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Дисертації з теми "Multi-Couche de communications":
Boviz, Dora. "Communications multi-utilisateurs dans les réseaux d’accès radio centralisés : architecture, coordination et optimisation." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC035/document.
In future mobile networks denser deployment of radio access points is planned to satisfy demand of higher throughput, but an increased number of mobile users can suffer from inter-cell interference. Fortunately, the centralization of base-band processing offered by Cloud Radio Access Network (C-RAN) architecture enables coordination and joint physical layer processing between cells. To make practical deployment of these techniques possible, we have to study C-RAN in an end-to-end view regarding several aspects: the functional architecture of a deployment, the multi-cell coordination strategy, the implementation of multi-user signal processing and possibilities for optimization to increase operational efficiency.In this thesis, first, we propose an architecture defining the placement of base-band processing functions between the distributed remote units and the central processing unit. The aim of this design is to enable multi-cell processing both on the uplink and the downlink while requiring low data rate between the involved entities. Secondly, we study how low latency coordination can be realized inside the central unit using software defined networking adapted to radio access networks. Our demonstration through a real-time prototype deployment shows the feasibility of the proposed control framework. Finally, we investigate adaptive allocation of fronthaul rate that is used for transferring quantized base-band symbols for users participating in uplink multi-cell reception in order to exploit interference between them. We propose an optimization model that includes the cost of fronthaul tranmissions and aims to maximize the gain of network operators from multi-user transmissions in C-RAN. We solve the optimization problem for different fronthaul pricing models, in a scenario where real-time and accurate channel estimates are available and in another where only channel statistics are exploited. Using our method - fitting in the architecture that we have defined - cost efficiency of fronthaul usage can be significantly improved
Amoordon, Andy. "Méthodes de détection d'attaques cybernétiques par une surveillance multicouches de communication." Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILN042.
Wireless networks are nowadays indispensable components of telecommunication infrastructures. They offer flexibility, mobility and rapid expansion of telecommunication infrastructures. They are also particularly needed to connect mobile devices such as connected cars, watches and drones. Wireless networks are also used in the transport and security sector to connect trains and cameras to monitoring systems. However, in contrary to wired networks in which transmission are isolated in wires, in wireless networks, transmissions are emitted using omnidirectional antennas. This makes wireless networks more vulnerable to unauthorised listening, emission and some specific attacks. In this thesis, we have worked on the detection of three different types of attacks on IEEE 802.11 (Wi-Fi) networks. The three attacks are fake access points and two denial of service attacks namely, deauthentication and jamming attacks. In scientific literature, these three attacks are detected independently and using one or two indicators.We propose a method that uses classification algorithms to create a model that can detect the three attacks by analysing four indicators simultaneously. The model can detect the attacks when they are perpetuated independently and also when they are combined. Concerning data used to create the model, among the three different types of frames that can be transmitted on Wi-Fi networks, we have considered only management frames and more particularly, beacon frames. Beacon frames are sent at regular interval and even in the absence of user traffic. Therefore, basing the detection on the analysis of beacon frames leads to a more efficient detection. In this thesis, we have also considered variations in data rates (absence of user traffic, light, moderate and intense user traffic) and in jamming power (low, moderate and high jamming power). Results show that the model can detect fake access points, deauthentication and jamming attacks (low and moderate power) with high precision. The jamming attack with intense power is detected with satisfying precision. By considering the beacon frames of a farther second access point of the network, we have been able to increase detection precision in the latter case. Finally, we have considered special cases such as Wi-Fi transmissions in the 5 GHz band and the phantom fake access point attack
Nguyen, Le-Duy-Lai. "Contrôle distribué multi-couche des systèmes complexes avec contraintes de communication : application aux systèmes d'irrigation." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT108/document.
