Dissertations / Theses: 'Device-to-device (D2D)'

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Kai, Yuan. "Resource management for cellular-assisted device-to-device (D2D) communications." Thesis, University of Kent, 2018. https://kar.kent.ac.uk/66874/.

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Device-to-Device (D2D) communication has become a promising candidate for future wireless communication systems to improve the system spectral efficiency, while reducing the latency and energy consumption of individual communication. With the assistance of cellular network, D2D communications can greatly reduce the transmit distance by utilizing the spatial dispersive nature of ever increasing user devices. Further, substantial spectrum reuse gain can be achieved due to the short transmit distance of D2D communication. It, however, significantly complicates the resource management and performance analysis of D2D communication underlaid cellular networks. Despite an increasing amount of academic attention and industrial interests, how to evaluate the system performance advantages of D2D communications with resource management remains largely unknown. On account of the proximity requirement of D2D communication, the resource management of D2D communication generally consists of admission access control and resource allocation. Resource allocation of cellular assisted D2D communications is very challenging when frequency reuse is considered among multiple D2D pairs within a cell, as intense inter D2D interference is difficult to tackle and generally causes extremely large amount of signaling overheads for channel state information (CSI) acquisition. Hence, the first part of this thesis is devoted to the resource allocation of cellular assisted D2D communication and the performance analysis. A novel resource allocation scheme for cellular assisted D2D communication is developed with low signaling overhead, while maintaining high spectral efficiency. By utilizing the spatial dispersive nature of D2D pairs, a geography-based sub-cell division strategy is proposed to group the D2D pairs into multiple disjoint clusters, and sub-cell resource allocation is performed independently for the D2D pairs within each sub-cell without the need of any prior knowledge of inter D2D interference. Under the proposed resource allocation scheme, tractable approximation for the inter D2D interference modeling is obtained and a computationally efficient expression for the average ergodic sum capacity of the cell is derived. The expression further allows us to obtain the optimal number of sub-cells that maximizes the average ergodic sum capacity of the cell. It is shown that with small CSI feedback, the system capacity/spectral efficiency can be improved significantly by adopting the proposed resource allocation scheme, especially in dense D2D deployment scenario. The investigation of use cases for cellular assisted D2D communication is another important topic which has direct effect on the performance evaluation of D2D communication. Thanks to the spatial dispersive nature of devices, D2D communication can be utilized to harvest the vast amount of the idle computation power and storage space distributed at the devices, which yields sufficient capacities for performing computation-intensive and latency-critical tasks. Therefore, the second part of this thesis focuses on the D2D communication assisted Mobile Edge Computing (MEC) network. The admission access control of D2D communication is determined by both disciplines of mobile computing and wireless communications. Specifically, the energy minimization problem in D2D assisted MEC networks is addressed with the latency constraint of each individual task and the computing resource constraint of each computing entity. The energy minimization problem is formed as a two-stage optimization problem. At the first stage, an initial feasibility problem is formed to maximize the number of executed tasks, and the global energy minimization problem is tackled in the second stage while maintaining the maximum number of executed tasks. Both of the optimization problems in two stages are NP-hard, therefore a low-complexity algorithm is developed for the initial feasibility problem with a supplementary algorithm further proposed for energy minimization. Simulation results demonstrate the near-optimal performance of the proposed algorithms and the fact that the number of executed tasks is greatly increased and the energy consumption per executed task is significantly reduced with the assistance of D2D communication in MEC networks, especially in dense user scenario.

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Chevillon, Romain. "Efficacité énergétique des communications Device-to-Device dans les réseaux hétérogènes." Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4072/document.

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L'objectif de cette thèse est l'étude de l'efficacité énergétique des communications D2D dans les réseaux hétérogènes. Nous proposons dans un premier temps d'analyser la consommation énergétique d'un réseau de trois appareils, puis introduisons une nouvelle topologie prenant en compte l'entropie de données, afin d'augmenter l'efficacité énergétique globale. Par la suite, nous étudions la consommation énergétique et l'influence des interférences sur une cellule dans le cas pratique d'une catastrophe naturelle. Nous introduisons alors un nouveau protocole d'allocation de ressources basé sur le clustering en Fuzzy C-Means. Nous utilisons ensuite des outils et métriques issus de la géométrie stochastique afin d'analyser et de comparer l'efficacité énergétique et spectrale au sein de plusieurs types de réseaux munis de communications D2D. Dans un deuxième temps, nous introduisons les notions d'antennes directionnelles avec des ondes millimétriques. Pour ce faire, nous évaluons l'influence du canal millimétrique et introduisons les concepts de blocage, et de modèles sectorisés d'antennes, à des fins mathématiques. L'utilisation d'ondes millimétriques, et plus particulièrement d'antennes directionnelles ULA, s'avère être un choix totalement opportun dans l'objectif premier de cette thèse qui est d'augmenter à la fois l'efficacité spectrale (donc le débit) et l'efficacité énergétique au sein d'un réseau hétérogène comprenant des communications D2D
The objective of this thesis is the study of the energy efficiency of D2D communications in heterogeneous networks. We first propose to analyze the energy consumption of a three device, then introduce a new topology taking into account the data entropy, in order to increase the overall energy efficiency. Subsequently, we study the energy consumption and the influence of interference in a cell for the use case of a natural disaster. We then introduce a new resource allocation protocol based on Fuzzy C-Means clustering. We then use tools and metrics from stochastic geometry to analyze and compare energy and spectral efficiency among multiple types of networks comprising D2D communications. The first study is done on a network in which the cellular and WiFi resources are shared. In a second step, we introduce the notions of directional antennas with millimeter waves. To do this, we evaluate the influence of the mmWave channel and introduce the concepts of blocking, and sectored models of antennas, for mathematical purposes. The use of millimeter waves, and more particularly ULA directional antennas, proves to be a totally appropriate choice in the primary objective of this thesis, which is to increase both the spectral efficiency (therefore the bit rate) and the energy efficiency within a heterogeneous network including D2D communications

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Li, Yujin. "Mobility and Traffic Correlations in Device-to-Device (D2D) Communication Networks." Thesis, North Carolina State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3690209.

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Bertier, Clément. "Quantification in Device-to-Device Networks : from Link Estimation to Graph Utility." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS250.

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Les communications d'appareil à appareil (D2D) sont utiles dans plusieurs domaines, e.g. le déléstage mobile, car elles ne coûtent qu’une fraction du prix d’une communication cellulaire. Dans cette thèse, nous soutenons que la compréhension de l'utilité potentielle derrière les communications directes est la clé pour quantifier les réseaux de contact. Tout d'abord, nous considérons le problème de l'estimation de l'importance d'un nœud dans de grandes topologies dynamiques. Nous proposons une approche nouvelle pour estimer les centralités à partir d'une base de données préétablie, où l'estimation est basée sur les coordonnées géographiques du nœud au lieu de l'identifiant du nœud. Deuxièmement, nous quantifions la valeur des liens directs grâce à une campagne de mesure expérimentale via Android. Nous proposons un modèle pour estimer la limite supérieure du débit D2D en fonction de la distance entre les appareils. Troisièmement, nous étudions les différences entre la quantification traditionnelle d'un contact et notre modèle. Entre autres résultats, nous révélons que lorsque l'on considère un débit adaptatif en fonction de la distance entre deux appareils, l'échange de données longue distance représente plus de 50% du total des données échangées dans l'ensemble du réseau. Nous proposons un outil pour extraire le volume de données obtenues à partir de traces mobilité
Device-to-device (D2D) communications are valuable in several domains, such as data offloading and diffusion, as their cost is only a fraction of what regular cellular communication would have. In this thesis, we argue that understanding the potential utility behind direct communications is key to quantifying the realization of contact networks. We tackle related questions from two distinct, yet complementary contributions. Firstly, we consider the problem of estimating the importance of a node in large dynamic topologies. We propose a novel approach to estimate centralities based on a pre-established database, where the estimation is based on the geographical coordinates of the node instead of the identifier of the node. Doing so enables us to estimate the centrality of a node for a fraction of the computational cost. Secondly, we quantify the value of direct links through an experimental measurement campaign. Using an Android tool of our making, we derived a model to obtain an estimate of the upper-bound of D2D throughput based on the distance between the devices. Thirdly, we investigate the differences between the traditional quantification of a contact and the model extracted from our measurements campaigns. Among other results, we reveal that when considering an adaptive throughput according to the distance between two devices, the long-distance data-exchange makes up more than 50% of the total data exchanged in the entire network. We propose a tool to extract from mobility datasets the volume of data obtained, based on specific contact quantification strategies

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Ghazanfari, A. (Amin). "Coordinated beamforming and power control for network controlled Device-to-Device (D2D) communication." Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201401111003.

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Since the integration of data services into cellular communications, cellular operators are struggling to harness the overwhelming data traffic on their networks. Underlay Device-to-Device (D2D) communication is a new and promising paradigm which allows proximate mobile users to have direct communication over the cellular spectrum that may be reused by other cellular users in the same cell. This new paradigm is proposed to assist the cellular operators to deal with the booming demand of mobile users. Recent studies have shown that underlay D2D communication significantly increases the cellular network capacity, and enables cellular operators to support rich multimedia services. However, reusing cellular resources for both D2D and cellular communication introduces interference issues. In such systems, interference management is of utmost importance because improper interference coordination may lead to a self-destructive network. Power control and beamforming appears to be viable techniques for interference management which can also be used to enhance the energy efficiency of the system. Network coordinated sum power optimization schemes for D2D communications underlaying uplink and downlink cellular spectrum is considered in this thesis. In particular, the system optimization target is to minimize the sum transmission power while guaranteeing the user specific rate constraints. Novel algorithms are proposed to solve the power minimization problem optimally. For the uplink, the problem is solved using joint transmit power control and receive beamforming algorithm. The downlink problem is reformulated as a second-order cone program (SOCP), and thus, it can be solved efficiently via standard SOCP solvers. Moreover, a decentralized algorithm is proposed that reduces the amount of control information exchange in comparison to the centralized approach. The performance of the proposed algorithms is compared with the conventional cellular scheme. Simulation results demonstrate that the proposed underlay D2D communication approach is capable of achieving significant performance gains over the conventional cellular scheme. Results also illustrate that the power consumption of the system is highly affected by the location of the interfering cellular user and whether the resources are shared in uplink or downlink. Therefore, four different resource sharing areas are defined for D2D communications. These areas specify the type of resources (i.e., downlink and uplink) suitable for D2D communication.

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Hasan, Monowar. "Radio Resource Management for Relay-Aided Device-to-Device Communication." IEEE, 2013. http://hdl.handle.net/1993/30531.

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In this thesis, performance of relay-assisted Device-to-device (D2D) communication is investigated where D2D traffic is carried through relay nodes. I develop resource management schemes to maximize end-to-end rate as well as conversing rate requirements for cellular and D2D UEs under total power constraint. I also develop a low-complexity distributed solution using the concept of message passing. Considering the uncertainties in wireless links (e.g., when interference from other relay nodes and the link gains are not exactly known), I extend the formulation using robust resource allocation techniques. In addition, a distributed solution approach using stable matching is developed to allocate radio resources in an efficient and computationally inexpensive way under the bounded channel uncertainties. Numerical results show that, there is a distance threshold beyond which relay-assisted D2D communication significantly improves network performance at the cost of small increase in end-to-end delay when compared to conventional approach.

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Idris, Fakrulradzi. "Resource allocation for energy efficient device-to-device communications." Thesis, University of Manchester, 2019. https://www.research.manchester.ac.uk/portal/en/theses/resource-allocation-for-energy-efficient-devicetodevice-communications(fe38ee57-5947-497e-a744-373937f7f9ab).html.

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Device-to-Device (D2D) communication is one of the technologies for next generation communication system. Unlike traditional cellular network, D2D allows proximity users to communicate directly with each other without routing the data through a base station. The main aim of this study is to improve the overall energy efficiency (EE) of D2D communications overlaying cellular system. To reduce the complexity of joint EE optimization, we decompose the main EE problem into two subproblems; resource efficiency (RE) optimization in the first stage and EE optimization for D2D pairs in the second stage. Firstly, we propose an alternative two-stage RE-EE scheme for a single cellular user equipment (CUE) and a D2D pair utilizing uplink spectrum. Later, we extend this work for multiple CUEs and D2D pairs by considering the downlink orthogonal frequency division multiple access (OFDMA). By exploiting a range of optimization tools including the Bisection method, interior point algorithm, fractional programming, Dinkelbach approach, Lagrange dual decomposition, difference of convex functions, and concave-convex procedure, the original non-convex problems are solved and we present iterative two-stage RE-EE solutions. Simulation results demonstrate that the proposed two-stage scheme for uplink scenario outperforms the cellular mode and dedicated mode of communications and the performance is close to the global optimal solution. The results also show that the proposed schemes for downlink resource sharing provide improved system EE performance with significant gain on EE for D2D users compared to a two-stage EE-EE solution, which is obtained numerically. Furthermore, the RE and EE optimization for non-orthogonal multiple access (NOMA) are considered to study the effect of users' access to the whole spectrum. The results indicate that the proposed RE scheme for NOMA with D2D communications achieves higher system EE compared to the OFDMA based schemes.

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TRAN, ANH KHOA. "Resource Management for D2D Communications in Future Cellular Systems." Doctoral thesis, Università di Siena, 2017. http://hdl.handle.net/11365/1013216.

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Recently, with the increasing demand for local traffic, and the steep growth in mobile data traffic has gained a lot of attention. With current infrastructure deployments and radio resources, operators will not be able to cope with the upcoming demands. Consequently, discussions of the next generation of mobile networks, referred to as the fifth generation (5G), have started in both academia and industry. In addition to more capacity, stringent requirements for improving capacity, decreasing outage probability, low delays, low power consumptions and increasing reliability have been envisioned in 5G. Many solutions have been put forward, one of them being Device-to-Device (D2D) communications where Cellular User Equipments (CUEs) can transmit directly to one another bypassing the base station (BS) via uplink (UL) or downlink (DL) paths. In this dissertation, firstly we survey the background of D2D technologies, and a brief comparison of several popular D2D technologies and how they are integrated in cellular networks, possible requirements and challenges of D2D-enabled LTE-A networks. Then, we review the background of LTE-A physical and MAC layer and details of D2D communication in LTE-A. Secondly, we present the architecture of the multi-cell network scenario adopting frequency reuse across different cells, where Inter-Cell Interference (ICC) and Intra-Cell Interference (IACC) are consider, and present the mathematical formulation for SINR, capacity of both CUEs and D2D pairs in underlay and cellular mode. By exploiting frequency reuse, this research work aims to design wireless system level algorithms to utilize the spectrum resources efficiently in the next generation wireless heterogeneous network, where resource allocation and interference management algorithms to significantly improve user experience, system capacity, and avoidance outage probability for D2D communications underlaying wireless heterogeneous networks. A resource allocation for the D2D communications underlaying cellular network is given in this dissertation, which is applied the basic of Round Robin (RR) and Proportional Fair (PF) scheduling, and we also provided some techniques to improve the cell capacity while controlling outage probability in the presence of D2D communications (underlay mode) as RR-FAR, RR-FAR-OUT, PF2 and PF2-OUT, after that we propose a CUE and D2D capacity and outage probability analyze models of both underlay and cellular mode. Finally, the performance of D2D communication underlaying LTE-A system are investigate in a single-cell and multi-cells scenarios via system-level simulation with different settings and compared with other scheduler techniques and cellular mode (CELLM). The simulation results show that considerable performance capacities are achieved by enabling direct D2D data paths to replace conventional uplink (UL) and downlink (DL) data paths for local data traffic between proximate devices, and by allowing non-orthogonal resource reuse between D2D and cellular uplink transmission. The initial tests demonstrate that the proposed scheduling method successfully improves the capacity and mitigates interferences resulting from co-channel interference exists between a CUE and D2D pairs of the cell.

