastly, a joint radio resource allocation with adaptive modulation and coding scheme is proposed to minimize the total transmit power across femtocells by considering the location and the service requirements of each user in the network. The performance of the proposed algorithms is evaluated by simulation and numerical analysis to demonstrate the impact of ultra-dense deployment of femtocells on the macrocell networks. The results show that the proposed algorithms offer improved performance in terms of throughput, fairness, power control, spectrum efficiency and energy efficiency. Also, the proposed algorithms display excellent performance in dynamic wireless environments.

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Koudouridis, Georgios. "Study of Multi-Radio Transmission Diversity in Heterogeneous Access Networks". Licentiate thesis, KTH, Kommunikationsnät, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122723.

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With the advent of multi-radio access (MRA), an integration of differentradio access technologies (RATs) into a heterogeneous radio access network(RAN) becomes feasible. Such integration allows a user to be at any instantof time served by one or multiple radio accesses (RAs) concurrently, where anRA constitutes an independent radio resource, such as a carrier or a channel,implemented by a single RAT. It also allows a user´s service demands to bemapped onto the aggregated network resources in a transparent and efficientway. An approach for the realization of such multi-radio integrated environmentsis through a unifying generic link layer (GLL) that provides joint radiolink processing and enables communication between nodes and devices acrossdifferent radio accesses.Based on the requirements on multi-access, an architecture that supportsMRA is suggested and the functions of GLL that aims at integrating andutilising multiple RATs are defined. We explore the potential for performanceimprovements through novel extensions of the transmission diversityparadigm which builds on GLL functions that enable multi-radio access selection.Multi-radio transmission diversity (MRTD) is defined as the dynamicselection of radio access for the transmission of a user´s data and it can bethought of as consisting of a packet scheduler operating across multiple radiointerfaces. Different MRTD schemes may be envisaged through combinationsof access re-selection rate, transmission parallelism and transmission redundancy.The re-selection rate refers to the rate at which radio access selectionis performed. It may range from multiple IP packets to one single MACframe. Switched MRTD corresponds to an access selection scheme where auser transmits via one RA at a time, while parallel MRTD corresponds to ascheme where simultaneous transmissions over multiple RAs are scheduled.Finally, redundancy refers to the transmission of copies of the same data overmultiple RAs to increase the possibility of correct reception.The benefits of MRTD are investigated by simulation studies on two multiradiocase scenarios, based on generic RATs and on specific RATs respectively.In the RAT generic scenario, switched MRTD has been evaluated for networktopologies of collocated and non-collocated RAs consisting of macroand pico-cells. In the case of collocated RAs, spectral efficiency is increasedby exploiting diversity in multi-path fading while in non-collocated RAs, thespectral efficiency increase is due to diversity exploitation in both shadowingand multi-path fading. Simulation results show that switched MRTD is mostadvantageous when the RAs provide comparable throughputs. Furthermore,when combined with multi-radio ARQ, MRTD significantly reduces packetloss and packet transmission delays. This is also shown in the specific radioaccesssimulation scenario where a delay sensitive voice service is studied. Inaddition, switched MRTD provides comparable gains to parallel MRTD interms of average packet transmission delay and packet loss, while using lessradio resources. In all cases, it is concluded that maximum performance isconditioned on the reporting delays of the channel quality indicator (CQI).Reporting delays of CQI that are half the channel coherence time render sucha complex MRTD mechanism less effective.

QC 20130531

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Jin, Fan. "Resource allocation for heterogeneous radio-frequency and visible-light networks". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/381300/.

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In recent years, mobile data traffic demands have been increased exponentially, and the conventional cellular systems can no longer support the capacity demands. A potential solution for meeting such demands may be Heterogeneous Network (HetNet) techniques. A HetNet may integrate diverse radio access technologies (RAT) such as UMTS Terrestrial Radio Access Networks (UTRAN), GSM/EDGE Radio Access and Network (GERAN), Wireless Local Area Network (WLAN) as well as possibly Visible Light Communication (VLC) networks. The improved channel gain of the HetNet techniques is achieved by employing the small cells and by reduced transmission distance. However, the deployment of HetNet techniques also impose several technical challenges, for example the interference management, handovers, resource management and modelling of HetNets. A HetNet relies on multiple types of access nodes in a wireless network. These access nodes can use either the same technology or different technologies. When the access nodes employ the same technology and use the same frequency band, a major problem is the Co-Channel-Interference (CCI) between these access nodes. We firstly investigate a Radio-Frequency (RF) based HetNet in Chapter 3, which is constituted by the macrocells and the femtocells. More explicitly, the impacts of femtocells on traditional macrocells are studied, when the macrocells are relying on Fractional Frequency Reuse (FFR). The design, performance analysis and optimization problems of this FFR aided two-tier HetNet is investigated. We found the advantage of FFR eroded in dense femtocell scenarios and the optimized network tends to become a Unity Frequency Reuse (UFR) aided system. In order to mitigate the cross-tier interference, we proposed a statics spectrum allocation scheme, namely Swapping Spectrum Access (SSA). Both the Outage Probability (OP) of femtocell Mobile Terminals (MTs) in cell centre region and that of the macrocell MTs in the cell edge region is reduced by the proposed SSA. The optimized network using our SSA is more robust to the detrimental impact of femtocells. Another constitution of a HetNet may rely on integrating different technologies of wireless communication networks. We focus on our attentions on a HetNet composing by a RF femtocell and a VLC network in Chapter 4 and 5. An important component of this architecture is its Resource Management (RM). We investigate the Resource Allocation (RA) problems, under the diverse quality of service (QoS) requirements in terms of data rate, fairness and the statistical delay requirements. Two types of MTs, multi-homing MTs and multi-mode MTs are considered, where multi-homing MTs have the capability of aggregating resources from different networks, while the multi-mode MTs always select a single network for their connection. We proposed a sub-optimal decentralized method for solving the RA problems of both the multi-homing MTs and multi-mode MTs. The simulation results confirm the conceived method is capable of satisfying the QoS requirements. Furthermore, we employ more sophisticated transmission strategies for the VLC network and study their performance in Chapter 5. Again, the RA problems of the HetNet relying on different transmission strategies are investigated.