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Shaikh, Farrukh Salim [Verfasser], and Roland [Gutachter] Wismüller. "Routing for multi-hop device-to-device (D2D) networks / Farrukh Salim Shaikh ; Gutachter: Roland Wismüller." Siegen : Universitätsbibliothek der Universität Siegen, 2021. http://d-nb.info/1235224104/34.

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Zhao, Jingjing. "Resource allocation for D2D communications based on matching theory." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/25990.

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Device-to-device (D2D) communications underlaying a cellular infrastructure takes advantage of the physical proximity of communicating devices and increasing resource utilisation. However, adopting D2D communications in complex scenarios poses substantial challenges for the resource allocation design. Meanwhile, matching theory has emerged as a promising framework for wireless resource allocation which can overcome some limitations of game theory and optimisation. This thesis focuses on the resource allocation optimisation for D2D communications based on matching theory. First, resource allocation policy is designed for D2D communications underlaying cellular networks. A novel spectrum allocation algorithm based on many-to-many matching is proposed to improve system sum rate. Additionally, considering the quality-of-service (QoS) requirements and priorities of di erent applications, a context-aware resource allocation algorithm based on many-to-one matching is proposed, which is capable of providing remarkable performance enhancement in terms of improved data rate, decreased packet error rate (PER) and reduced delay. Second, to improve resource utilisation, joint subchannel and power allocation problem for D2D communications with non-orthogonal multiple access (NOMA) is studied. For the subchannel allocation, a novel algorithm based on the many-to-one matching is proposed for obtaining a suboptimal solution. Since the power allocation problem is non-convex, sequential convex programming is adopted to transform the original power allocation problem to a convex one. The proposed algorithm is shown to enhance the network sum rate and number of accessed users. Third, driven by the trend of heterogeneity of cells, the resource allocation problem for NOMA-enhanced D2D communications in heterogeneous networks (HetNets) is investigated. In such a scenario, the proposed resource allocation algorithm is able to closely approach the optimal solution within a limited number of iterations and achieves higher sum rate compared to traditional HetNets schemes. Thorough theoretical analysis is conducted in the development of all proposed algorithms, and performance of proposed algorithm is evaluated via comprehensive simulations. This thesis concludes that matching theory based resource allocation for D2D communications achieves near-optimal performance with acceptable complexity. In addition, the application of D2D communications in NOMA and HetNets can improve system performance in terms of sum rate and users connectivity.

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Guo, Jianding. "Theoretical research on graph coloring : Application to resource allocation in device-to-device 4G radio system (LTE)." Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCA007/document.

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Le problème de coloration de graphe est un problème NP-complet particulièrement étudié, qui permet de modéliser de problèmes dans des domaines variés. Dans cette thèse, de nouveaux algorithmes exacts basés sur une étude de la structure du graphe sont proposés. Ce travail s'appuie sur l'algorithme « Total solutions Exact graph Coloring » (TexaCol) qui construit toutes les solutions en exploitant l'ensemble des cliques d'un graphe. Deux algorithmes exacts, « Partial best solutions Exact graph Coloring » (PexaCol) et « All best solutions Exact graph Coloring » (AexaCol), sont présentés ici pour construire certaines solutions optimales ou toutes les meilleures solutions. Ces deux algorithmes utilisent la méthode de backtracking, dans laquelle ils ne choisissent que les sous-ensembles de meilleurs solutions pour continuer la coloration. L’analyse de résultat montre que PexaCol et AexaCol sont capables de traiter des graphes plus grands que TexaCol. Mais surtout, AexaCol trouve toutes les meilleures solutions significativement plus vite que TexaCol ainsi que le solveur Gurobi, qui sont utilisés comme référence.La téléphonie mobile est un domaine en plein essor qui peut s'appuyer sur une modélisation à base de graphes. Actuellement, les techniques de type « Device-to-Device » (D2D) prennent une place importante dans les réseaux mobiles. L’allocation de ressource constitue l'un des principaux problèmes en matière de performance. Pour assigner efficacement une ressource radio à une paire D2D dans le système Long-Term Evolution (LTE), un schéma systématique d'allocation de ressources est proposé dans cette thèse. Il est basé sur une clusturisation des liens D2D, et permet de prendre en compte à la fois l'allocation inter-cluster et intra-cluster des ressources. En déterminant les zones d'interférence, le problème d'allocation des ressources inter-cluster est formulé comme un problème de coloration de graphe dynamique. Un algorithme de coloration de graphe dynamique est ainsi proposé, basé sur PexaCol. Cet algorithme peut assigner les ressources radio aux clusters qui sont générés ou supprimés dynamiquement. L’analyse numérique montre que cet algorithme assure une bonne performance en termes d'utilisation des ressources, de temps d’exécution et d'adaptabilité. Concernant le problème d’allocation de ressources inter-cluster, une méthode fondée sur la topologie est proposée, intégrant naturellement l'allocation de puissance et l’allocation de Resource Block (RB). Pour simplifier ce problème d'allocation de ressources, la meilleure topologie est choisie à chaque étape, celle qui permet d'obtenir le meilleur débit en utilisant le moins de RBs. A partir de ce procédé, quatre algorithmes d'optimisation sont proposés: l’algorithme glouton statique, PexaCol statique, PexaCol dynamique et PexaCol dynamique approximatif. L'analyse des résultats montre que pour les petits clusters, les versions statiques et dynamiques de PexaCol permettent d'obtenir un index d’optimisation maximal en choisissant la meilleure topologie locale pour chaque noeud. A l'opposé, les algorithmes "glouton statique" et "PexaCol dynamique approximatif" permettent d'obtenir une solution sous-optimale pour l'optimisation locale avec une complexité moindre. Pour les grands clusters, avec certaine séquence de la coloration, le PexaCol dynamique approximatif est mieux que l’algorithme glouton statique pour l’index d’optimisation pendant un temps d’exécution acceptable
Graph coloring problem is a famous NP-complete problem, which has extensive applications. In the thesis, new exact graph coloring algorithms are researched from a graph structure point of view. Based on Total solutions Exact graph Coloring algorithm (TexaCol) which is capable of getting all coloring solution subsets for each subgraph, two other exact algorithms, Partial best solutions Exact graph Coloring algorithm (PexaCol) and All best solutions Exact graph Coloring algorithm (AexaCol), are presented to get multiple best solutions. These two algorithms utilize the backtracking method, in which they only choose the best solution subset each step to continue the coloring until partial or all best solutions are obtained. The result analysis shows that PexaCol and AexaCol can deal with larger graphs than TexaCol and especially, AexaCol runs much faster than TexaCol and the solver Gurobi to get all best solutions.Device-to-Device (D2D) is a promising technique for the future mobile networks, such as 5th generation wireless systems (5G), and the resource allocation is one of the most crucial problems for its performance. In order to efficiently allocate radio resource for D2D links in Long-Term Evolution (LTE) system, a systematic resource allocation scheme is proposed based on D2D clusters, including the inter-cluster resource allocation and the intra-cluster resource allocation. With the cluster interference range, the inter-cluster resource allocation problem is formulated as a dynamic graph coloring problem, and a dynamic graph coloring algorithm is designed based on PexaCol. This algorithm is able to allocate radio resource to clusters while they are dynamically generated and deleted. The numerical analysis results show that this algorithm has good performance in resource utilization, runtime and scalability.For the intra-cluster resource allocation problem, a topology-based resource allocation method is designed naturally combining power allocation with Resource Block (RB) allocation. To simplify this associated optimization problem, a local optimal method is proposed, in which the best topology is chosen each step achieving the maximal throughput with the minimum number of assigned RBs. With respect to this method, four algorithms are presented: static greedy, static PexaCol, dynamic PexaCol and dynamic PexaCol approximate. Result analysis shows that for small-scale clusters, static PexaCol and dynamic PexaCol are capable of getting a maximal optimization index by locally choosing the best topology for each node while static greedy and dynamic PexaCol approximate are able to get the suboptimal solution for the local optimization with much lower complexity. For large-scale clusters, giving certain treating sequences, the dynamic PexaCol approximate performs better than static greedy regarding the optimization index within an acceptable runtime

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Toukabri, Thouraya. "CVS : a framework architecture for D2D-based cellular vehicular services in 4G networks and beyond." Thesis, Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0004/document.

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L'explosion du trafic dans les réseaux mobiles d'aujourd'hui est l'une des préoccupations majeures des opérateurs mobiles. En effet, entre investir dans le développement de l’infrastructure pour supporter l’évolution des besoins des utilisateurs et faire face à la concurrence accrue des nouveaux acteurs du marché, l’enjeu est considérable. Dans ce contexte, les communications Device-to-Device (D2D) offrent aux opérateurs mobiles de nouvelles opportunités aussi bien financières que techniques, à travers les communications directes entre les appareils mobiles permettant de délester le réseau d'une partie du trafic. L'organisme de standardisation 3GPP a défini des évolutions de son architecture LTE/4G fonctionnelle pour supporter les communications D2D dans le cadre de Services de Proximité (ProSe). Cependant, les modèles économiques autour de ces nouveaux services sont encore flous et les solutions actuellement proposées par le 3GPP visent un déploiement à court terme d’un ensemble limité de services (ex : les services de sécurité publique). La première contribution proposée dans le cadre de cette thèse est une évolution de l'architecture ProSe vers une architecture cible distribuée dans laquelle les fonctions liées à ProSe sont mutualisées avec d'autres fonctions réseaux. La deuxième contribution porte sur l’intégration des services véhiculaires dans les réseaux mobiles en tant que services ProSe particuliers reposant sur les communications D2D. L'architecture CVS (Cellular Vehicular Services) est alors proposée comme solution pour un déploiement à grande échelle des services véhiculaires en s'appuyant sur une nouvelle évolution de l’architecture ProSe distribuée. Un algorithme de « clustering » ainsi que des procédures de communication en mode relais D2D sont utilisés dans la conception de la solution afin d’optimiser l'usage des ressources du réseau. Enfin, les performances de ces contributions sont évaluées à l'aide de modèles analytiques et de simulations afin de valider les approches et solutions proposées
The traffic explosion in today’s mobile networks is one of the major concerns of mobile operators. This explosion is mostly widening the gap between networks’ capacities and users’ growing needs in terms of bandwidth and QoS (Quality of Service), which directly impacts operators’ business profitability. In this context, Device-to-Device (D2D) communications offer mobile operators business and technical opportunities by allowing the network traffic offload with D2D direct communications between mobile devices. The recent standardization of D2D-based services as Proximity Services (ProSe) by the 3GPP provides already a set of enhancements to the current LTE/4G architecture to support these services. However, still in its infancy, the proposed solutions are envisioned for short-term market deployments and for a limited set of service categories (i.e public safety services). As a first contribution of this thesis, the proposed Distributed ProSe Architecture enhances the current ProSe architecture for a longer term deployment perspective of D2D-based services. On the basis of this enhanced architecture, vehicular communications and related services are further investigated as a specific implementation of ProSe as well as a new market opportunity for mobile operators. The CVS (Cellular Vehicular Services) solution is then introduced as an architecture framework that enables the integration of vehicular networks into mobile operators’ network infrastructure. A mobile network clustering algorithm and D2D relay-based communication mechanisms are used in the solution design in order to optimize the use of both core and radio network resources. Performance evaluation through analytical modeling and simulations are also carried out to validate the proposed contributions

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George, Geordie. "Device-to-device communication and wearable networks harnessing spatial proximity." Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/404986.