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Dandachi, Ghina. "Multihoming in heterogeneous wireless networks". Thesis, Evry, Institut national des télécommunications, 2017. http://www.theses.fr/2017TELE0014/document.

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Les réseaux mobiles de la cinquième génération (5G) sont conçus pour introduire de nouveaux services nécessitant des débits de données extrêmement hauts et une faible latence. 5G sera un changement de paradigme qui comprend des réseaux hétérogènes densifiés, des réseaux d'accès radio virtualisés, des fréquences porteuses à ondes millimétrées et des densités de périphériques très élevées. Cependant, contrairement aux générations précédentes, 5G sera un réseau holistique, intégrant n'importe quelle nouvelle technologie radio avec les technologies LTE et WiFi existant. Dans ce contexte, on se concentre sur de nouvelles stratégies d'allocation de ressources capables de bénéficier du multihoming dans le cas d'accès double au réseau. On modélise ces algorithmes au niveau du flux et analyse leurs performances en termes de débit, de stabilité du système et d'équité entre différentes catégories d'utilisateurs. On se concentre tout d'abord sur le multihoming dans les réseaux hétérogènes LTE/WiFi. On considère les allocations centrées sur le réseau où un planificateur central effectue des allocations d'équité proportionnelle (PF) locale et globale pour différentes classes d'utilisateurs, utilisateurs individuels (single-homed) et multi-domiciliés (multihomed). Par rapport à un modèle de référence sans multihoming, on montre que les deux stratégies améliorent la performance et la stabilité du système, au détriment d'une plus grande complexité pour la stratégie PF globale. On étudie également les stratégies d'allocation centrées sur l'utilisateur, dans lesquelles les utilisateurs multihomed décident la partition de la demande d'un fichier en utilisant soit la maximisation du débit crête, soit la stratégie assistée par réseau. On montre que cette dernière stratégie maximise le débit moyen dans l'ensemble du réseau. On montre également que les stratégies centrées sur le réseau permettent d'obtenir des débits de données plus élevés que ceux centrés sur l'utilisateur. Ensuite, on se concentre sur les réseaux d'accès radio virtuels (V-RAN) et en particulier sur l'allocation de multi-ressources. On étudie la faisabilité de la virtualisation sans diminuer ni la performance des utilisateurs, ni la stabilité du système. On considère un réseau hétérogène 5G composé de cellules LTE et mm-wave afin d'étudier comment les réseaux hauts fréquence peuvent augmenter la capacité du système. On montre que la virtualisation du réseau est réalisable sans perte de performance lors de l'utilisation de la stratégie « dominant resource fairness » (DRF). On propose une stratégie d'allocation en deux phases (TPA) qui montre un indice d'équité plus élevé que DRF et une stabilité du système plus élevée que PF. On montre également des gains importants apportés par l'adoption des fréquences mm-wave au lieu de WiFi. Finalement, on considère l'efficacité énergétique et compare les stratégies DRF et TPA avec une stratégie éconergétique basée sur l'algorithme de Dinklebach. Les résultats montrent que la stratégie éconergétique dépasse légèrement DRF et TPA à charge faible ou moyenne en termes de débit moyen plus élevé avec une consommation d'énergie comparable, alors qu'elle les surpasse à une charge élevée en termes de consommation d'énergie moins élevée. Dans ce cas de charge élevée, DRF surpasse TPA et la stratégie éconergétique en termes de débit moyen. En ce qui concerne l'indice d'équité de Jain, TPA réalise l'indice d'équité le plus élevé parmi d'autres stratégies
Fifth generation mobile networks (5G) are being designed to introduce new services that require extreme broadband data rates and utlra-reliable latency. 5G will be a paradigm shift that includes heterogeneous networks with densification, virtualized radio access networks, mm-wave carrier frequencies, and very high device densities. However, unlike the previous generations, it will be a holistic network, tying any new 5G air interface and spectrum with the currently existing LTE and WiFi. In this context, we focus on new resource allocation strategies that are able to take advantage of multihoming in dual access settings. We model such algorithms at the flow level and analyze their performance in terms of flow throughput, system stability and fairness between different classes of users. We first focus on multihoming in LTE/WiFi heterogeneous networks. We consider network centric allocations where a central scheduler performs local and global proportional fairness (PF) allocations for different classes of users, single-homed and multihomed users. By comparison with a reference model without multihoming, we show that both strategies improve system performance and stability, at the expense of more complexity for the global PF. We also investigate user centric allocation strategies where multihomed users decide the split of a file using either peak rate maximization or network assisted strategy. We show that the latter strategy maximizes the average throughput in the whole network. We also show that network centric strategies achieve higher data rates than the user centric ones. Then, we focus on Virtual Radio Access Networks (V-RAN) and particularly on multi-resource allocation therein. We investigate the feasibility of virtualization without decreasing neither users performance, nor system's stability. We consider a 5G heterogeneous network composed of LTE and mm-wave cells in order to study how high frequency networks can increase system's capacity. We show that network virtualization is feasible without performance loss when using the dominant resource fairness strategy (DRF). We propose a two-phase allocation (TPA) strategy which achieves a higher fairness index than DRF and a higher system stability than PF. We also show significant gains brought by mm-wave instead of WiFi. Eventually, we consider energy efficiency and compare DRF and TPA strategies with a Dinklebach based energy efficient strategy. Our results show that the energy efficient strategy slightly outperforms DRF and TPA at low to medium load in terms of higher average throughput with comparable power consumption, while it outperforms them at high load in terms of power consumption. In this case of high load, DRF outperforms TPA and the energy efficient strategy in terms of average throughput. As for Jain's fairness index, TPA achieves the highest one

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Khaled, Haitham El-Mohamdy. "Energy and throughput efficient strategies for heterogeneous future communication networks". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2021. https://ro.ecu.edu.au/theses/2418.

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As a result of the proliferation of wireless-enabled user equipment and data-hungry applications, mobile data traffic has exponentially increased in recent years.This in-crease has not only forced mobile networks to compete on the scarce wireless spectrum but also to intensify their power consumption to serve an ever-increasing number of user devices. The Heterogeneous Network (HetNet) concept, where mixed types of low-power base stations coexist with large macro base stations, has emerged as a potential solution to address power consumption and spectrum scarcity challenges. However, as a consequence of their inflexible, constrained, and hardware-based configurations, HetNets have major limitations in adapting to fluctuating traffic patterns. Moreover, for large mobile networks, the number of low-power base stations (BSs) may increase dramatically leading to sever power consumption. This can easily overwhelm the benefits of the HetNet concept. This thesis exploits the adaptive nature of Software-defined Radio (SDR) technology to design novel and optimal communication strategies. These strategies have been designed to leverage the spectrum-based cell zooming technique, the long-term evolution licensed assisted access (LTE-LAA) concept, and green energy, in order to introduce a novel communication framework that endeavors to minimize overall network on-grid power consumption and to maximize aggregated throughput, which brings significant benefits for both network operators and their customers. The proposed strategies take into consideration user data demands, BS loads, BS power consumption, and available spectrum to model the research questions as optimization problems. In addition, this thesis leverages the opportunistic nature of the cognitive radio (CR) technique and the adaptive nature of the SDR to introduce a CR-based communication strategy. This proposed CR-based strategy alleviates the power consumption of the CR technique and enhances its security measures according to the confidentiality level of the data being sent. Furthermore, the introduced strategy takes into account user-related factors, such as user battery levels and user data types, and network-related factors, such as the number of unutilized bands and vulnerability level, and then models the research question as a constrained optimization problem. Considering the time complexity of the optimum solutions for the above-mentioned strategies, heuristic solutions were proposed and examined against existing solutions. The obtained results show that the proposed strategies can save energy consumption up to 18%, increase user throughput up to 23%, and achieve better spectrum utilization. Therefore, the proposed strategies offer substantial benefits for both network operators and users.

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Tian, Hongqiao. "Dynamic spectrum decision in multi-channel cognitive radio networks with heterogeneous services". IEEE, 2015. http://hdl.handle.net/1993/31504.

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We study a dynamic channel selection framework for cognitive radio networks (CRNs) which support both delay sensitive and best effort services. Unlike existing works in the literature, we consider the effect of heterogeneous radio frequency characteristics and heterogeneous primary user activities on channel selection in multi-channel CRNs. Optimal spectrum decision policies are obtained to achieve minimum delay using dynamic programming techniques, such as Markov decision process (MDP) and reinforcement learning, under different assumptions. To address the computational complexity issue in the MDP solutions, a myopic scheme is proposed based on the estimated packet sojourn time.
October 2016

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35

Chen, Xue. "Efficient Device to Device Communication Underlaying Heterogeneous Networks". DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/4673.

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Device-to-Device communications have the great potential to bring significant performance boost to the conventional heterogeneous network by reusing cellular resources. In cellular networks, Device-to-Device communication is defined as two user equipments in a close range communicating directly with each other without going through the base station, thus offloading cellular traffic from cellular networks. In addition to improve network spectral efficiency, D2D communication can also improve energy efficiency and user experience. However, the co-existence of D2D communication on the same spectrum with cellular users can cause severe interference to the primary cellular users. Thus the performance of cellular users must be assured when supporting underlay D2D users. In this work, we have investigated cross-layer optimization, resource allocation and interference management schemes to improve user experience, system spectral efficiency and energy efficiency for D2D communication underlaying heterogeneous networks. By exploiting frequency reuse and multi-user diversity, this research work aims to design wireless system level algorithms to utilize the spectrum and energy resources efficiently in the next generation wireless heterogeneous network.

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36

Koutlia, Aikaterini. "Radio resource management strategies for interference mitigation in 4G heterogeneous wireless networks". Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/395202.