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Spatially proximal devices wanting to exchange information are expected to become more prevalent in wireless networks, rendering the option for direct device-to-device (D2D) communication increasingly important. On the one hand, within networks where communication via infrastructure has been the convention, enabling such an option for short-range and single-hop communication between co-located devices might potentially bring about performance benefits on several accounts. On the other hand, in the realm of networks where direct interaction between devices has been an obvious option, there is a growing demand for supporting extreme-data-rate applications and much denser deployments of simultaneous transmissions. This dissertation explores these aspects by addressing two main problems: (i) analyzing the performance benefits of D2D communication integrated into cellular mobile networks, and (ii) investigating the feasibility of mmWave (millimeter wave) frequencies for personal networks of wearable (body-born) devices in enclosed settings. Under sufficient spatial locality in wireless traffic within cellular networks, the D2D mode of communication can be leveraged to employ a denser spectral reuse, thereby achieving very high area spectral efficiencies (bits/s/Hz per unit area). Enabling D2D entails a reshaping of the network topology comprising the sources of useful signal and harmful interference from the vantage of each receiver, which is a factor that delimits network performance fundamentally. Therefore, to gauge the performance gains of D2D and to identify the challenges thereof, it is essential to model D2D communication in a large multicellular setting, without missing key features of the ensuing interference environment. In this regard, we develop a robust analytical framework, utilizing tools from stochastic geometry. The dissertation propounds a novel approach to the application of stochastic geometry that is shown to improve the simplicity, accuracy, and generality of wireless network analysis. The performance evaluation conducted using the framework, while demonstrating the potential of D2D, also indicates the need for managing the interference surge. Prompted by this, and to illustrate the flexibility of the framework, we further extended it to incorporate interference protection schemes based on exclusion regions and the benefits thereof are assessed. The presence of multiple wearable networks—each comprising several on-body device-pairs worn by people—in proximity might result in an extreme density of simultaneous wireless transmissions. Such a scenario is expected to become commonplace in enclosed settings, e.g., commuter trains, subways, airplanes, airports or offices, and be further challenging due to an increasing demand for data-rate-intensive wireless applications in wearable technology. This combination of very-short-range communication, high-data-rate applications, and dense spectral reuse seems to render operation at mmWave frequencies a suitable candidate; add to that the possibility of accommodating antenna arrays within devices for directional beamforming. Hence, we investigate the feasibility of enclosed mmWave wearable networks, with a particular focus on appropriately modeling the impact of propagation mechanisms at these frequencies. In the propagation modeling, specular reflections off surfaces are explicitly accounted for, as they are expected to contribute useful signal power while, at the same time, intensify the interference. Recognizing the increased prominence of blocking by obstacles, body-blockages in the direct and reflected propagation paths are also modeled. The impact of these mechanisms on the spectral efficiency of the network is evaluated, aided by the application of stochastic geometry and random shape theory. Under relevant indoor settings, and in the plausible absence of strong direct signal, the reliability of surface reflections in providing useful signal power for efficient communication is investigated and the need for directional antennas is established.
Se espera que los dispositivos espacialmente proximales que desean intercambiar información se vuelvan más frecuentes en redes inalámbricas, lo que hace cada vez más importante la opción para la comunicación directa de dispositivo-a-dispositivo (D2D). Por un lado, dentro de las redes en las que la comunicación a través de la infraestructura ha sido la convención, permitir tal opción para la comunicación de corto alcance y single-hop entre dispositivos ubicados conjuntamente podría potencialmente generar beneficios de rendimiento en varios aspectos. Por otro lado, en el ámbito de las redes en las que la interacción directa entre dispositivos ha sido una opción obvia, existe una demanda creciente de soportar aplicaciones de velocidad extrema de datos e implementaciones mucho más densas de transmisiones simultáneas. Esta disertación explora dichos aspectos abordando dos problemas principales: (i) analizando los beneficios de rendimiento de la comunicación D2D integrada en las redes móviles celulares y (ii) investigando la viabilidad de las frecuencias mmWave (onda milimétrica) para redes personales de dispositivos wearables (usado en el cuerpo) en entornos cerrados. Bajo suficiente localidad espacial en el tráfico inalámbrico en redes celulares, el modo de comunicación D2D puede ser apalancado para emplear una reutilización espectral más densa, logrando así eficiencias espectrales de área muy alta (bits/s/Hz por unidad de área). La habilitación de D2D implica una remodelación de la topología de red que comprende las fuentes de señal útil e interferencia perjudicial desde la ventaja de cada receptor, lo cual es un factor que delimita el funcionamiento de la red de manera fundamental. Por tanto, para medir las ganancias de rendimiento de D2D y para identificar los retos de la misma, es esencial para modelar la comunicación D2D en un gran ajuste multicelular, sin faltar las características clave del entorno de interferencia resultante. En este sentido, se desarrolla un sólido marco analítico, utilizando herramientas de geometría estocástica. La disertación propone un nuevo enfoque para la aplicación de la geometría estocástica para mejorar la simplicidad, precisión y generalidad del análisis de redes inalámbricas. La evaluación realizada utilizando dicho enfoque, al mismo tiempo que demuestra el potencial de D2D, también indica la necesidad de manejar la oleada de interferencia. Impulsado por estos resultados, y para ilustrar la flexibilidad del marco, también se amplía para incorporar esquemas de protección contra interferencias basados en regiones de exclusión y se evalúan sus los beneficios. La presencia de redes wearables múltiples—cada una de las cuales comprende varios pares de dispositivos en el cuerpo desgastados por personas—en proximidad puede dar como resultado una densidad extrema de transmisiones inalámbricas simultáneas. Se espera que este escenario se convierta habitual en entornos cerrados, por ejemplo, trenes de cercanías, subterráneos, aviones, aeropuertos u oficinas, y será un reto adicional debido a la creciente demanda de aplicaciones inalámbricas intensivas en datos en tecnología wearable. Esta combinación de comunicaciones de muy corto alcance, en aplicaciones de alta velocidad de datos y de reutilización espectral densa parece hacer que la operación en las frecuencias mmWave sea un candidato adecuado; se añade la posibilidad de alojar conjuntos de antenas dentro de dispositivos para el beamforming direccionales. Por tanto, también se investiga la viabilidad de las redes wearables mmWave cerradas, con especial énfasis en modelar apropiadamente el impacto de los mecanismos de propagación en estas frecuencias. En el modelado de propagación, las reflexiones especulares de las superficies se explican explícitamente, ya que se espera que contribuyan a la potencia de la señal útil, mientras que, al mismo tiempo, intensificar la interferencia. Reconociendo la mayor prominencia del bloqueo por obstáculos, también se modelan los bloqueos corporales en los caminos de propagación directa y reflejada. El impacto de estos mecanismos en la eficiencia espectral de la red se evalúa, ayudado por la aplicación de la geometría estocástica y la teoría de la forma aleatoria. Bajo configuraciones internas relevantes, y en la ausencia plausible de señal directa fuerte, se investiga la fiabilidad de las reflexiones superficiales proporcionando potencia de señal útil para una comunicación eficiente y se establece la necesidad de antenas direccionales.

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14

Ibrahim, Rita. "Utilisation des communications Device-to-Device pour améliorer l'efficacité des réseaux cellulaires." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC002/document.

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Cette thèse étudie les communications directes entre les mobiles, appelées communications D2D, en tant que technique prometteuse pour améliorer les futurs réseaux cellulaires. Cette technologie permet une communication directe entre deux terminaux mobiles sans passer par la station de base. La modélisation, l'évaluation et l'optimisation des différents aspects des communications D2D constituent les objectifs fondamentaux de cette thèse et sont réalisés principalement à l'aide des outils mathématiques suivants: la théorie des files d'attente, l'optimisation de Lyapunov et les processus de décision markovien partiellement observable POMDP. Les résultats de cette étude sont présentés en trois parties. Dans la première partie, nous étudions un schéma de sélection entre mode cellulaire et mode D2D. Nous dérivons les régions de stabilité des scénarios suivants: réseaux cellulaires purs et réseaux cellulaires où les communications D2D sont activées. Une comparaison entre ces deux scénarios conduit à l'élaboration d'un algorithme de sélection entre le mode cellulaire et le mode D2D qui permet d'améliorer la capacité du réseau. Dans la deuxième partie, nous développons un algorithme d'allocation de ressources des communications D2D. Les utilisateurs D2D sont en mesure d'estimer leur propre qualité de canal, cependant la station de base a besoin de recevoir des messages de signalisation pour acquérir cette information. Sur la base de cette connaissance disponibles au niveau des utilisateurs D2D, une approche d'allocation des ressources est proposée afin d'améliorer l'efficacité énergétique des communications D2D. La version distribuée de cet algorithme s'avère plus performante que celle centralisée. Dans le schéma distribué des collisions peuvent se produire durant la transmission de l'état des canaux D2D ; ainsi un algorithme de réduction des collisions est élaboré. En outre, la mise en œuvre des algorithmes centralisé et distribué dans un réseau cellulaire, type LTE, est décrite en détails. Dans la troisième partie, nous étudions une politique de sélection des relais D2D mobiles. La mobilité des relais représente un des principaux défis que rencontre toute stratégie de sélection de relais. Le problème est modélisé par un processus contraint de décision markovien partiellement observable qui prend en compte le dynamisme des relais et vise à trouver la politique de sélection de relais qui optimise la performance du réseau cellulaire sous des contraintes de coût
This thesis considers Device-to-Device (D2D) communications as a promising technique for enhancing future cellular networks. Modeling, evaluating and optimizing D2D features are the fundamental goals of this thesis and are mainly achieved using the following mathematical tools: queuing theory, Lyapunov optimization and Partially Observed Markov Decision Process (POMDP). The findings of this study are presented in three parts. In the first part, we investigate a D2D mode selection scheme. We derive the queuing stability regions of both scenarios: pure cellular networks and D2D-enabled cellular networks. Comparing both scenarios leads us to elaborate a D2D vs cellular mode selection design that improves the capacity of the network. In the second part, we develop a D2D resource allocation algorithm. We observe that D2D users are able to estimate their local Channel State Information (CSI), however the base station needs some signaling exchange to acquire this information. Based on the D2D users' knowledge of their local CSI, we provide an energy efficient resource allocation framework that shows how distributed scheduling outperforms centralized one. In the distributed approach, collisions may occur between the different CSI reporting; thus, we propose a collision reduction algorithm. Moreover, we give a detailed description on how both centralized and distributed algorithms can be implemented in practice. In the third part, we propose a mobile relay selection policy in a D2D relay-aided network. Relays' mobility appears as a crucial challenge for defining the strategy of selecting the optimal D2D relays. The problem is formulated as a constrained POMDP which captures the dynamism of the relays and aims to find the optimal relay selection policy that maximizes the performance of the network under cost constraints

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15

Rebecchi, Filippo. "Délestage de données en D2D : de la modélisation à la mise en oeuvre." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066234/document.

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Le trafic mobile global atteindra 24,3 exa-octets en 2019. Accueillir cette croissance dans les réseaux d’accès radio devient un véritable casse-tête. Nous porterons donc toute notre attention sur l'une des solutions à ce problème : le délestage (offloading) grâce à des communications de dispositif à dispositif (D2D). Notre première contribution est DROiD, une stratégie qui exploite la disponibilité de l'infrastructure cellulaire comme un canal de retour afin de suivre l'évolution de la diffusion d’un contenu. DROiD s’adapte au rythme de la diffusion, permettant d'économiser une quantité élevée de données cellulaires, même dans le cas de contraintes de réception très serrées. Ensuite, nous mettons l'accent sur les gains que les communications D2D pourraient apporter si elles étaient couplées avec les transmissions multicast. Par l’utilisation équilibrée d'un mix de multicast, et de communications D2D, nous pouvons améliorer, à la fois, l'efficacité spectrale ainsi que la charge du réseau. Afin de permettre l’adaptation aux conditions réelles, nous élaborons une stratégie d'apprentissage basée sur l'algorithme dit ‘’bandit manchot’’ pour identifier la meilleure combinaison de communications multicast et D2D. Enfin, nous mettrons en avant des modèles de coûts pour les opérateurs, désireux de récompenser les utilisateurs qui coopèrent dans le délestage D2D. Nous proposons, pour cela, de séparer la notion de seeders (utilisateurs qui transportent contenu, mais ne le distribuent pas) et de forwarders (utilisateurs qui sont chargés de distribuer le contenu). Avec l'aide d’un outil analytique basée sur le principe maximal de Pontryagin, nous développons une stratégie optimale de délestage
Mobile data traffic is expected to reach 24.3 exabytes by 2019. Accommodating this growth in a traditional way would require major investments in the radio access network. In this thesis, we turn our attention to an unconventional solution: mobile data offloading through device-to-device (D2D) communications. Our first contribution is DROiD, an offloading strategy that exploits the availability of the cellular infrastructure as a feedback channel. DROiD adapts the injection strategy to the pace of the dissemination, resulting at the same time reactive and relatively simple, allowing to save a relevant amount of data traffic even in the case of tight delivery delay constraints.Then, we shift the focus to the gains that D2D communications could bring if coupled with multicast wireless networks. We demonstrate that by employing a wise balance of multicast and D2D communications we can improve both the spectral efficiency and the load in cellular networks. In order to let the network adapt to current conditions, we devise a learning strategy based on the multi-armed bandit algorithm to identify the best mix of multicast and D2D communications. Finally, we investigate the cost models for operators wanting to reward users who cooperate in D2D offloading. We propose separating the notion of seeders (users that carry content but do not distribute it) and forwarders (users that are tasked to distribute content). With the aid of the analytic framework based on Pontryagin's Maximum Principle, we develop an optimal offloading strategy. Results provide us with an insight on the interactions between seeders, forwarders, and the evolution of data dissemination

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16

Ashraf, M. I. (Muhammad Ikram). "Radio resource management in device-to-device and vehicle-to-vehicle communication in 5G networks and beyond." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526224626.

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Abstract Future cellular networks need to support the ever-increasing demand of bandwidth-intensive applications and interconnection of people, devices, and vehicles. Small cell network (SCN)-based communication together with proximity- and social-aware connectivity is conceived as a vital component of these networks to enhancing spectral efficiency, system capacity, and quality-of-experience (QoE). To cope with diverse application needs for the heterogeneous ecosystem, radio resource management (RRM) is one of the key research areas for the fifth-generation (5G) network. The key goals of this thesis are to develop novel, self-organizing, and low-complexity resource management algorithms for emerging device-to-device (D2D) and vehicle-to-vehicle (V2V) wireless systems while explicitly modeling and factoring network contextual information to satisfy the increasingly stringent requirements. Towards achieving this goal, this dissertation makes a number of key contributions. First, the thesis focuses on interference management techniques for D2D-enabled macro network and D2D-enabled SCNs in the downlink, while leveraging users’ social-ties, dynamic clustering, and user association mechanisms for network capacity maximization. A flexible social-aware user association technique is proposed to maximize network capacity. The second contribution focuses on ultra-reliable low-latency communication (URLLC) in vehicular networks in which interference management and resource allocation techniques are investigated, taking into account traffic and network dynamics. A joint power control and resource allocation mechanism is proposed to minimize the total transmission power while satisfying URLLC constraints. To overcome these challenges, novel algorithms are developed by combining several methodologies from graph theory, matching theory and Lyapunov optimization. Extensive simulations validate the performance of the proposed approaches, outperforming state-of-the-art solutions. Notably, the results yield significant performance gains in terms of capacity, delay reductions, and improved reliability as compared with conventional approaches
Tiivistelmä Tulevaisuuden solukkoverkkojen pitää pystyä tukemaan yhä suurempaa kaistanleveyttä vaativia sovelluksia sekä yhteyksiä ihmisten, laitteiden ja ajoneuvojen välillä. Piensoluverkkoihin (SCN) pohjautuvaa tietoliikennettä yhdistettynä paikka- ja sosiaalisen tietoisuuden huomioiviin verkkoratkaisuihin pidetään yhtenä elintärkeänä osana tulevaisuuden solukkoverkkoja, joilla pyritään tehostamaan spektrinkäytön tehokkuutta, järjestelmän kapasiteettia sekä kokemuksen laatua (QoE). Radioresurssien hallinta (RRM) on eräs keskeisistä viidennen sukupolven (5G) verkkoihin liittyvistä tutkimusalueista, joilla pyritään hallitsemaan heterogeenisen ekosysteemin vaihtelevia sovellustarpeita. Tämän väitöstyön keskeisinä tavoitteina on kehittää uudenlaisia itseorganisoituvia ja vähäisen kompleksisuuden resurssienhallinta-algoritmeja laitteesta-laitteeseen (D2D) ja ajoneuvosta-ajoneuvoon (V2V) toimiville uusille langattomille järjestelmille, sekä samalla mallintaa ja tuottaa verkon kontekstikohtaista tietoa vastaamaan koko ajan tiukentuviin vaatimuksiin. Tämä väitöskirja edistää näiden tavoitteiden saavuttamista usealla keskeisellä tuloksella. Aluksi väitöstyössä keskitytään häiriönhallinnan tekniikoihin D2D:tä tukevissa makroverkoissa ja laskevan siirtotien piensoluverkoissa. Käyttäjän sosiaalisia yhteyksiä, dynaamisia ryhmiä sekä osallistamismekanismeja hyödynnetään verkon kapasiteetin maksimointiin. Verkon kapasiteettia voidaan kasvattaa käyttämällä joustavaa sosiaaliseen tietoisuuteen perustuvaa osallistamista. Toinen merkittävä tulos keskittyy huippuluotettavaan lyhyen viiveen kommunikaatioon (URLLC) ajoneuvojen verkoissa, joissa tehtävää resurssien allokointia ja häiriönhallintaa tutkitaan liikenteen ja verkon dynamiikka huomioiden. Yhteistä tehonsäädön ja resurssien allokoinnin mekanismia ehdotetaan kokonaislähetystehon minimoimiseksi samalla, kun URLLC rajoitteita noudatetaan. Jotta esitettyihin haasteisiin voidaan vastata, väitöstyössä on kehitetty uudenlaisia algoritmeja yhdistämällä graafi- ja sovitusteorioiden sekä Lyapunovin optimoinnin menetelmiä. Laajat tietokonesimuloinnit vahvistavat ehdotettujen lähestymistapojen suorituskyvyn, joka on parempi kuin uusimmilla nykyisillä ratkaisuilla. Tulokset tuovat merkittäviä suorituskyvyn parannuksia erityisesti kapasiteetin lisäämisen, viiveiden vähentämisen ja parantuneen luotettavuuden suhteen verrattuna perinteisiin lähestymistapoihin

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17

Chen, Zheng. "Communication centrée sur les utilisateurs et les contenus dans les réseaux sans fil." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC092/document.