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The new era of mobile communications is dictated by the user demand for robust and high speed connections, data hungry applications and seamless connectivity. Operators and researchers all over the world are challenged to fulfill these requirements by providing enhanced coverage, increased capacity and efficient usage of the scarce spectrum. The introduction of the fourth generation systems (4G), LTE and LTE-A, have set the initiative for a technology evolution that offers new possibilities and is able to satisfy the user requirements and overcome the imposed challenges. However, and despite the improvements brought by the LTE and LTE-A systems, there are certain constraints that still need to be surpassed. LTE for example adopts innovating technologies, such as Orthogonal Frequency Division Multiplexing Access (OFDMA) that improves the spectral efficiency and reduces the Intra-Cell Interference. Nevertheless, Inter-Cell Interference (ICI) remains a constraining factor that can degrade the system capacity and limit the overall performance of the network. On that respect, Inter-Cell Interference Coordination (ICIC) techniques are adopted with target the interference mitigation. One of the limitations of these techniques is that follow static configurations lacking of flexibility and adaptation on network changes. Moreover, LTE-A employs enhanced and new techniques and involves alternative strategies. A promising solution lies on the introduction of Heterogeneous Networks (HetNets), which are networks that include low power small cells under the already existing macro cellular network and exploit several other technologies, such as WiFi. HetNets can further improve the network capacity, enhance the coverage and provide higher speed data transfer. However, due to the heterogeneous nature of the network, traditional methods for the user association, resource allocation and interference mitigation may not always be suitable since their design was based on homogeneous deployments. As such, new and enhanced methods are introduced, such as enhanced ICIC (eICIC), with their accompanied requirements and challenges. Motivated by the abovementioned aspects, this thesis has been focused on the study of ICIC and eICIC schemes, the identification of the related challenges, the enhancement of existing schemes and the proposal of novel solutions. In particular in the initial stages of the work, ICIC techniques have been studied and analyzed. A distributed algorithm that performs dynamic channel allocation has been developed for homogeneous deployments and extended later on to include heterogeneous networks. The solution has been optimized with the use of the Gibbs Sampler, while the setting of algorithm related parameters has been addressed through a detailed analysis. Moreover, a possible implementation of the solution has been presented in detail. The efficiency of the proposed schemes has been demonstrated through simulations and comparisons with benchmark schemes. In the next steps, the work has targeted eICIC techniques with purpose the investigation and analysis of the main constraining issues related to the user association, resource management and interference mitigation. Novel eICIC schemes that aim a better resource management and the overall capacity improvement have been developed and presented in detail, while the performance of the solutions has been shown through simulations and comparisons with reference schemes. Moreover, an optimized eICIC solution has been implemented based on genetic algorithms. Simulation results and comparisons with reference schemes have demonstrated the efficiency of the solution, while the selected configurations are discussed and analyzed.
La nueva era de las comunicaciones móviles viene marcada por la demanda de los usuarios por conseguir conexiones robustas de alta velocidad que permitan soportar aplicaciones de datos de elevados requerimientos. El cumplimiento de estos requisitos conlleva la necesidad de mejorar la cobertura, incrementar la capacidad y utilizar el espectro eficientemente. La introducción de los sistemas de cuarta generación (4G), LTE y LTE-A, ha dado lugar a una tecnología que ofrece nuevas posibilidades y es capaz de satisfacer las necesidades de los usuarios y superar los retos impuestos. Sin embargo, y a pesar de las mejoras introducidas por estos sistemas, hay ciertas limitaciones que todavía tienen que ser superadas. LTE, por ejemplo, adopta tecnologías tales como OFDMA que mejora la eficiencia espectral y reduce la interferencia intracelular. Sin embargo, la interferencia intercelular (ICI) sigue siendo un factor limitante que puede degradar la capacidad del sistema y limitar el rendimiento global de la red. En ese sentido, se requieren técnicas de coordinación de interferencias intercelulares (ICIC) con el objetivo de mitigar dicha interferencia. Una de las limitaciones de estas técnicas es que siguen configuraciones estáticas que carecen de flexibilidad y capacidad de adaptación a los cambios de la red. Por otra parte, LTE-A introduce nuevas mejoras, como las redes heterogéneas (HetNets), que son redes que incluyen pequeñas células de baja potencia conjuntamente con la red macrocellular y también pueden explotar diferentes tecnologías, como WiFi. Las HetNets pueden mejorar aún más la capacidad de la red, mejorar la cobertura y facilitar la transferencia de datos de mayor velocidad. Sin embargo, debido a la naturaleza heterogénea de la red, los métodos tradicionales para la asociación de usuarios, asignación de recursos y reducción de la interferencia pueden no ser siempre adecuados, ya que su diseño se basó en despliegues homogéneos. En este sentido, es preciso introducir técnicas mejoradas de ICIC, denominadas en inglés eICIC (enhanced-ICIC), que involucran nuevos requerimientos y retos. En base a todos estos aspectos, esta tesis se ha centrado en el estudio de los sistemas de ICIC y eICIC en redes celulares, incluyendo la identificación de los retos relacionados con la mejora de los sistemas existentes y la propuesta de soluciones novedosas. En particular, en las etapas iniciales de la tesis se han estudiado y analizado las técnicas ICIC, y se ha desarrollado un algoritmo distribuido que realiza la asignación dinámica de canales para despliegues homogéneos, ampliándose posteriormente para su utilización en redes heterogéneas. La solución opera de forma optimizada mediante el uso de la técnica denominada Gibbs Sampler, mientras que el ajuste de parámetros relacionado con el algoritmo se ha abordado a través de un análisis detallado basado en simulaciones. Por otra parte, una posible implementación de la solución se ha presentado en detalle. La eficiencia de los esquemas propuestos se ha demostrado a través de simulaciones y comparaciones con sistemas de referencia. En los siguientes pasos, el trabajo se ha centrado en las técnicas eICIC con el propósito de investigar y analizar los principales problemas relacionadas con la asociación de usuarios, gestión de recursos y mitigación de la interferencia. A partir de aquí se han desarrollado nuevos esquemas de eICIC que tienen como objetivo una mejor gestión de los recursos y la mejora general de la capacidad. El rendimiento de las soluciones se ha demostrado a través de simulaciones y comparaciones con sistemas de referencia. Por otra parte, se ha propuesto una solución eICIC optimizada basada en algoritmos genéticos. La eficacia de dicha solución se ha demostrado mediante simulaciones, a la vez que se han analizado las diferentes configuraciones seleccionadas por el proceso de optimización.