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Cette thèse porte sur plusieurs technologies de déchargement cellulaire pour les futurs réseaux sans fil avec l’amélioration envisagée sur la efficacité spatiale du spectre et l’efficacité énergétique. Notre recherche concerne deux directions principales, y compris la communication D2D underlaid dans les réseaux cellulaires et le caching proactif au bord de réseau.La première partie de cette thèse contient deux chapitres qui présentent nos résultats de recherche sur les réseaux cellulaire avec D2D underlaid. Notre recherche se focalise sur l’accès opportuniste distribué, dont la performance en termes du débit D2D est optimisé dans deux scénarios: 1) en supposant que l’utilisateur cellulaire avec un trafic saturé peut avoir une probabilité de couverture minimale; 2) en supposant que le trafic discontinu à l’utilisateur cellulaire, dont le délai moyen doit être maintenue au-dessous d’un certain seuil. La deuxième partie de cette thèse se focalise sur les méthodes de caching proactif au bord de réseau, y compris le caching aux petites cellules et aux appareils des utilisateurs. Tout d’abord, nous étudions le placement de contenu probabiliste dans différents types de réseaux et avec différents objectifs d’optimisation. Deuxièmement, pour le caching aux petites cellules, nous proposons un schéma coopérative parmi les petites stations de base, qui exploite le gain combiné du caching coopérative et les techniques de multipoint coordonnée. Les modèles de processus ponctuel nous permet de créer la connexion entre la diversité de transmission en couche PHY et la diversité de contenus stockés
This thesis focuses on several emerging technologies towards future wireless networks with envisaged improvement on the area spectral efficiency and energy efficiency. The related research involves two major directions, including deviceto- device (D2D) communication underlaid cellular networks and proactive caching at network edge. The first part of this thesis starts with introducing D2D underlaid cellular network model and distributed access control methods for D2D users that reuse licensed cellular uplink spectrum. We aim at optimize the throughput of D2D network in the following two scenarios: 1) assuming always backlogged cellular users with coverage probability constraint, 2) assuming bursty packet arrivals at the cellular user, whose average delay must be kept below a certain threshold. The second part of this thesis focuses on proactive caching methods at network edge, including at small base stations (SBSs) and user devices. First, we study and compare the performance of probabilistic content placement in different types of wireless caching networks and with different optimization objectives. Second, we propose a cooperative caching and transmission strategy in a cluster-centric small cell networks (SCNs), which exploits the combined gain of cache-level cooperation and CoMP technique. Using spatial models from stochastic geometry, we build the connection between PHY transmission diversity and the content diversity in local caches

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18

Rebecchi, Filippo. "Délestage de données en D2D : de la modélisation à la mise en oeuvre." Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066234.

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Abstract:

Le trafic mobile global atteindra 24,3 exa-octets en 2019. Accueillir cette croissance dans les réseaux d’accès radio devient un véritable casse-tête. Nous porterons donc toute notre attention sur l'une des solutions à ce problème : le délestage (offloading) grâce à des communications de dispositif à dispositif (D2D). Notre première contribution est DROiD, une stratégie qui exploite la disponibilité de l'infrastructure cellulaire comme un canal de retour afin de suivre l'évolution de la diffusion d’un contenu. DROiD s’adapte au rythme de la diffusion, permettant d'économiser une quantité élevée de données cellulaires, même dans le cas de contraintes de réception très serrées. Ensuite, nous mettons l'accent sur les gains que les communications D2D pourraient apporter si elles étaient couplées avec les transmissions multicast. Par l’utilisation équilibrée d'un mix de multicast, et de communications D2D, nous pouvons améliorer, à la fois, l'efficacité spectrale ainsi que la charge du réseau. Afin de permettre l’adaptation aux conditions réelles, nous élaborons une stratégie d'apprentissage basée sur l'algorithme dit ‘’bandit manchot’’ pour identifier la meilleure combinaison de communications multicast et D2D. Enfin, nous mettrons en avant des modèles de coûts pour les opérateurs, désireux de récompenser les utilisateurs qui coopèrent dans le délestage D2D. Nous proposons, pour cela, de séparer la notion de seeders (utilisateurs qui transportent contenu, mais ne le distribuent pas) et de forwarders (utilisateurs qui sont chargés de distribuer le contenu). Avec l'aide d’un outil analytique basée sur le principe maximal de Pontryagin, nous développons une stratégie optimale de délestage
Mobile data traffic is expected to reach 24.3 exabytes by 2019. Accommodating this growth in a traditional way would require major investments in the radio access network. In this thesis, we turn our attention to an unconventional solution: mobile data offloading through device-to-device (D2D) communications. Our first contribution is DROiD, an offloading strategy that exploits the availability of the cellular infrastructure as a feedback channel. DROiD adapts the injection strategy to the pace of the dissemination, resulting at the same time reactive and relatively simple, allowing to save a relevant amount of data traffic even in the case of tight delivery delay constraints.Then, we shift the focus to the gains that D2D communications could bring if coupled with multicast wireless networks. We demonstrate that by employing a wise balance of multicast and D2D communications we can improve both the spectral efficiency and the load in cellular networks. In order to let the network adapt to current conditions, we devise a learning strategy based on the multi-armed bandit algorithm to identify the best mix of multicast and D2D communications. Finally, we investigate the cost models for operators wanting to reward users who cooperate in D2D offloading. We propose separating the notion of seeders (users that carry content but do not distribute it) and forwarders (users that are tasked to distribute content). With the aid of the analytic framework based on Pontryagin's Maximum Principle, we develop an optimal offloading strategy. Results provide us with an insight on the interactions between seeders, forwarders, and the evolution of data dissemination

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19

Toukabri, Thouraya. "CVS : a framework architecture for D2D-based cellular vehicular services in 4G networks and beyond." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0004.

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L'explosion du trafic dans les réseaux mobiles d'aujourd'hui est l'une des préoccupations majeures des opérateurs mobiles. En effet, entre investir dans le développement de l’infrastructure pour supporter l’évolution des besoins des utilisateurs et faire face à la concurrence accrue des nouveaux acteurs du marché, l’enjeu est considérable. Dans ce contexte, les communications Device-to-Device (D2D) offrent aux opérateurs mobiles de nouvelles opportunités aussi bien financières que techniques, à travers les communications directes entre les appareils mobiles permettant de délester le réseau d'une partie du trafic. L'organisme de standardisation 3GPP a défini des évolutions de son architecture LTE/4G fonctionnelle pour supporter les communications D2D dans le cadre de Services de Proximité (ProSe). Cependant, les modèles économiques autour de ces nouveaux services sont encore flous et les solutions actuellement proposées par le 3GPP visent un déploiement à court terme d’un ensemble limité de services (ex : les services de sécurité publique). La première contribution proposée dans le cadre de cette thèse est une évolution de l'architecture ProSe vers une architecture cible distribuée dans laquelle les fonctions liées à ProSe sont mutualisées avec d'autres fonctions réseaux. La deuxième contribution porte sur l’intégration des services véhiculaires dans les réseaux mobiles en tant que services ProSe particuliers reposant sur les communications D2D. L'architecture CVS (Cellular Vehicular Services) est alors proposée comme solution pour un déploiement à grande échelle des services véhiculaires en s'appuyant sur une nouvelle évolution de l’architecture ProSe distribuée. Un algorithme de « clustering » ainsi que des procédures de communication en mode relais D2D sont utilisés dans la conception de la solution afin d’optimiser l'usage des ressources du réseau. Enfin, les performances de ces contributions sont évaluées à l'aide de modèles analytiques et de simulations afin de valider les approches et solutions proposées
The traffic explosion in today’s mobile networks is one of the major concerns of mobile operators. This explosion is mostly widening the gap between networks’ capacities and users’ growing needs in terms of bandwidth and QoS (Quality of Service), which directly impacts operators’ business profitability. In this context, Device-to-Device (D2D) communications offer mobile operators business and technical opportunities by allowing the network traffic offload with D2D direct communications between mobile devices. The recent standardization of D2D-based services as Proximity Services (ProSe) by the 3GPP provides already a set of enhancements to the current LTE/4G architecture to support these services. However, still in its infancy, the proposed solutions are envisioned for short-term market deployments and for a limited set of service categories (i.e public safety services). As a first contribution of this thesis, the proposed Distributed ProSe Architecture enhances the current ProSe architecture for a longer term deployment perspective of D2D-based services. On the basis of this enhanced architecture, vehicular communications and related services are further investigated as a specific implementation of ProSe as well as a new market opportunity for mobile operators. The CVS (Cellular Vehicular Services) solution is then introduced as an architecture framework that enables the integration of vehicular networks into mobile operators’ network infrastructure. A mobile network clustering algorithm and D2D relay-based communication mechanisms are used in the solution design in order to optimize the use of both core and radio network resources. Performance evaluation through analytical modeling and simulations are also carried out to validate the proposed contributions

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Melo, Yuri Victor Lima de. "Controle de potÃncia e estratÃgias de eficiÃncia energÃtica para comunicaÃÃes D2D subjacentes redes celulares." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14911.

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Ericsson Brasil
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Em um mundo onde as pessoas contam com smartphone, smartwatch, tablet e outros dispositivos para mantÃ-las conectadas onde quer que vÃo, t odos esperam que seus aplicativos sejam executados sem problemas, tais como cham adas abandonadas, download lento e vÃdeos com saltos. Neste contexto, comunicaÃÃo dispositivo-a-dispositivo ( do inglÃs, Device-to-Device (D2D)) constitui uma tecnologia promissora, pois Ã um tipo de comun icaÃÃo direta e utiliza baixa potÃncia entre dispositivos prÃximos, permitindo-se desv iar o trÃfego da rede mÃvel, aumentar a eficiÃncia espectral e de potÃncia. Do ponto de vista do assi nante, D2D significa usar aplicaÃÃo sem problemas e aumentar o tempo de vida da bateria do celular. No entanto, a fim de realizar os ganhos potenciais das comunic aÃÃes D2D, algumas questÃes-chave devem ser abordadas, pois as comunicaÃÃes D 2D podem aumentar a interferÃncia co-canal e comprometer a qualidade do enlace das comunicaÃÃes celulares. Esta dissertaÃÃo foca em tÃcnicas de Gerenciamento de Recur sos de RÃdio (do inglÃs, Radio Resource Management (RRM)) para mitigar a interferÃncia co -canal para comunicaÃÃes D2D que se baseiam na EvoluÃÃo de Longo Prazo (do inglÃs, Long Ter m Evolution (LTE)), visando a reduÃÃo da interferÃncia intra- e inter-celular e na melho ria da eficiÃncia energÃtica. Os principais esquemas de Controle de PotÃncia (do inglÃs, Pow er Control (PC)) (e.g. OLPC,CLPC e SDPC) e um esquema hÃbrido (CLSD) sÃo calibrados e utilizad os no cenÃrio macro ou micro multicelular, usando diferentes cargas e InformaÃÃo do Est ado do Canal (do inglÃs, Channel State Information (CSI)) perfeita ou imperfeita. AlÃm diss o, o impacto da inclinaÃÃo da antena ( downtilt ) Ã analisado, que Ã usada para ajustar o raio de cobertura de u ma Evolved Node B (eNB) e reduzir a interferÃncia co-canal, aumentando o iso lamento de cÃlulas. Os resultados numÃricos indicam que os regimes de controle d e potÃncia e inclinaÃÃo da antena, devidamente calibrados, podem fornecer ganhos p ara a comunicaÃÃo celular e D2D. Em outras palavras, a tecnologia D2D pode ser utilizada para aumentar ainda mais a eficiÃncia de espectro e a eficiÃncia energÃtica se algoritm os de RRM forem utilizados adequadamente
In a world where people count on their smartphone, smartwatch, tablet and other devices to keep them connected wherever they go, they expect its application to run without problems, such as dropped calls, slow download and choppy videos. In this context, Device-to-Device (D2D) communication represents a promising technology, because it is a direct and low-power communication between devices close, allowing to offload the data transport network, increase spectral and power efficiency. From the subscriber point of view, D2D means to use applications without problem and increase battery life. However, in order to realize the potential gains of D2D communications, some key issues must be tackled, because D2D communications may increase the co-channel interference and compromise the link quality of cellular communications. This masterâs thesis focuses on Radio Resource Management (RRM) techniques, especially Power Control (PC) schemes, to mitigate the co-channel interference for D2D communications underlaying a Long Term Evolution (LTE) network, aiming at the reduction of the intra- and inter- cell interference and at the improvement of energy efficiency. The main PC schemes (e.g. OLPC, CLPC and SDPC) and a hybrid scheme (CLSD) are calibrated and used in macro- or micro- multicell scenario, using different loads and imperfect Channel State Information (CSI). In addition, the impact of downtilt is analyzed, which is used to adjust the coverage radius of an Evolved Node B (eNB) and reduce co-channel interference by increasing cell isolation. The numerical results indicate that PC schemes and downtilt, duly calibrated, can provide gains to cellular and D2D communications. In other words, D2D technology can be used to further increase the spectral and energy efficiency if RRM algorithms are used suitably.

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21

Amate, Ahmed Mohammed. "Device-device communication and multihop transmission for future cellular networks." Thesis, University of Hertfordshire, 2015. http://hdl.handle.net/2299/16309.

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The next generation wireless networks i.e. 5G aim to provide multi-Gbps data traffic, in order to satisfy the increasing demand for high-definition video, among other high data rate services, as well as the exponential growth in mobile subscribers. To achieve this dramatic increase in data rates, current research is focused on improving the capacity of current 4G network standards, based on Long Term Evolution (LTE), before radical changes are exploited which could include acquiring additional/new spectrum. The LTE network has a reuse factor of one; hence neighbouring cells/sectors use the same spectrum, therefore making the cell edge users vulnerable to inter-cell interference. In addition, wireless transmission is commonly hindered by fading and pathloss. In this direction, this thesis focuses on improving the performance of cell edge users in LTE and LTE-Advanced (LTE-A) networks by initially implementing a new Coordinated Multi-Point (CoMP) algorithm to mitigate cell edge user interference. Subsequently Device-to-Device (D2D) communication is investigated as the enabling technology for maximising Resource Block (RB) utilisation in current 4G and emerging 5G networks. It is demonstrated that the application, as an extension to the above, of novel power control algorithms, to reduce the required D2D TX power, and multihop transmission for relaying D2D traffic, can further enhance network performance. To be able to develop the aforementioned technologies and evaluate the performance of new algorithms in emerging network scenarios, a beyond-the-state-of-the-art LTE system-level simulator (SLS) was implemented. The new simulator includes Multiple-Input Multiple-Output (MIMO) antenna functionalities, comprehensive channel models (such as Wireless World initiative New Radio II i.e. WINNER II) and adaptive modulation and coding schemes to accurately emulate the LTE and LTE-A network standards. Additionally, a novel interference modelling scheme using the 'wrap around' technique was proposed and implemented that maintained the topology of flat surfaced maps, allowing for use with cell planning tools while obtaining accurate and timely results in the SLS compared to the few existing platforms. For the proposed CoMP algorithm, the adaptive beamforming technique was employed to reduce interference on the cell edge UEs by applying Coordinated Scheduling (CoSH) between cooperating cells. Simulation results show up to 2-fold improvement in terms of throughput, and also shows SINR gain for the cell edge UEs in the cooperating cells. Furthermore, D2D communication underlaying the LTE network (and future generation of wireless networks) was investigated. The technology exploits the proximity of users in a network to achieve higher data rates with maximum RB utilisation (as the technology reuses the cellular RB simultaneously), while taking some load off the Evolved Node B (eNB) i.e. by direct communication between User Equipment (UE). Simulation results show that the proximity and transmission power of D2D transmission yields high performance gains for a D2D receiver, which was demonstrated to be better than that of cellular UEs with better channel conditions or in close proximity to the eNB in the network. The impact of interference from the simultaneous transmission however impedes the achievable data rates of cellular UEs in the network, especially at the cell edge. Thus, a power control algorithm was proposed to mitigate the impact of interference in the hybrid network (network consisting of both cellular and D2D UEs). It was implemented by setting a minimum SINR threshold so that the cellular UEs achieve a minimum performance, and equally a maximum SINR threshold to establish fairness for the D2D transmission as well. Simulation results show an increase in the cell edge throughput and notable improvement in the overall SINR distribution of UEs in the hybrid network. Additionally, multihop transmission for D2D UEs was investigated in the hybrid network: traditionally, the scheme is implemented to relay cellular traffic in a homogenous network. Contrary to most current studies where D2D UEs are employed to relay cellular traffic, the use of idle nodes to relay D2D traffic was implemented uniquely in this thesis. Simulation results show improvement in D2D receiver throughput with multihop transmission, which was significantly better than that of the same UEs performance with equivalent distance between the D2D pair when using single hop transmission.

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SANTOS, Marcos Graciano. "Mecanismos de Identificação de Proximidade e Alocação de Recursos para uma Comunicação D2D Energeticamente Eficiente em Redes LTE-A." Universidade Federal de Pernambuco, 2014. https://repositorio.ufpe.br/handle/123456789/11573.

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Submitted by Lucelia Lucena (lucelia.lucena@ufpe.br) on 2015-03-09T19:50:50Z No. of bitstreams: 2 DISSERTAÇÃO Marcos Graciano Santos.pdf: 3653832 bytes, checksum: 63b7958428e143779e52059edac458d4 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
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Atualmente, mais de 200 milhões de usuários utilizam as redes 3G/LTE (Long Term Evolution). Com este aumento crescente de usuários com acesso sem fio, muitas pesquisas se concentram no esforço de desenvolvimento de soluções que permitam atender às demandas de redes com alta disponibilidade e altas taxas de transmissão sem considerar, em geral, as limitações de bateria dos dispositivos. Como requisito do LTE Advanced (especificações para a Quarta Geração de comunicações móveis) incluem-se os Serviços de Proximidade, comunicação denominada de dispositivo a dispositivo (D2D, do inglês: device-to-device) para atender ao desenvolvimento de novas demandas de serviços, como jogos e vídeos on-line ou transferência de conteúdos, aplicações que, a cada dia, requerem maiores consumos de energia. Neste trabalho, realizamos medições que avaliam o consumo da comunicação dispositivo-estação base e propomos primeiramente um algoritmo de identificação de pares de dispositivos e definição de limiares de referência, diferentemente de outros trabalhos, com base nas características de consumo dos dispositivos, que viabilize comunicação direta D2D energeticamente mais eficiente que a comunicação convencional via estação rádio base. Em seguida, para cenários de grande aglomeração de pessoas, uma alternativa de serviço de disponibilização de conteúdos ou transferência de arquivos através de um novo padrão de alocação de recursos, utilizando o modo duplex por divisão no tempo (TDD – Time Duplex Division). Foram considerados cinco modelos de propagação distintos para comparação do desempenho, tomando como base uma situação real num parque do Recife considerando a transmissão de um vídeo em alta definição. Por fim, tratamos a questão da segurança com uma criptografia específica entre os dispositivos próximos. Os resultados são avaliados via simulação utilizando-se o Matlab, demonstrando a eficácia da solução com reduções de até 43% no consumo de energia da bateria do dispositivo.

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Ben, Mosbah Aziza. "Context-aware mechanisms for device discovery optimization." Thesis, Evry, Institut national des télécommunications, 2017. http://www.theses.fr/2017TELE0018/document.

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La recherche dans les réseaux de communication cherche à améliorer la capacité et les performances des technologies de réseaux tout en satisfaisant à la fois la demande croissante d’instantanéité des accès et des échanges d’information. Par exemple, les travaux sur les systèmes sans-fil de cinquième génération (5G) visent à augmenter le débit de données et l’efficacité spectrale mais aussi à réduire la latence et la consommation d’énergie. Dans ce contexte, la mise en réseau basée sur la proximité est envisagée afin d’améliorer l’échange d’information entre périphériques proches, même dans le cas où aucune infrastructure n’est disponible. Une composante essentielle de ces solutions est la capacité de rapidement détecter (ou découvrir) les autres systèmes à proximité. Bien que l’utilisation de la découverte des systèmes et de services ne soit pas à proprement parler une nouveauté dans les réseaux, son adoption dans les réseaux sans-fil a augmenté l’importance et la pertinence de ce type de mécanismes. Par conséquence, l’objectif de cette thèse est d’optimiser les performances du processus de découverte en utilisant des mécanismes contextuels. Dans un premier temps, nous commençons par une description préliminaire des défis auxquels sont confrontés les utilisateurs du réseau et comment les solutions actuelles (c’est-à-dire Long Term Evolution (LTE)) ne peuvent pas couvrir leurs besoins. Dans un deuxième temps, nous présentons l’architecture utilisée pour évaluer nos propositions: l’architecture appareil-à-appareil (D2D) qui est définie par le programme de partenariat de troisième génération (3GPP) pour être utilisée dans les réseaux LTE. Nous mettrons tout particulièrement l’accent sur la description du processus de découverte tel qu’il est défini dans les spécifications. Finalement, nous présentons une étude analytique, avec un modèle de mise en oeuvre pour tester et valider les performances de la découverte directe. En utilisant cette analyse, nous proposons un algorithme de transmission adaptatif qui optimise le processus de découverte pour les topologies statiques. Cette contribution sert de base à des algorithmes étendus et améliorés ciblant premièrement des scénarios où la disponibilité de données historiques permet de prédire les fluctuations de la densité des utilisateurs, et deuxièmement des situations entièrement dynamiques sans infrastructure ou support externe, montrant comment les mécanismes contextuels peuvent fournir des performances presque optimales. Toutes ces contributions et ces analyses sont supportées et validées par des modèles de simulation et des expériences qui montrent l’importance et l’exactitude de nos propositions dans l’optimisation de la performance et de la fiabilité dans le cadre de la découverte directe
Research in communication networks aims to improve the capabilities and performance of network technologies, and to satisfy the ever increasing demand for instant information access and exchange. For example, work on Fifth Generation (5G) Wireless Systems aims to increase data rates and spectral efficiency while lowering latency and energy consumption. Within this context, proximity-based networking is being considered in order to improve the data sharing between nearby devices, regardless of the availability of additional infrastructure. An integral component of these solutions is the ability to quickly detect (or discover) other systems in the vicinity. While system and service discovery has been a concept used in networks for some time, its adoption by wireless networks has increased the importance and relevance of this type of mechanisms. Therefore, the goal of this thesis is to optimize the performance of the discovery process by using context-aware mechanisms. First, we start by an introductory description of the challenges faced by network users and how current solutions (i.e. Long Term Evolution (LTE)) are unable to cover their needs. Second, we present the architecture we will use to evaluate our proposals, namely the device-to-device (D2D) architecture defined by the Third-Generation Partnership Program (3GPP) for use in LTE networks, with an emphasis on the description of the discovery process as defined in the standard specifications. Then, we present an analytical study, along with an implementation model to test and validate the performance of direct discovery. Building upon that analysis, we propose an adaptive transmission algorithm that optimizes the discovery process for static topologies. This contribution is used as the foundation for extended and enhanced algorithms targeting scenarios where the availability of historic data allows for predicting user density fluctuations, and fully dynamic situations without external infrastructure or support, showing how context-aware mechanisms can provide almost optimal performance. All these contributions and analysis are supported and validated by simulation models and experiments that showcase the importance and correctness of our proposals in the optimization of the performance and reliability in D2D direct discovery

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Silva, Carlos Filipe Moreira e. "Contemporary electromagnetic spectrum reuse techniques: tv white spaces and D2D communications." reponame:Repositório Institucional da UFC, 2015. http://www.repositorio.ufc.br/handle/riufc/15899.

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SILVA, C. F. M. Contemporary electromagnetic spectrum reuse techniques: tv white spaces and D2D communications. 128 f. 2015. Tese (Doutorado em Engenharia de Teleinformática) – Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2015.
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Over the last years, the wireless broadband access has achieved a tremendous success. With that, the telecommunications industry has faced very important changes in terms of technology, heterogeneity, kind of applications, and massive usage (virtual data tsunami) derived from the introduction of smartphones and tablets; or even in terms of market structure and its main players/actors. Nonetheless, it is well-known that the electromagnetic spectrum is a scarce resource, being already fully occupied (or at least reserved for certain applications). Tra- ditional spectrum markets (where big monopolies dominate) and static spectrum management originated a paradoxal situation: the spectrum is occupied without actually being used! In one hand, with the global transition from analog to digital Television (TV), part of the spectrum previously licensed for TV is freed and geographically interleaved, originating the consequent Television White Spaces (TVWS); on the other hand, the direct communications between devices, commonly referred as Device-to-Device (D2D) communications, are attracting crescent attention by the scientific community and industry in order to overcome the scarcity problem and satisfy the increasing demand for extra capacity. As such, this thesis is divided in two main parts: (a) Spectrum market for TVWS: where a SWOT analysis for the use of TVWS is performed giving some highlights in the directions/actions that shall be followed so that its adoption becomes effective; and a tecno-economic evaluation study is done considering as a use-case a typical European city, showing the potential money savings that operators may reach if they adopt by the use of TVWS in a flexible market manner; (b) D2D communications: where a neighbor discovery technique for D2D communications is proposed in the single-cell scenario and further extended for the multi-cell case; and an interference mitigation algorithm based on the intelligent selection of Downlink (DL) or Uplink (UL) band for D2D communications underlaying cellular networks. A summary of the principal conclusions is as follows: (a) The TVWS defenders shall focus on the promotion of a real-time secondary spectrum market, where through the correct implementation of policies for protection ratios in the spectrum broker and geo-location database, incumbents are protected against interference; (b) It became evident that an operator would recover its investment around one year earlier if it chooses to deploy the network following a flexible spectrum market approach with an additional TVWS carrier, instead of the traditional market; (c) With the proposed neighbor discovery technique the time to detect all neighbors per Mobile Station (MS) is significantly reduced, letting more time for the actual data transmission; and the power of MS consumed during the discovery process is also reduced because the main processing is done at the Base Station (BS), while the MS needs to ensure that D2D communication is possible just before the session establishment; (d) Despite being a simple concept, band selection improves the gains of cellular communications and limits the gains of D2D communications, regardless the position within the cell where D2D communications happen, providing a trade-off between system performance and interference mitigation.
Nos últimos anos, o acesso de banda larga atingiu um grande sucesso. Com isso, a indústria das telecomunicações passou por importantes transformações em termos de tecnologia, heterogeneidade, tipo de aplicações e uso massivo (tsunami virtual de dados) em consequência da introdução dos smartphones e tablets; ou até mesmo na estrutura de mercado e os seus principais jogadores/atores. Porém, é sabido que o espectro electromagnético é um recurso limitado, estando já ocupado (ou pelo menos reservado para alguma aplicação). O mercado tradicional de espectro (onde os grandes monopólios dominam) e o seu gerenciamento estático contribuíram para essa situação paradoxal: o espectro está ocupado mas não está sendo usado! Por um lado, com a transição mundial da Televisão (TV) analógica para a digital, parte do espectro anteriormente licenciado para a TV é libertado e geograficamente multiplexado para evitar a interferência entre sinais de torres vizinhas, dando origem a «espaços em branco» na frequência da TV ou Television White Spaces (TVWS); por outro lado, as comunicações diretas entre usuários, designadas por comunicações diretas Dispositivo-a-Dispositivo (D2D), está gerando um crescente interesse da comunidade científica e indústria, com vista a ultrapassar o problema da escassez de espectro e satisfazer a crescente demanda por capacidade extra. Assim, a tese está dividida em duas partes principais: (a) Mercado de espectro eletromagnético para TVWS: onde é feita uma análise SWOT para o uso dos TVWS, dando direções/ações a serem seguidas para que o seu uso se torne efetivo; e um estudo tecno-econômico considerando como cenário uma típica cidade Europeia, onde se mostram as possíveis poupanças monetárias que os operadores conseguem obter ao optarem pelo uso dos TVWS num mercado flexível; (b) Comunicações D2D: onde uma técnica de descoberta de vizinhos para comunicações D2D é proposta, primeiro para uma única célula e mais tarde estendida para o cenário multi-celular; e um algoritmo de mitigação de interferência baseado na seleção inteligente da banda Ascendente (DL) ou Descendente (UL) a ser reusada pelas comunicações D2D que acontecem na rede celular. Um sumário das principais conclusões é o seguinte: (a) Os defensores dos TVWS devem-se focar na promoção do mercado secundário de espectro electromagnético, onde através da correta implementação de politicas de proteção contra a interferência no broker de espectro e na base de dados, os usuários primário são protegidos contra a interferência; (b) Um operador consegue recuperar o seu investimento aproximadamente um ano antes se ele optar pelo desenvolvimento da rede seguindo um mercado secundário de espectro com a banda adicional de TVWS, em vez do mercado tradicional; (c) Com a técnica proposta de descoberta de vizinhos, o tempo de descoberta por usuário é significativamente reduzido; e a potência consumida nesse processo é também ela reduzida porque o maior processamento é feito na Estação Rádio Base (BS), enquanto que o usuário só precisa de se certificar que a comunicação direta é possível; (d) A seleção de banda, embora seja um conceito simples, melhora os ganhos das comunicações celulares e limita os das comunicações D2D, providenciando um compromisso entre a performance do sistema e a mitigação de interferência.

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Ben, Mosbah Aziza. "Context-aware mechanisms for device discovery optimization." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2017. http://www.theses.fr/2017TELE0018.