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37

Raiss, El Fenni Mohammed. "Opportunistic spectrum usage and optimal control in heterogeneous wireless networks". Phd thesis, Université d'Avignon, 2012. http://tel.archives-ouvertes.fr/tel-00907120.

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The present dissertation deals with how to use the precious wireless resources that are usually wasted by under-utilization of networks. We have been particularly interested by all resources that can be used in an opportunistic fashion using different technologies. We have designed new schemes for better and more efficient use of wireless systems by providing mathematical frameworks. In the first part, We have been interested in cognitive radio networks, where a cellular service provider can lease a part of its resources to secondary users or virtual providers. In the second part, we have chosen delay-tolerant networks as a solution to reduce the pressure on the cell traffic, where mobile users come to use available resources effectively and with a cheaper cost. We have focused on optimal strategy for smartphones in hybrid wireless networks. In the last part, an alternative to delay-tolerant networks, specially in regions that are not covered by the cellular network, is to use Ad-hoc networks. Indeed, they can be used as an extension of the coverage area. We have developed a new analytical modeling of the IEEE 802.11e DCF/EDCF. We have investigated the intricate interactions among layers by building a general cross-layered framework to represent multi-hop ad hoc networks with asymmetric topology and traffic

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38

Mahmood, Nurul Huda. "Interference Analysis and Management with Applications in Heterogeneous Small-cell Cognitive Radio Networks". Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20013.

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This thesis examines interference modeling and management in small cell cognitive radio networks. A generalized unified statistical model is presented for the interference from a heterogeneous next generation network at a target receiver located at the centre of a cell. The derived model is then applied in devising a simple distributed power allocation algorithm for the next generation network nodes, and in the various performance analyses of the the coexisting systems. Cooperative communication improves the outage performance and coverage of wireless links under certain channel conditions, but is not spectrally efficient when channel conditions are favorable. A hybrid cooperation technique that can reap the diversity benefits of cooperative communication without sacrificing the multiplexing gain is proposed, and the performance of an interference temperature constrained cognitive radio network employing the proposed cooperation technique is analyzed. Next, a formulation of the power allocation problem in the cognitive interference channel is presented whereby the interference margin at the primary receivers are seen as resources to be shared optimally. A relative rate utility based power allocation algorithm that is shown to achieve favorable sum throughput is then proposed. Finally, the thesis investigates various interference coordination techniques for multi antenna cognitive radio users coexisting with multiple primary users under a restricted interference temperature constraint. Knowledge of the zero forcing beamforming techniques and the interference alignment schemes are applied to satisfy the restricted interference temperature constraint at the primary receivers while supporting significant sum rate at the secondary system.

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39

Changyan, Yi. "Auction-based Spectrum Sharing in Multi-Channel Cognitive Radio Networks with Heterogeneous Users". IEEE Transactions on Vehicular Technology, 2014. http://hdl.handle.net/1993/23943.

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Dynamic spectrum access based on cognitive radio has been regarded as a prospective solution to improve spectrum utilization for wireless communications. By considering the allocation efficiency, fairness, and economic incentives, spectrum marketing has been attracting more and more attentions in recent years. In this thesis, we focus on one of the most effective spectrum marketing methods, i.e., auction approach, in multi-channel cognitive radio networks. After presenting some fundamentals and related works, we begin our discussion in a recall-based auction system where buyers have various service requirements and the seller could recall some sold items after the auction to deal with a sudden increase of its own demand. Both single-winner and multi-winner auctions are designed and analyzed. In addition, we also consider the heterogeneity of radio resource sellers and formulate a framework of combinatorial spectrum auction. With theoretical analyses and simulation results, we show that our proposed algorithms can improve spectrum utilization while satisfy the heterogeneous requirements of different wireless users.

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40

Martins, Moraes Thiago [Verfasser]. "Advanced Radio Resources Management for Relaying in Heterogeneous Mobile Networks / Thiago Martins Moraes". München : Verlag Dr. Hut, 2015. http://d-nb.info/1080754660/34.

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41

Araújo, Moreira Nicolas de. "On heterogeneous networks under non-Gaussian interferences : experimental and theoretical aspects". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I041/document.