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La recherche dans les réseaux de communication cherche à améliorer la capacité et les performances des technologies de réseaux tout en satisfaisant à la fois la demande croissante d’instantanéité des accès et des échanges d’information. Par exemple, les travaux sur les systèmes sans-fil de cinquième génération (5G) visent à augmenter le débit de données et l’efficacité spectrale mais aussi à réduire la latence et la consommation d’énergie. Dans ce contexte, la mise en réseau basée sur la proximité est envisagée afin d’améliorer l’échange d’information entre périphériques proches, même dans le cas où aucune infrastructure n’est disponible. Une composante essentielle de ces solutions est la capacité de rapidement détecter (ou découvrir) les autres systèmes à proximité. Bien que l’utilisation de la découverte des systèmes et de services ne soit pas à proprement parler une nouveauté dans les réseaux, son adoption dans les réseaux sans-fil a augmenté l’importance et la pertinence de ce type de mécanismes. Par conséquence, l’objectif de cette thèse est d’optimiser les performances du processus de découverte en utilisant des mécanismes contextuels. Dans un premier temps, nous commençons par une description préliminaire des défis auxquels sont confrontés les utilisateurs du réseau et comment les solutions actuelles (c’est-à-dire Long Term Evolution (LTE)) ne peuvent pas couvrir leurs besoins. Dans un deuxième temps, nous présentons l’architecture utilisée pour évaluer nos propositions: l’architecture appareil-à-appareil (D2D) qui est définie par le programme de partenariat de troisième génération (3GPP) pour être utilisée dans les réseaux LTE. Nous mettrons tout particulièrement l’accent sur la description du processus de découverte tel qu’il est défini dans les spécifications. Finalement, nous présentons une étude analytique, avec un modèle de mise en oeuvre pour tester et valider les performances de la découverte directe. En utilisant cette analyse, nous proposons un algorithme de transmission adaptatif qui optimise le processus de découverte pour les topologies statiques. Cette contribution sert de base à des algorithmes étendus et améliorés ciblant premièrement des scénarios où la disponibilité de données historiques permet de prédire les fluctuations de la densité des utilisateurs, et deuxièmement des situations entièrement dynamiques sans infrastructure ou support externe, montrant comment les mécanismes contextuels peuvent fournir des performances presque optimales. Toutes ces contributions et ces analyses sont supportées et validées par des modèles de simulation et des expériences qui montrent l’importance et l’exactitude de nos propositions dans l’optimisation de la performance et de la fiabilité dans le cadre de la découverte directe
Research in communication networks aims to improve the capabilities and performance of network technologies, and to satisfy the ever increasing demand for instant information access and exchange. For example, work on Fifth Generation (5G) Wireless Systems aims to increase data rates and spectral efficiency while lowering latency and energy consumption. Within this context, proximity-based networking is being considered in order to improve the data sharing between nearby devices, regardless of the availability of additional infrastructure. An integral component of these solutions is the ability to quickly detect (or discover) other systems in the vicinity. While system and service discovery has been a concept used in networks for some time, its adoption by wireless networks has increased the importance and relevance of this type of mechanisms. Therefore, the goal of this thesis is to optimize the performance of the discovery process by using context-aware mechanisms. First, we start by an introductory description of the challenges faced by network users and how current solutions (i.e. Long Term Evolution (LTE)) are unable to cover their needs. Second, we present the architecture we will use to evaluate our proposals, namely the device-to-device (D2D) architecture defined by the Third-Generation Partnership Program (3GPP) for use in LTE networks, with an emphasis on the description of the discovery process as defined in the standard specifications. Then, we present an analytical study, along with an implementation model to test and validate the performance of direct discovery. Building upon that analysis, we propose an adaptive transmission algorithm that optimizes the discovery process for static topologies. This contribution is used as the foundation for extended and enhanced algorithms targeting scenarios where the availability of historic data allows for predicting user density fluctuations, and fully dynamic situations without external infrastructure or support, showing how context-aware mechanisms can provide almost optimal performance. All these contributions and analysis are supported and validated by simulation models and experiments that showcase the importance and correctness of our proposals in the optimization of the performance and reliability in D2D direct discovery

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Belouanas, Salah-Eddine. "Dissémination de contenus populaires et tolérants au délai dans les réseaux cellulaires." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066230/document.

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Les ressources cellulaires sont précieuses et doivent être préservées dès que possible. Dans cette thèse, nous abordons le problème de la dissémination de contenus dans un réseau cellulaire surchargé. La première partie présente SCoD (Scheduled Content Delivery), une stratégie de dissémination purement cellulaire qui exploite la mobilité des utilisateurs ainsi que leur tolérance aux délais afin d’effectuer des transmissions différées. SCoD attend que les utilisateurs se rassemblent autour d’un minimum de points d’accès afin que le nombre total de transmissions soit réduit. Pour déclencher des transmissions, SCoD repose sur différentes fonctions de décision qui déclenchent aux instants opportuns une transmission en multicast. La deuxième partie de cette thèse traite également le problème d’économie de ressources cellulaires, mais en l’attaquant sous un autre angle. Nous exploitons des communications D2D que nous associons au multicast pour réduire la charge sur l’infrastructure. Nous analysons les avantages des communications opportunistes dans le contexte d’un service de diffusion de contenus basé sur les abonnements des utilisateurs. Nous présentons nos résultats pour deux cas de figure. Tout d’abord, nous illustrons le bénéfice des communications D2D dans le cadre d’un processus de diffusion, où le coût d’une transmission opportuniste est négligeable par rapport à celui d’une transmission cellulaire. Nous considérons ensuite le cas où les utilisateurs doivent être indemnisés pour leur participation au processus de diffusion, et où il y a donc un compromis à trouver. Nous fournissons des lignes directrices dans ce sens et nous montrons la variation d’un tel compromis en fonction de plusieurs paramètres du réseau
Cellular resources are valuable and must be saved whenever possible. In this thesis, we address the problem of content dissemination within an overloaded cellular network. Firstly, we propose SCoD (Scheduled Content Delivery), a purely cellular dissemination strategy that exploits the mobility of users and their delay tolerance in order to postpone transmissions. SCoD waits for users to gather around a minimum number of access points so that the total number of transmissions is reduced. To trigger transmissions, SCoD relies on different decision functions which launch, if necessary, a multicast transmission. The second part of this thesis deals with the same problem of saving cellular resources, but from another angle. We use D2D (Device-to-Device) communications with multicast to mitigate the traffic load on the infrastructure. We study the benefits of opportunistic communications in the context of a content distribution service based on user subscriptions. We present our results in two ways. First, we illustrate the benefits of D2D communications in a content dissemination process where the cost of opportunistic transmission is negligible compared to that of cellular transmission. Then, we consider the case where users must be compensated for their participation in the dissemination process. Therefore, there is a tradeoff to be found, we thus provide guidelines in this direction and show the variation of such a tradeoff as a function of several network parameters

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Sonklin, Kachane. "Studies of communication and positioning performance of connected vehicles for safety applications." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/207089/1/Kachane_Sonklin_Thesis.pdf.

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Connected vehicles for safety applications play a significant role on reduction of the risks of road accidents. However, the performance of communication and positioning approaches is a major concern. This thesis establishes a connectivity framework based on publish-subscribe architecture for high-timeliness vehicle-to-vehicle data exchanges and determines the performance requirements for precise vehicle positioning for various safety use cases. Extensive experimental results demonstrated the performance benefits of the communication and positioning solutions for vehicle safety applications.

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Belouanas, Salah-Eddine. "Dissémination de contenus populaires et tolérants au délai dans les réseaux cellulaires." Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066230.pdf.

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Les ressources cellulaires sont précieuses et doivent être préservées dès que possible. Dans cette thèse, nous abordons le problème de la dissémination de contenus dans un réseau cellulaire surchargé. La première partie présente SCoD (Scheduled Content Delivery), une stratégie de dissémination purement cellulaire qui exploite la mobilité des utilisateurs ainsi que leur tolérance aux délais afin d’effectuer des transmissions différées. SCoD attend que les utilisateurs se rassemblent autour d’un minimum de points d’accès afin que le nombre total de transmissions soit réduit. Pour déclencher des transmissions, SCoD repose sur différentes fonctions de décision qui déclenchent aux instants opportuns une transmission en multicast. La deuxième partie de cette thèse traite également le problème d’économie de ressources cellulaires, mais en l’attaquant sous un autre angle. Nous exploitons des communications D2D que nous associons au multicast pour réduire la charge sur l’infrastructure. Nous analysons les avantages des communications opportunistes dans le contexte d’un service de diffusion de contenus basé sur les abonnements des utilisateurs. Nous présentons nos résultats pour deux cas de figure. Tout d’abord, nous illustrons le bénéfice des communications D2D dans le cadre d’un processus de diffusion, où le coût d’une transmission opportuniste est négligeable par rapport à celui d’une transmission cellulaire. Nous considérons ensuite le cas où les utilisateurs doivent être indemnisés pour leur participation au processus de diffusion, et où il y a donc un compromis à trouver. Nous fournissons des lignes directrices dans ce sens et nous montrons la variation d’un tel compromis en fonction de plusieurs paramètres du réseau
Cellular resources are valuable and must be saved whenever possible. In this thesis, we address the problem of content dissemination within an overloaded cellular network. Firstly, we propose SCoD (Scheduled Content Delivery), a purely cellular dissemination strategy that exploits the mobility of users and their delay tolerance in order to postpone transmissions. SCoD waits for users to gather around a minimum number of access points so that the total number of transmissions is reduced. To trigger transmissions, SCoD relies on different decision functions which launch, if necessary, a multicast transmission. The second part of this thesis deals with the same problem of saving cellular resources, but from another angle. We use D2D (Device-to-Device) communications with multicast to mitigate the traffic load on the infrastructure. We study the benefits of opportunistic communications in the context of a content distribution service based on user subscriptions. We present our results in two ways. First, we illustrate the benefits of D2D communications in a content dissemination process where the cost of opportunistic transmission is negligible compared to that of cellular transmission. Then, we consider the case where users must be compensated for their participation in the dissemination process. Therefore, there is a tradeoff to be found, we thus provide guidelines in this direction and show the variation of such a tradeoff as a function of several network parameters

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Kalalas, Charalampos. "Cellular networks for smart grid communication." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/620760.

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The next-generation electric power system, known as smart grid, relies on a robust and reliable underlying communication infrastructure to improve the efficiency of electricity distribution. Cellular networks, e.g., LTE/LTE-A systems, appear as a promising technology to facilitate the smart grid evolution. Their inherent performance characteristics and well-established ecosystem could potentially unlock unprecedented use cases, enabling real-time and autonomous distribution grid operations. However, cellular technology was not originally intended for smart grid communication, associated with highly-reliable message exchange and massive device connectivity requirements. The fundamental differences between smart grid and human-type communication challenge the classical design of cellular networks and introduce important research questions that have not been sufficiently addressed so far. Motivated by these challenges, this doctoral thesis investigates novel radio access network (RAN) design principles and performance analysis for the seamless integration of smart grid traffic in future cellular networks. Specifically, we focus on addressing the fundamental RAN problems of network scalability in massive smart grid deployments and radio resource management for smart grid and human-type traffic. The main objective of the thesis lies on the design, analysis and performance evaluation of RAN mechanisms that would render cellular networks the key enabler for emerging smart grid applications. The first part of the thesis addresses the radio access limitations in LTE-based networks for reliable and scalable smart grid communication. We first identify the congestion problem in LTE random access that arises in large-scale smart grid deployments. To overcome this, a novel random access mechanism is proposed that can efficiently support real-time distribution automation services with negligible impact on the background traffic. Motivated by the stringent reliability requirements of various smart grid operations, we then develop an analytical model of the LTE random access procedure that allows us to assess the performance of event-based monitoring traffic under various load conditions and network configurations. We further extend our analysis to include the relation between the cell size and the availability of orthogonal random access resources and we identify an additional challenge for reliable smart grid connectivity. To this end, we devise an interference- and load-aware cell planning mechanism that enhances reliability in substation automation services. Finally, we couple the problem of state estimation in wide-area monitoring systems with the reliability challenges in information acquisition. Using our developed analytical framework, we quantify the impact of imperfect communication reliability in the state estimation accuracy and we provide useful insights for the design of reliability-aware state estimators. The second part of the thesis builds on the previous one and focuses on the RAN problem of resource scheduling and sharing for smart grid and human-type traffic. We introduce a novel scheduler that achieves low latency for distribution automation traffic while resource allocation is performed in a way that keeps the degradation of cellular users at a minimum level. In addition, we investigate the benefits of Device-to-Device (D2D) transmission mode for event-based message exchange in substation automation scenarios. We design a joint mode selection and resource allocation mechanism which results in higher data rates with respect to the conventional transmission mode via the base station. An orthogonal resource partition scheme between cellular and D2D links is further proposed to prevent the underutilization of the scarce cellular spectrum. The research findings of this thesis aim to deliver novel solutions to important RAN performance issues that arise when cellular networks support smart grid communication.
Las redes celulares, p.e., los sistemas LTE/LTE-A, aparecen como una tecnología prometedora para facilitar la evolución de la próxima generación del sistema eléctrico de potencia, conocido como smart grid (SG). Sin embargo, la tecnología celular no fue pensada originalmente para las comunicaciones en la SG, asociadas con el intercambio fiable de mensajes y con requisitos de conectividad de un número masivo de dispositivos. Las diferencias fundamentales entre las comunicaciones en la SG y la comunicación de tipo humano desafían el diseño clásico de las redes celulares e introducen importantes cuestiones de investigación que hasta ahora no se han abordado suficientemente. Motivada por estos retos, esta tesis doctoral investiga los principios de diseño y analiza el rendimiento de una nueva red de acceso radio (RAN) que permita una integración perfecta del tráfico de la SG en las redes celulares futuras. Nos centramos en los problemas fundamentales de escalabilidad de la RAN en despliegues de SG masivos, y en la gestión de los recursos radio para la integración del tráfico de la SG con el tráfico de tipo humano. El objetivo principal de la tesis consiste en el diseño, el análisis y la evaluación del rendimiento de los mecanismos de las RAN que convertirán a las redes celulares en el elemento clave para las aplicaciones emergentes de las SGs. La primera parte de la tesis aborda las limitaciones del acceso radio en redes LTE para la comunicación fiable y escalable en SGs. En primer lugar, identificamos el problema de congestión en el acceso aleatorio de LTE que aparece en los despliegues de SGs a gran escala. Para superar este problema, se propone un nuevo mecanismo de acceso aleatorio que permite soportar de forma eficiente los servicios de automatización de la distribución eléctrica en tiempo real, con un impacto insignificante en el tráfico de fondo. Motivados por los estrictos requisitos de fiabilidad de las diversas operaciones en la SG, desarrollamos un modelo analítico del procedimiento de acceso aleatorio de LTE que nos permite evaluar el rendimiento del tráfico de monitorización de la red eléctrica basado en eventos bajo diversas condiciones de carga y configuraciones de red. Además, ampliamos nuestro análisis para incluir la relación entre el tamaño de celda y la disponibilidad de recursos de acceso aleatorio ortogonales, e identificamos un reto adicional para la conectividad fiable en la SG. Con este fin, diseñamos un mecanismo de planificación celular que tiene en cuenta las interferencias y la carga de la red, y que mejora la fiabilidad en los servicios de automatización de las subestaciones eléctricas. Finalmente, combinamos el problema de la estimación de estado en sistemas de monitorización de redes eléctricas de área amplia con los retos de fiabilidad en la adquisición de la información. Utilizando el modelo analítico desarrollado, cuantificamos el impacto de la baja fiabilidad en las comunicaciones sobre la precisión de la estimación de estado. La segunda parte de la tesis se centra en el problema de scheduling y compartición de recursos en la RAN para el tráfico de SG y el tráfico de tipo humano. Presentamos un nuevo scheduler que proporciona baja latencia para el tráfico de automatización de la distribución eléctrica, mientras que la asignación de recursos se realiza de un modo que mantiene la degradación de los usuarios celulares en un nivel mínimo. Además, investigamos los beneficios del modo de transmisión Device-to-Device (D2D) en el intercambio de mensajes basados en eventos en escenarios de automatización de subestaciones eléctricas. Diseñamos un mecanismo conjunto de asignación de recursos y selección de modo que da como resultado tasas de datos más elevadas con respecto al modo de transmisión convencional a través de la estación base. Finalmente, se propone un esquema de partición de recursos ortogonales entre enlaces celulares y D2

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Mašek, Pavel. "Heterogenní propojení mobilních zařízení v bezdrátových systémech 5. generace." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-358407.