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L’Internet des Objets représente un défi technique pour la communication 5G à cause de son hétérogénéité caractéristique : la bande 2.4 GHz ISM, par exemple, est partagée entre différents types de technologies, comme Wifi, Bluetooth et Zigbee. En plus de la perte de qualité de communication, des études récentes montrent que l’interférence augmente de façon significative la consommation d’énergie. Donc, traiter l’interférence devient une tâche importante pour assurer la réussite de la transmission de données. Cette thèse approche deux aspects différents des réseaux hétérogènes. La première partie présente une étude expérimentale sur la nature de l’interférence entre dispositifs IEEE 802.11 et 802.15.4, ses impacts dans la fiabilité de la communication et propose une description statistique. La conclusion principale est que, dans ce contexte, l’interférence présente un comportement non-Gaussien, plus précisément, impulsif. Des travaux théoriques récents alliés avec ces résultats expérimentaux montrent que la distribution α-stable est plus convenable pour représenter bruits impulsives. Cela signifie que, une fois optimal, les architectures de communication classiques basé sur assomption Gaussienne, particulièrement la méthode des moindres carrés et le récepteur linéaire, ne sont plus optimales et présentent une perte de performance significative. La deuxième partie présente une architecture MIMO basé sur codage Alamouti, estimation de canal supervisée basé sur méthode Least Absolute Deviation et récepteur p-norme avec une estimation de p. L’architecture proposée présente une performance supérieure au méthode classique
Internet of Things represents a technical challenge for 5G communications due to is characteristic heterogeneity: the 2.4 GHz ISM band, for example, is shared between different kind of technologies, such Wifi, Bluetooth and Zigbee. In addition to the loss of quality of communication, recent studies show that interference increases significantly the energy consumption. So, dealing with interference becomes an important task to ensure successfull data transmission. The present thesis approaches two aspects of heterogeneous networks. The first part presents an experimental study on the nature of interference between IEEE 802.11 and IEEE 802.15.4 devices, its impacts on the communication reliability and proposes an statistical description of it. The main conclusion of this part is that, on this context, the interference may present a non-Gaussian behavior, more precisely, an impulsive behavior. Recent theoretical works allied with these experimental results show that the α-stable distribution is more adequate to represent impulsive noises. It means that the, once optimal, classical communication architectures based on the Gaussian assumption, particularly the Least Squares based channel estimation and linear receiver, are not optimal anymore present a significant loss of performance. The second part presents a robust MIMO architecutre based on Alamouti coding, supervised channel estimation based on Least Absolute Deviation and p-norm receiver with an estimator for p. The proposed approach outperforms the classical method

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42

Falconetti, Laetitia Verfasser], Gerd [Akademischer Betreuer] [Ascheid i Rudolf [Akademischer Betreuer] Mathar. "Energy efficient radio resource management in heterogeneous networks / Laetitia Falconetti ; Gerd Ascheid, Rudolf Mathar". Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1129875695/34.

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Calabuig, Soler Daniel. "Common Radio Resource Management Strategies for Quality of Service Support in Heterogeneous Wireless Networks". Doctoral thesis, Universitat Politècnica de València, 2010. http://hdl.handle.net/10251/7348.

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Hoy en día existen varias tecnologías que coexisten en una misma zona formando un sistema heterogéneo. Además, este hecho se espera que se vuelva más acentuado con todas las nuevas tecnologías que se están estandarizando actualmente. Hasta ahora, generalmente son los usuarios los que eligen la tecnología a la que se van a conectar, ya sea configurando sus terminales o usando terminales distintos. Sin embargo, esta solución es incapaz de aprovechar al máximo todos los recursos. Para ello es necesario un nuevo conjunto de estrategias. Estas estrategias deben gestionar los recursos radioeléctricos conjuntamente y asegurar la satisfacción de la calidad de servicio de los usuarios. Siguiendo esta idea, esta Tesis propone dos nuevos algoritmos. El primero es un algoritmo de asignación dinámica de recusos conjunto (JDRA) capaz de asignar recursos a usuarios y de distribuir usuarios entre tecnologías al mismo tiempo. El algoritmo está formulado en términos de un problema de optimización multi-objetivo que se resuelve usando redes neuronales de Hopfield (HNNs). Las HNNs son interesantes ya que se supone que pueden alcanzar soluciones sub-óptimas en cortos periodos de tiempo. Sin embargo, implementaciones reales de las HNNs en ordenadores pierden esta rápida respuesta. Por ello, en esta Tesis se analizan las causas y se estudian posibles mejoras. El segundo algoritmo es un algoritmo de control de admisión conjunto (JCAC) que admite y rechaza usuarios teniendo en cuenta todas las tecnologías al mismo tiempo. La principal diferencia con otros algorimos propuestos es que éstos últimos toman las dicisiones de admisión en cada tecnología por separado. Por ello, se necesita de algún mecanismo para seleccionar la tecnología a la que los usuarios se van a conectar. Por el contrario, la técnica propuesta en esta Tesis es capaz de tomar decisiones en todo el sistema heterogéneo. Por lo tanto, los usuarios no se enlazan con ninguna tecnología antes de ser admitidos.
Calabuig Soler, D. (2010). Common Radio Resource Management Strategies for Quality of Service Support in Heterogeneous Wireless Networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/7348
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44

Falconetti, Laetitia [Verfasser], Gerd [Akademischer Betreuer] Ascheid i Rudolf [Akademischer Betreuer] Mathar. "Energy efficient radio resource management in heterogeneous networks / Laetitia Falconetti ; Gerd Ascheid, Rudolf Mathar". Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1129875695/34.

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45

Tabany, M. R. "Downlink radio resource management techniques for voice over LTE QoS and QoE over heterogeneous wireless networks". Thesis, University of Reading, 2016. http://centaur.reading.ac.uk/69061/.