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Předkládaná disertační práce je zaměřena na "heterogenní propojení mobilních zařízení v bezdrátových systémech 5. generace". Navzdory nepochybnému pokroku v rámci navržených komunikačních řešení postrádají mobilní sítě nastupující generace dostatečnou šířku pásma a to hlavně kvůli neefektivnímu využívání rádiového spektra. Tato situace tedy v současné době představuje řadu otázek v oblasti výzkumu. Hlavním cílem této disertační práce je proto návrh nových komunikačních mechanismů pro komunikaci mezi zařízeními v bezprostřední blízkosti s asistencí mobilní sítě a dále pak návrh a implementace algoritmů pro dynamické přidělování frekvenčního spektra v nastupujících mobilních sítích 5G. Navrhnuté komunikační mechanismy a algoritmy jsou následně komplexně vyhodnoceny pomocí nově vyvinutých simulačních nástrojů (kalibrovaných s využitím 3GPP trénovacích dat) a zejména pak v experimentální mobilní síti LTE-A, která se nachází v prostorách Vysokého učení technického v Brně, Česká Republika. Získané praktické výsledky, které jsou podpořeny zcela novou matematickou analýzou ve speciálně navržených charakteristických scénářích, představují řešení pro vlastníka spektra v případě požadavků na jeho dynamické sdílení. Tato metoda tedy představuje možnost pro efektivnější využití spektra v rámci mobilních sítí 5G bez degradace kvality služeb (QoS) a kvality zážitků (QoE) pro koncové uživatele. Vědecký přínos dosažených výsledků dokazuje fakt, že některé z principů představených v této disertační práci byly zahrnuty do celosvětově uznávaného standardu (specifikace) 3GPP Release 12.

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Conceicao, Filipe. "Network survival with energy harvesting : secure cooperation and device assisted networking." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLL020/document.

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La technologie de réseau cellulaire de 5ème génération (5G) sera le réseau supportant l'Internet des objets (IoT). Elle a introduit une fonctionnalité majeure, communications appareil-à-appareil (D2D), que permettent communications sans fil à consommation d'énergie restreinte en interagissant à proximité et à puissance d'émission plus faible. La coopération entre appareils suscit donc un intérêt considérable pour l'énergie, et peut être utilisé en conjonction avec la récupération d'énergie pour prolonger la durée de vie des appareils. Les programmes de coopération renforcent la mise en réseau d'un appareil à l'autre, ce qui accroît la nécessité d'exécuter des mécanismes de sécurité pour assurer la protection des données et les relations de confiance entre les nœuds du réseau.Ces mécanismes sont fondamentaux pour la protection contre les attaques malveillantes mais elles représentent aussi une importante consommation d'énergie, souvent négligée en raison de l'importance de la protection des données. L'établissement d'un canal securisé peut être coûteux en termes d'utilisation du CPU, la mémoire et la consommation d'énergie, surtout si les appareils sont limités en ressources. La confidentialité et l’intégrité des données ont un faible coût énergétique, mais sont utilisées en permanence. Il est donc nécessaire de quantifier la consommation d'énergie engendrée par la sécurité d'un appareil. Un modèle énergétique basé sur la sécurité est proposé pour répondre à cet objectif.Dans les réseaux composés d'équipements d'utilisateurs (UE), la mobilité est une caractéristique clé. Elle peut agir sur la connexion à proximité d'objets IoT, étendant la couverture 5G vers l'IoT via les UEs. Une solution d'authentification légère est présentée qui permet par l'authentification directe et des communications UE-IoT, d'étendre la couverture et réaliser des économies d'énergie potentielles importantes. Cette approche peut être particulièrement utile en cas de catastrophe où l'infrastructure réseau peut ne pas être disponible.La condentialité et l'authentification des données sont une source de consommation d'énergie importante. Les appareils équipés avec équipements de collecte d'énergie (EH) peuvent avoir un excédent ou un déficit d'énergie. La sécurité appliquée peut donc être ajustée en fonction de l'énergie disponible d'un appareil, en introduisant l'établissement de canal sécurisé qui tient compte de la consommation d'énergie. Après avoir étudié en profondeur les normes 5G, il a été constaté que les réseaux d'UE D2D utilisant ce type de norme dépenseraient une quantité importante d'énergie et seraient généralement moins sûr. Un mécanisme léger de recléage est donc proposé pour réduire les coûts liés cette adaptation. Pour compléter le concept de canal sécurisé prenant en compte l'énergie et le mécanisme de recléage, une méthode de bootstrapping des paramètres de sécurité est également présentée. Le méthode désigne le cœur du réseau (CN) comme responsable de la politique de sécurité, rend l'ensemble du réseau plus sûr et aide à prévenir les pannes de communication. L'adaptation susvisé requiert l'étude du compromis entre l’énergie et sécurité. À cette fin, un processus décisionnel de Markov (MDP) modélisant un canal de communication est présenté lorsqu'un agent choisit les éléments de sécurité à appliquer aux paquets transmis. Ce problème d'optimisation du contrôle stochastique est résolu par plusieurs algorithmes de programmation dynamique et d’apprentissage par le renforcement (RL). Les résultats montrent que l'adaptation susvisé peut prolonger de manière significative la durée de vie de l'équipement et de la batterie, et améliore la fiabilité des données tout en offrant des fonctions de sécurité. Une étude comparative est présentée pour les différents algorithmes RL. Puis une approche d'apprentissage Q-profond (DQL) est proposé que améliore la vitesse d'apprentissage de l'agent et la fiabilité des données
The 5th Generation Cellular Network Technology (5G) will be the network supporting the Internet of Things (IoT) and it introduced a major feature, Device-to-Device (D2D) communications. D2D allows energy-constrained wireless devices to save energy by interacting in proximity at a lower transmission power. Cooperation and device-assisted networking therefore raise signicant interest with respect to energy saving, and can be used in conjunction with energy harvesting to prolong the lifetime of battery-powered devices. However, cooperation schemes increase networking between devices, increasing the need for security mechanisms to be executed to assure data protection and trust relations between network nodes. This leads to the use of cryptographic primitives and security mechanisms with a much higher frequency.Security mechanisms are fundamental for protection against malicious actions but they also represent an important source of energy consumption, often neglected due to the importance of data protection. Authentication procedures for secure channel establishment can be computationally and energetically expensive, especially if the devices are resource constrained. Security features such as condentiality and data authentication have a low energetic cost but are used constantly in a device engaged in data exchanges. It is therefore necessary to properly quantify the energy consumption due to security in a device. A security based energy model is proposed to achieve this goal.In User Equipment (UE) D2D networks, mobility is a key characteristic. It can be explored for connecting directly in proximity with IoT objects. A lightweight authentication solution is presented that allows direct UE-IoT communications, extending coverage and potentially saving signicant energy amounts. This approach can be particularly useful in Public Protection and Disaster Relief (PPDR) scenarios where the network infrastructure may not be available.Security features such as condentiality or data authentication are a significant source of consumption. Devices equipped with Energy Harvesting (EH) hardware can have a surplus or a deficit of energy. The applied security can therefore be adjusted to the available energy of a device, introducing an energy aware secure channel. After in depth analysis of 5G standards, it was found that D2D UE networks using this type of channel would spend a signicant amount of energy and be generally less secure. A lightweight rekeying mechanism is therefore proposed to reduce the security overhead of adapting security to energy. To complete the proposed rekeying mechanism, a security parameter bootstrapping method is also presented. The method denes the Core Network (CN) as the security policy maker, makes the overall network more secure and helps preventing communication outages.Adapting security features to energy levels raises the need for the study of the energy/security tradeoff. To this goal, an Markov Decision Process (MDP) modeling a communication channel is presented where an agent chooses the security features to apply to transmitted packets. This stochastic control optimization problem is solved via several dynamic programming and Reinforcement Learning (RL) algorithms. Results show that adapting security features to the available energy can signicantly prolong battery lifetime, improve data reliability while still providing security features. A comparative study is also presented for the different RL learning algorithms. Then a Deep Q-Learning (DQL) approach is presented and tested to improve the learning speed of the agent. Results confirm the faster learning speed. The approach is then tested under difficult EH hardware stability. Results show robust learning properties and excellent security decision making from the agent with a direct impact on data reliability. Finally, a memory footprint comparison is made to demonstrate the feasibility of the presented system even on resource constrained devices

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Komaragiri, Shalini Sushmitha. "A SAG monitoring device based on a cluster of code-based GPS receivers : a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2009. http://proquest.umi.com/pqdweb?index=0&did=2000377771&SrchMode=1&sid=2&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1277472835&clientId=28564.

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Segundo, Edvaldo de Sousa Soares. "Interferência em comunicações Device-to-Device D2D." Master's thesis, 2017. http://hdl.handle.net/10071/15102.

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A constante necessidade de aumento da capacidade de rede para atender às crescentes demandas dos assinantes, leva a indústria de telecomunicações, apoiada pela comunidade científica, a criar novos paradigmas que suportem requisitos de taxa de dados binários elevados dentro da rede de acesso sem fio existente de forma eficiente e eficaz. Para responder a este desafio, a Comunicação Device-to-Device (D2D) em redes celulares é vista como uma solução promissora. Deste modo, a presente dissertação consiste na exploração do modelo de comunicação D2D (Device-to-Device), mediante o desenvolvimento de várias rotinas de comunicação D2D dentro de uma estrutura de rede celular LTE-A, usando simuladores já existentes, nomeadamente, simuladores de sistema em JAVA e simuladores de ligação em MatLab, afim de analisar o eventual aumento de capacidade da comunicação D2D para rede celular. Tipicamente, as comunicações em D2D permitem que os utilizadores localizados na proximidade, possam comunicar diretamente sem a intervenção da estação base (BS - Base Station). Essa comunicação pode permitir ritmos binários muito elevados, baixos atrasos e poupança de energia. Nesta dissertação alterou-se o simulador de sistema celular existente para incluir as comunicações D2D e as suas interferências, sendo apresentados os resultados obtidos. Os resultados obtidos por simulação confirmaram o que se esperava, nomeadamente, aumento dos ritmos binários nas comunicações D2D e redução do atraso.
The continuing need to increase network capacity to meet growing subscriber demands leads the telecommunications industry, backed by the scientific community, to create new paradigms that support high binary data rate requirements within the existing wireless access network efficiently and effectively. To meet this challenge, Device-toDevice (D2D) Communication in cellular networks is seen as a promising solution. Thus, the present dissertation consists of the exploitation of the D2D (Device-toDevice) communication model, by developing several D2D communication routines within a LTE-A cellular network structure, using existing simulators, namely, simulator of system in JAVA and simulator of link in MatLab, in order to analyze the possible increase of capacity of D2D communication for cellular network. Typically, D2D communications allow users located in close proximity to communicate directly without the intervention of the base station (BS - Base Station). This communication can allow very high binary rates, low delays and energy savings. In this dissertation, the existing cellular system simulator was modified to include D2D communications and their interference, and the results obtained were presented. Simulation results have confirmed what was expected, namely, increasing bit rate with D2D communications and lower delays.

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34

Hu, Chia-Wei, and 胡家維. "Interference-Aware Device-to-Device (D2D) Mode selection." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/49069984592961086957.

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碩士
國立交通大學
電子研究所
105
In this work, we consider device-to-device (D2D) communication underlaying a cellular network and focus on the mode selection of the new arrival D2D pair with existing D2D pairs. We also utilize two mode selection rules which is based on signal to interference noise ratio (SINR) and capacity. Each selection rule are discussed with two different sets of precoders. The first set is block diagonalization (BD) precoder for cellular users and zero forcing (ZF) precoder for D2D users. The second set is signal-to-leakage-and-noise ratio (SLNR) precoder with two different derivations for cellular users and D2D pairs, respectively. Our evaluation results show that utilizing SLNR precoders can not only achieve a suboptimal performance but also require much less limitations than BD and ZF. The simulation also shows that underlay mode is the best mode for new arrival D2D pair whether the existing D2D pairs are in underlay or overlay mode. In addition, resource allocation is a critical factor for improving the sum rate of the whole cell.

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35

Yang, Zhu-Jun, and 楊筑鈞. "Device-to-Device (D2D) Communication in LTE-A Networks." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/00095267393842233559.

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碩士
國立臺灣大學
電信工程學研究所
101
With the prevalence of mobile devices such as smart phones and tablets, people can access the Internet and use various applications and services anytime, anywhere. However, the existing 3rd generation (3G) cellular technologies cannot support the large demand of high-speed transmission. To support higher throughput and better quality of service, long term evolution advanced (LTE-A) has been proposed by 3rd Generation Partnership Project (3GPP). Device-to-device (D2D) communication is one of the key technologies in LTE-A for improving network capacity and resource utilization. With D2D communication, data transmission can be more efficient and thus the overall system capacity can be increased since the data does not go through the infrastructure. Furthermore, there are many opportunities for D2D communication. For example, location-based services and proximity social applications with D2D communication can use less resource and produce smaller latency. Although D2D can bring many benefits, there are still many challenges to implement D2D in LTE-A networks. From operators'' perspective, D2D would not be an appealing technology if no additional revenue can be generated. From user equipments'' perspective, D2D transmission can only be enabled if the UEs in the vicinity can be discovered. In this thesis, we consider D2D communication from both operator''s and UEs'' perspective. First, we derive the demand functions of pay-as-you-use and flat-rate plans, and analyze the revenue of an operator. Our numerical analysis and simulation results show that D2D not only increases nearly 1/3 of capacity but also brings up to 21% additional revenue for operators. The results provide operators with a strong incentive to implement D2D communication. Next, a random-access discovery protocol is proposed for UEs to discover other nearby UEs. The proposed protocol requires UEs to advertise their presence by random beacon transmission. In order to minimize resource consumption on discovery, an adaptive resource allocation algorithm based on the number of requesting D2D UEs is also proposed. Our numerical analysis and simulation results show that a very high discovery probability (e.g., 0.99) can be achieved by using only 1% of the eNB''s uplink resources.

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36

Alam, M., D. Yang, Jonathan Rodriguez, and Raed A. Abd-Alhameed. "Secure device-to-device communication in LTE-A." 2014. http://hdl.handle.net/10454/8061.

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no
Enabling D2D communications over LTE-A networks can provide many benefits in terms of throughput, energy consumption, traffic load, and so on. It also enables new commercial services such as location-based advertising. For these reasons, D2D communications has become a hot topic in both the academic and industrial communities. However, many research works are focused on node discovery, radio resource management, and other aspects, while the issue of security is less addressed. In this article, we intend to provide an overview of the security architecture, threads, and requirements. Based on these requirements, we propose several potential solutions by reusing the existing security mechanisms. Promising topics related to secure D2D communications for future research are also discussed.

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37

Huang, Kuo-Chen, and 黃國禎. "Utilizing Device-to-Device (D2D) Communications for Resource and Neighbor Discovery." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/40402292994561066060.