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Long Term Evolution (LTE) is the Fourth Generation (4G) mobile broadband technology. Third-Generation Partnership Project (3GPP) has finalized its standardization in Release 8 technical specifications (R8). As users’ demand for higher data rate continues to rise, LTE and its ability to cost effectively provide fast, highly responsive mobile data services, a scalable bandwidth and a reduced latency will become ever more important. Nevertheless, The Evolved Packet Core (EPC) of the LTE is all-IP Packet-Switched (PS) core networks that lack a native support for Circuit-Switched (CS) services. This introduces a problem of how to provide PS voice services in LTE networks and how to support a voice service quality of at least efficient as a voice service in 3G mobile technologies and the service continuity of voice service to different radio access network toward a heterogeneous wireless network. This thesis investigates the role of the Radio Recourse Management (RRM) techniques in improving the end-user experience and the service quality of Voice over LTE (VoLTE) application service. The thesis explores the possible proposed solutions to provide voice over LTE networks and suggests the required recommendations in regards to voice over LTE deployment based on one of the proposed techniques. A baseline simulation of LTE network is designed to give a clear understanding of the state of the art of VoLTE QoS and QoE, which then improved to cover scenarios where the wireless network congested under different load conditions, different types of traffic and different LTE bandwidths. In the literature, most of the studies were focused on the single Radio Access Technology (RAT) of Evolved Universal Terrestrial Radio Access Network (E-UTRAN), where the end-to-end performance of VoLTE of multi-RAT over a Heterogeneous wireless Network (HetNet) has been less investigated. The future of wireless networks is going to be heterogeneous. The continuity of the service when LTE users with active real time application services such as VoLTE running on their smart phones move between different mobile networks is the major concern in the future of these networks. In addition, there is a common issue of a lack of considering high mobility, and frequent and unnecessary handovers in these networks. VoLTE end-to-end delay is an important service quality factor, which needs to be maintain carefully, otherwise can severely affect the voice user experience. By exploiting the RRM techniques, the impact of this delay is limited, and the overall LTE network performance is further enhanced. To begin with, this study proposes a new, highly flexible Delay-Aware QoS Scheme (DAQS) for 3GPP LTE networks which is then critically simulated, and examined. The proposed scheme uses the idea of QCI-DSCP (QoS Class Identifier-Differentiated Services Code Point) mapping in the transport layer along with the queuing, scheduling on the LTE backhaul network to manage different application services with different requirements and provide an acceptable level of fairness between these services. The results reveal that the overall VoLTE end-to-end delay is remarkably reduced by approximately 35% compared to the baseline congested network scenario. FTP download and upload response time have both decreased while video conferencing traffic received increased by 30% on the price of a slight increase in LTE transport complexity. Handover delay is another factor, which investigated in this thesis. Packet transmission is disabled during the hard handover and network faces extra delay due to the interruption time that included in the process. The quality of service provided to the end-user is temporarily impaired and handover prediction is one emerging technique to mitigate this in Femtocell Home eNBs (HeNBs) with the unavoidable frequent handovers. This study proposes a mobility prediction scheme to help reduce VoLTE end-to-end delay and handover delay in the worst-case scenario of a mixed of femtocells and macrocells environment and under different UE velocities. The mobility prediction works based on user’s path and Reference Signal Received Power and Reference Signal Received Quality (RSRP and RSRQ) measurements. The results after applying the proposed prediction scheme show that the average handover delay is reduced significantly. Handover delay reduced by around 29% and VoLTE end-to-end delays kept within the standard recommendations. Regular movements resulted in 28% VoLTE end-to-end delay reduction and helped to maintain the desired VoLTE QoS. This study further proposes a novel DL hybrid-scheduling algorithm of Semi-Persistent Scheduling (SPS) and Talk-Spurt Scheduling (TSS) to reduce delay, Packet Loss Ratio (PLR) and increase capacity of VoLTE. This scheduling includes a novel work in terms of it is one of the few studies that introduce a complete implementation of end-to-end QoS over HetNet. The performance of the proposed scheme is compared with the performance of two relevant and well-known DL packet scheduling techniques, where the proposed DL scheduling algorithm outperforms them and provides a lower packet loss ratio, higher capacity and reduces VoLTE end-to-end delay accordingly.

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46

Maviel, Laurent. "Modélisation et simulation des réseaux sans fil hétérogènes et non-stationnaires : Application aux topologies de petites cellules". Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00942972.

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Les nouveaux services de télécommunication accessibles en mobilité entraînent une demande croissante de débit et amènent aux limites de capacités des réseaux actuels. Pour répondre à cette demande, les opérateurs cellulaires déploient de nouvelles technologies et densifient leurs réseaux en ajoutant des petites cellules, où les stations de base sont plus proches des utilisateurs. Compte tenu de la visibilité directe et de la faible hauteur des antennes, le canal de propagation des petites cellules est différent de celui des macro-cellules et les modèles stochastiques de canal existants ne sont plus adaptés. C'est dans ce contexte que se situe cette thèse, qui explore les problématiques de dynamique dans le canal de propagation et dans l'utilisation des ressources radio. Nous proposons dans une première partie de caractériser les dynamiques dans le canal de propagation de petite cellule en milieu extérieur. Cette caractérisation se base sur des prédictions déterministes, où une partie de l'environnement est généré de manière aléatoire afin de procéder à des études statistiques. Pour cela, nous mettons en place une plateforme de simulation, capable de générer des objets statiques, de les déplacer et de les prendre en compte dans des outils de prédiction de propagation adaptés aux petites cellules. Une phase de mesures de l'impact du trafic de véhicules sur la puissance du signal permet de valider les outils de propagation développés dans la plateforme. L'objectif de la deuxième partie de la thèse est d'évaluer l'impact de ces nouvelles topologies sur les performances des réseaux hétérogènes. Nous présentons un modèle hybride de propagation qui prend en compte les variations de signal dues au trafic de véhicules en combinant les approches déterministes et statistiques, pour avoir les avantages de résultats précis et d'un temps de calcul rapide. Ce modèle hybride est utilisé par la suite dans un processus de simulation de réseau cellulaire 3G LTE au niveau système, où nous évaluons l'impact du trafic de véhicules sur le débit maximal, la consommation d'énergie et le respect de la qualité de service.

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Dorni, Aljoša. "IEEE 802.11 Networks: MAC Protocols for Heterogeneous Multi-Antenna Scenarios and Software-Defined Radio PHY Layer Implementation". Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8538.

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2011/2012
The objective of this thesis is to discuss the performance achieved by IEEE 802.11 networks, considering in detail their simulation and experimental analysis, as well as the implementation aspects. The original contribution of this dissertation involves three main research fields within the context of distributed wireless networks: the experimental and theoretical analysis of IEEE 802.11e networks in presence of quality of service mechanisms, the development and the simulation of backward compatible medium access control protocols in presence of smart antenna systems, and, finally, the implementation of the IEEE 802.11ag physical layer on software-defined radio platforms.
L’obiettivo di questa tesi è discutere le prestazioni ottenibili nelle reti IEEE 802.11, prendendo in considerazione sia la loro simulazione ed analisi sperimentale, sia gli aspetti implementativi. Il contributo originale di questa tesi include tre argomenti principali che riguardano le reti wireless distribuite: l’analisi sperimentale e teorica delle reti 802.11e che adottano meccanismi di qualità del servizio, lo sviluppo e la simulazione di schemi di accesso multiplo retrocompatibili basati sull’utilizzo di sistemi di antenne intelligenti, e, infine, l’implementazione su piattaforme software-defined radio del livello fisico 802.11ag.
XXV Ciclo
1980

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48

Centenaro, Marco. "On the Support of Massive Machine-to-Machine Traffic in Heterogeneous Networks and Fifth-Generation Cellular Networks". Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3426783.

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The widespread availability of many emerging services enabled by the Internet of Things (IoT) paradigm passes through the capability to provide long-range connectivity to a massive number of things, overcoming the well-known issues of ad-hoc, short-range networks. This scenario entails a lot of challenges, ranging from the concerns about the radio access network efficiency to the threats about the security of IoT networks. In this thesis, we will focus on wireless communication standards for long-range IoT as well as on fundamental research outcomes about IoT networks. After investigating how Machine-Type Communication (MTC) is supported nowadays, we will provide innovative solutions that i) satisfy the requirements in terms of scalability and latency, ii) employ a combination of licensed and license-free frequency bands, and iii) assure energy-efficiency and security.
La diffusione capillare di molti servizi emergenti grazie all’Internet of Things (IoT) passa attraverso la capacità di fornire connettività senza fili a lungo raggio ad un numero massivo di cose, superando le note criticità delle reti ad hoc a corto raggio. Questa visione comporta grandi sfide, a partire dalle preoccupazioni riguardo l’efficienza delle rete di accesso fino alle minacce alla sicurezza delle reti IoT. In questa tesi, ci concentreremo sia sugli standard di comunicazione a lungo raggio per l’IoT sia sulla ricerca di base per le reti IoT. Dopo aver analizzato come vengono supportate le comunicazioni Machine-to-Machine (M2M) oggi, forniremo soluzioni innovative le quali i) soddisfano i requisiti in termini di scalabilità e latenza, ii) utilizzano una combinazione di bande di frequenza licenziate e libere e iii) assicurano efficienza energetica e sicurezza.

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49

Sigwele, Tshiamo. "Energy Efficient Cloud Computing Based Radio Access Networks in 5G. Design and evaluation of an energy aware 5G cloud radio access networks framework using base station sleeping, cloud computing based workload consolidation and mobile edge computing". Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/16062.

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Fifth Generation (5G) cellular networks will experience a thousand-fold increase in data traffic with over 100 billion connected devices by 2020. In order to support this skyrocketing traffic demand, smaller base stations (BSs) are deployed to increase capacity. However, more BSs increase energy consumption which contributes to operational expenditure (OPEX) and CO2 emissions. Also, an introduction of a plethora of 5G applications running in the mobile devices cause a significant amount of energy consumption in the mobile devices. This thesis presents a novel framework for energy efficiency in 5G cloud radio access networks (C-RAN) by leveraging cloud computing technology. Energy efficiency is achieved in three ways; (i) at the radio side of H-C-RAN (Heterogeneous C-RAN), a dynamic BS switching off algorithm is proposed to minimise energy consumption while maintaining Quality of Service (QoS), (ii) in the BS cloud, baseband workload consolidation schemes are proposed based on simulated annealing and genetic algorithms to minimise energy consumption in the cloud, where also advanced fuzzy based admission control with pre-emption is implemented to improve QoS and resource utilisation (iii) at the mobile device side, Mobile Edge Computing (MEC) is used where computer intensive tasks from the mobile device are executed in the MEC server in the cloud. The simulation results show that the proposed framework effectively reduced energy consumption by up to 48% within RAN and 57% in the mobile devices, and improved network energy efficiency by a factor of 10, network throughput by a factor of 2.7 and resource utilisation by 54% while maintaining QoS.

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Haldar, Kuheli L. Ph D. "Efficient Quality of Service Provision Techniques in Next Generation Wireless Networks". University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397235725.

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