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碩士
國立交通大學
網路工程研究所
101
In Device-to-Device (D2D) communications, devices can communicate with each other directly. Although industry and academia are actively pursuing research in D2D communications, a frequently asked question is that why operators should buy in the idea of D2D communications because operators may loss control of devices. In this thesis, we propose an efficient resource discovery algorithm to demonstrate the benefit of D2D communications in 3GPP networks. The algorithm first dynamically groups devices. We then apply Distributed Hash Table (DHT) to reduce the resource discovery time. When a device needs a resource, it discovers the resource in its own group first. If the resource is found in the group, the device does not need to query servers in core network to get the resource. After a device finds the resource, the resource will be cached in the group. Therefore, other devices in the group can find the resource immediately. If the resource is not found in the group, the device has to query server to get the resource. It will make the resource discovery time longer than query server directly. Therefore, we propose to analyze the performance to help network operators to make decision whether the devices should query the resources in the group first. The proposed algorithm and performance analysis are verified by using extensive simulations. D2D communications also can be used in pedestrian collision avoidance. Based on our prior work, we have proposed a Wi-Fi pedestrian collision avoidance system. In the system, pedestrian's device acts as an WiFi AP and periodically sends beacons which include GPS and time information. The car which receives the beacon will detect whether there are pedestrians on its way. If there are, the system will warn the driver. Therefore, the system can avoid pedestrian collision. We analyze the performance which is validated by extensive simulations.

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38

Lan, Chen-Wei, and 藍振瑋. "Device-to-Device (D2D) Synchronization Approach in Public Safety Scenarios without Network Coverage." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/793cjb.

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碩士
國立交通大學
電信工程研究所
103
In this thesis, we proposed an approach of D2D synchronization procedure for out-of-coverage scenario. When all of the cellular nodes become fail due to public disaster situations, it is likely that some eNBs are unable to serve UEs and in out-of-coverage scenario, but we can use the D2D direct communication or broadcast communication to deliver information about public safety requirement. Synchronization procedure is important factor that affects performance of communication. Therefore, our goals of D2D synchronization approach are to enlarge the synchronization area for D2D communication and reduce the number of asynchronous timing synchronization sources surrounding a device. The simulation results show our goals are achieved successfully.

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39

Bie, Yi-Kai, and 白逸凱. "A Device-to-Device (D2D) Clustering Strategy for Multicast Transmission in LTE Networks." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/41630486851955795894.

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碩士
國立交通大學
電信工程研究所
103
In this thesis, a clustering strategy for multicast transmission in Device-to-Device (D2D) communication integrated into LTE networks is proposed to decrease maximum transmission time. Through mathematical analysis, we can select some user equipment (UE) as cluster head (CH) who is capable of distributing data to its members by multicast transmission, and arrange their members appropriately to decrease maximum transmission time. The simulation result shows that the clustering strategy decrease maximum transmission time, as well as average transmission time significantly.

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40

Yang, Shu-Hao, and 楊書豪. "Network-Assisted Device-Decided Resource Management for Multi-pair Device-to-Device (D2D) Communications in Heterogeneous Networks." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/ddyg93.

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41

Elsemary, Hadeer. "Secure Routing in Intelligent Device-to-Device Communications." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-002B-7CC7-3.

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42

Huang, Jie-Cheng, and 黃詰程. "Comparisons of Device-to-Device (D2D) Communication and Small Cells in LTE-A Networks." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/57576175014353895115.

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碩士
國立臺灣大學
電信工程學研究所
102
Thanks to the prevalence of mobile devices, various wireless applications and services such as online social networking and video streaming are developed and deployed. However, the continuous growth of data demand from these applications and services can no longer be supported by the existing wireless solutions. Long-Term Evolution (LTE) was proposed by the 3rd Generation Partnership Project (3GPP) in the Release 8 as a new network standard to solve this problem. After the Release 10, LTE becomes LTE-Advanced (LTE-A), which is regarded as the 4G standard nowadays. In LTE-A, new technologies, such as device-to-device (D2D) communication and small cells, are proposed to address the growing data demand. Take D2D communication as an example. Devices in the proximity of each other can communicate directly via a D2D link. Therefore, fewer radio resources are needed. Take small cell as another example. Small base stations (SBSs) can be deployed for increasing resource reutilization by providing better link quality. Although both D2D communication and small cells can improve resource utilization of LTE-A networks, the latter seems to attract more attentions since communicating UEs are not limited to be in the proximity of each other. However, deploying SBSs incurs a substantial amount of equipment and deployment expenses. Compared with small cells, D2D communication is a ``cheaper solution". Therefore, joint consideration of both technologies may reduce the overall cost while the same performance is achieved. In this thesis, different parameters, such as small cell coverage ratios, traffic patterns of UEs, etc., are used to evaluate both technologies. Our simulation shows that with the help of D2D communication, up to 33% reductions in term of the number of SBSs deployed can be achieved even when most communication links are not proximity links.

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43

Chen, Po-Hsun, and 陳柏勳. "Resource Allocation for Device-to-Device(D2D) Communication by Grouping in Underlaying Cellular Networks." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/11082639579312995070.

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碩士
國立交通大學
電信工程研究所
104
Device-to-Device (D2D) communication is an important topic in the future because it can improve the performance of cellular networks. The advantages of D2D communications include spectral efficiency, traffic offloading, cell coverage, throughput enhancement, etc. However, the impact of interferences between D2D pairs or D2D pair and cellular user cannot be ignored, so we need to provide an adequate solution for this problem. In this thesis, we proposed a method for a D2D pair to find the most appropriate cellular user whose uplink resource can be shared with the D2D pair. The proposed algorithm not only guarantees that the Signal to Interference plus Noise Ratio (SINR) at each D2D link and cellular link is higher than predefined threshold but also enhances the throughput of the whole system.

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44

Ma, Guoqing. "Privacy Concerned D2D-Assisted Delay-Tolerant Content Distribution System." Thesis, 2019. http://hdl.handle.net/10754/632512.

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It is foreseeable that device-to-device (D2D) communication will become a standard feature in the future, for the reason that it offloads the data traffic from network infrastructures to user devices. Recent researches prove that delivering delay-tolerant contents through content delivery network (CDN) by D2D helps network operators increase spectral and energy efficiency. However, protecting the private information of mobile users in D2D assistant CDN is the primary concern, which directly affects the willingness of mobile users to share their resources with others. In this thesis, we proposed a privacy concerned top layer system for selecting the sub-optimal set of mobile nodes as initial mobile content provider (MCP) for content delivery in any general D2D communications, which implies that our proposed system does not rely on private user information such as location, affinity, and personal preferences. We model the initial content carrier set problem as an incentive maximization problem to optimize the rewards for network operators and content providers. Then, we utilized the Markov random field (MRF) theory to build a probabilistic graphical model to make an inference on the observation of delivered contents. Furthermore, we proposed a greedy algorithm to solve the non-linear binary integer programming (NLBIP) problem for selecting the optimal initial content carrier set. The evaluations of the proposed system are based on both a simulated dataset and a real-world collected dataset corresponding to the off-line and on-line scenarios.

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45

TSAO, CHUN-YANG, and 曹竣揚. "Energy-Efficient and Fair Resource Allocation for Multi-Pair Device-to-Device (D2D) Communication Networks." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7aj6q7.

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碩士
國防大學理工學院
電子工程碩士班
107
The development of wireless communication technology has brought convenience to our lives. As people rely more and more on wireless communications, and the media traffic continues to rise, the spectrum resource is insufficient to be used. Thanks to the emergence of the device-to-device (D2D) communication technology, the problem can be effectively solved and the user experience can be improved. D2D communication is controlled by the cellular communication system and allows users to link directly without going through the base station. D2D communication can increase the spectrum efficiency and capacity for the cellular communication system. In the thesis, we provide a new resource block (RB) allocation method, named as rate-fair (RF) algorithm, to guarantee the QoS (quality of service) of both D2D users and macrocell users, and to ensure the fairness among the D2D pairs, simultaneously. In order to maximize the spectrum efficiency, we suggest that different D2D pairs can reuse an RB at the same time. In addition, we propose an avoidable interference (AI) algorithm to avoid the interference among D2D pairs. In the case of the RF algorithm combined with the AI algorithm, the transmission capacity of D2D system with reusing scheme is about 400% higher than that without resuing scheme. Therefore, we can trade 10% transmission capacity off for improving 6.5% D2D fairness, so that the fairness index of the D2D pairs can be achieved to 0.8 above.

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46

Hassan, Osama. "On Using D2D Collaboration and a DF-CF Relaying Scheme to Mitigate Channel Interference." Thesis, 2020. http://hdl.handle.net/10754/666290.

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Given the exponentially increasing number of connected devices to the network which will lead to a larger number of installed celluar towers and base stations that are in closer proximity to one another when compared to the current cellular network setup, and the increasing demand of higher data rates by end users, it becomes essential to investigate new methods that will more effectively mitigate the larger interference introduced by the more packed celluar grid and that result in higher data rates. This paper investigates using Device-to-Device communication where neighboring users can cooperate to mitigate the correlated interference they both receive, where one user acts as a relay and the other as the intended destination of a broadcast message sent by the source base station. The setup studied utalizes a non-orthogonal multiple access (NOMA) scheme and a combined decode-forward and compress-forward relaying scheme. We show that this combined scheme outperforms the individual schemes for some channels and network setups, or reduces to either scheme when the combination does not offer any achievable rate gains. The performance of each scheme is measured with respect to the locations of the base station and the two devices, and to the capacity of the digital link between the users.

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47

Guan-shiunCheng and 程冠勳. "Device-to-Device (D2D) based Congestion Reduction Mechanism for M2M Communication over the LTE-A Network." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/65204995308291838726.

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碩士
國立成功大學
資訊工程學系
102
The Long Term Evolution-Advanced cellular network is designed for human-to-human (H2H) communication. When a large number of machine-to-machine (M2M) devices are trying to access the network simultaneously, it leads to a low random access (RA) successful rate and high congestion problem, which may cause the waste of radio resources, packet loss, latency, extra power consumption, and the worst, M2M service error. There is an urge to propose an efficient method for M2M communication on the LTE-A network to resolve the congestion problem. In this study, we propose a congestion reduction mechanism, which can analyze and model the RA procedure on the LTE-A network, to find out the collapse point in the RA procedure and then design a scheme named D2D cooperative relay scheme to relieve the congestion problem. Meanwhile, this work also adds a relay access barring algorithm to improve performance and a RA resource separation mechanism for H2H communication. The proposed method can effectively reduce the network congestion problem. Simulation results show that the network throughput and the congestion can be significantly improved using the proposed mechanism.

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48

Hsing-HanChen and 陳星翰. "The MEC-based Load Balance Method for Device to Device (D2D) Communication over the Multiple Channel Environment." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/q54hd9.

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49

Gorantla, Bala Venkata Ramulu. "Efficient Resource Allocation for Underlay Device-to-device Communication Networks with Limited Channel State Information." Thesis, 2022. https://etd.iisc.ac.in/handle/2005/5861.

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Device-to-device (D2D) communication is finding applications in future wireless networks such as vehicular networks and internet-of-things. It offloads traffic from the base station (BS), improves energy efficiency, and reduces latency by enabling direct communication between the users. In underlay D2D, the D2D users share subchannels with the cellular users (CUs). While this improves spatial reuse, it causes interference between the D2D users and CUs. Hence, interference-aware resource allocation is an important research problem for underlay D2D networks. In this thesis, we consider a practically feasible partial CSI model in which the BS only knows the channel state information (CSI) of the CU-to-BS and D2D Receiver (DRx)-to-BS links. The D2D pair knows the CSI of the D2D transmitter (DTx)-to-DRx and CU-to-DRx links, and the statistics of inter-D2D and inter-cell interference powers. We propose a feedback model in which the DRx computes the signal-to-interference-plus-noise ratio (SINR) estimate and feeds a quantized version of it back to the BS. The SINR estimate is such that the corresponding rate has an outage probability within a pre-specified value. We first consider a subchannel allocation problem in which at most K D2D pairs are allowed to share a subchannel and a minimum rate with a pre-specified probability of outage is guaranteed for the CUs. We propose a polynomial-time algorithm called cardinality-constrained subchannel assignment algorithm (CCSAA) based on a submodular maximization approach. We prove that it gives a D2D sum rate that is at least one-third of the optimal D2D sum rate. We also propose a lower-complexity locally greedy algorithm (LGA) that provides the same theoretical guarantee but is applicable when K is equal to the number of D2D pairs. We then propose a modification of LGA called cardinality-constrained LGA (CCLGA) that applies to all values of K. We propose a rate upgradation scheme employed at the D2D pair to improve the D2D rate after subchannel allocation by exploiting the asymmetry in the rate information at the BS and the D2D pairs. Next, we consider a statistical CSI model in which the DRx computes and feeds back the SINR estimate by knowing only the statistics of the CSI of DTx-to-DRx, CU-to-DRx links, and the inter-cell and inter-D2D interference powers. We propose a relaxation-pruning algorithm (RPA) based on a linear program relaxation and rounding approach. It provides a D2D sum rate that is at least half of the optimal D2D sum rate. We present numerical results to investigate the interplay between the CSI model and resource allocation algorithm design by considering partial and statistical CSI models, and RPA and CCSAA. RPA outperforms CCSAA for the partial CSI model, while CCSAA outperforms RPA for the statistical CSI model even though it has a lower theoretical sum rate guarantee than RPA. We connect this to the different sensitivities of the algorithms to the variation of rates across subchannels for the considered CSI models. We find that the optimal value of K depends on the CSI model, algorithm, and feedback resolution. We also propose a statistical rate upgradation scheme in which the D2D pair exploits the broadcast subchannel allocation information to upgrade its rate. In the last part of our work, we study the subchannel allocation problem with a disjunctivity constraint between the D2D pairs. It prevents two D2D pairs from sharing a subchannel if they cause significant interference to each other. This approach is naturally applicable for dense D2D networks, where D2D pairs are closely spaced and avoids the conservative rate estimates generated by our earlier approaches. We address the subchannel allocation problem for two cases. In the first case, a D2D pair is allowed to transmit on multiple subchannels. We propose a branch-and-bound algorithm to assign subchannels to the D2D pairs. In the second case, a D2D pair is allowed to transmit on only one subchannel. We propose a submodular maximization-based approach in which, for each subchannel, we apply the branch-and-bound algorithm to assign subchannels to the D2D pairs. This approach provides at least half of the optimal D2D sum rate. We look at the disjunctivity constraint and the SINR computation based on path-loss and fading-averaged interference power between the D2D pairs. Our results show that considering fading-averaged interference power that includes the path-loss and shadowing leads to improved system performance than considering only path-loss, which is often considered in the literature.

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Sung, Shao-Chung, and 宋少中. "Multicast with Intra-Cluster Device-to-Device (D2D) Data Sharing Algorithm by Relay Supported Scheme Based on Small World Model." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/r8j2ue.

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碩士
國立交通大學
電信工程研究所
103
Device-to-Device (D2D) communications help improve the performance of wireless multicast service in local area. In this thesis, we propose an improved intra-cluster D2D multicast algorithm to make data sharing realized among D2D users. In our algorithm, the data transmitting order is according to the data demand. In each data transmission process, we will choose a proper transmitter to multicast data in a cluster. Moreover, the relay scheme of data transmission is used in our algorithm, so as to get over transmission rate restriction that made by link quality. Greedy algorithm is used to select transmitter, but we add a parameter to make fairness among all the users. The small world model is concerned in this paper. Simulation shows that the proposed algorithm not only improves the fairness, but also decreases the transmission cost.

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Dissertations / Theses on the topic 'Device-to-device (D2D)'

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