This thesis presents control problems of irrigation network with communication constraints and a multi-layer approach to solve these problems in a distributed manner. Detailed discussions of each layer with analytical and simulation results are described throughout several chapters. They emphasize the potential interest of the multi-layer approach, more precisely its efficiency and reliability for supervision, multi-objective optimization and distributed cooperative control of complex water transport systems. Conventionally, the first layer to be considered is the hydraulic network composed of free-surface channels, hydraulic structures and mesh subnetwork of pressurized pipes. By coupling the Saint-Venant equations for describing the physics of free-surface fluid and the Lattice Boltzmann method for the fluid simulation, a discrete-time nonlinear model is obtained for channel reaches. The hydraulic structures are usually treated as internal boundaries of reaches and modeled by algebraic relationships between the flow and pressure variables. To enable the exchange of information among the control system’s components, a communication network is considered in the second layer. Solving challenging problems of heterogeneous devices and communication issues (e.g., network delay, packet loss, energy consumption) is investigated in this thesis by introducing a hybrid network architecture and a dynamic routing design based on Quality of Service (QoS) requirements of control applications. For network routing, a weighted composition of some standard metrics is proposed so that the routing protocol using the composite metric achieves convergence, loop-freeness and path-optimality properties. Through extensive simulation scenarios, different network performance criteria are evaluated. The comparison of simulation results can validate the interest of this composition approach for dynamic routing. Finally, the third layer introduces an optimal reactive control system developed for the regulatory control of large-scale irrigation network under a Distributed Cooperative Model Predictive Control (DCMPC) framework. This part discusses the implementation of different control strategies (e.g., centralized, decentralized, and distributed strategies) and how the cooperative communication among local MPC controllers can be included to improve the performance of the overall system. Managing divergent (or outdated) information exchange among controllers is considered in this thesis as a consensus problem and solved by an asynchronous consensus protocol. This approach based on the multi-agent system paradigm to distributed control requires each controller to agree with its neighbors on some data values needed during action computation. For simulations, a particular benchmark of an irrigation channel is considered. The comparison of simulation results validate the benefits of the distributed cooperative control approach over other control strategies
Aubert, Louis-Marie. "Mise en place d'une couche physique pour les futurs systèmes de radiocommunications hauts débits UWB." Phd thesis, Rennes, INSA, 2005. https://tel.archives-ouvertes.fr/tel-00011745.
The UWB (Ultra Wide Band) consists in transmitting signal between 3. 1 and 10. 6 GHz with a power limited to –41. 3 dBm/MHz. For high data rate (100 to 500 Mbit/s) and short range (1 to 10 m) applications, the state of the art solutions are based on complex digital processing. Mitsubishi ITE proposes an alternative multiband (MB) impulse radio solution based on a non-coherent receiver. The OOK demodulation is done by an original energy detection with a threshold which is adapted dynamically according to propagation conditions. The complete parallelization of this MB-OOK solution allows the system to both avoid inter-symbol interference and recover virtually all available energy. Furthermore the impulsive approach limits multipath channel fading. The comparison of MB-OOK and MB-OFDM systems demonstrates the pertinence of the proposed solution for high data rates and short range applications with low power consumption
Jaber, Chafic. "Modélisation de haut niveau d'abstraction de systèmes intégrés et estimation de performances. Application à une implémentation multi-processeurs de la couche physique d'une station de base LTE." Phd thesis, Télécom ParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-00673731.
Jaber, Chafic. "Modélisation de haut niveau de systèmes intégrés et estimation de performances : application à une implémentation multi-processeurs de la couche physique d’une station de base LTE." Phd thesis, Paris, Télécom ParisTech, 2011. https://pastel.hal.science/pastel-00673731.
The impressive advances in both fields of semiconductors and software engineering enabled modern System-on-Chip “SoC“ to hostcomplex and interdependent applications. These advances are coupled with higher systems complexity and heterogeneity. Thus, forcing designers to re-evaluate their design methodologies and to raise the level of abstraction to the system level targeting the co-design of the entire SoC rather than just individual components. The objective of this Thesis work is to provide the system designer with means (on the methodology and tools levels) to estimate system’s performances and evaluate rapidly and very early the design decisions in the SoC design flow. Our work provides contributions in two main aspects: (1)On the Conceptual Level, we defined (using the UML meta-modeling concepts) modeling concepts to estimate shared resources impact on system’s overall performances, by introducing the “virtual node” concept for scheduling and shared resources access control. Furthermore, we introduced the ”Communication Pattern” concept for modeling the interaction between architecture elements to ensure the orthogonalization of computation and communication concerns. (2)On the Simulation Level: A SystemC simulator was written to simulate the UML models. Simulation is done at a high level of abstraction and runs faster than real time execution. The usability and capabilities of our approach are shown with an industrial use case. We modeled a Freescale multi-core DSP platform for LTE base stations (LTE stands for Long Term Evolution is the 4G standard for cellular networks). The comparison of modeling results with implementation proved the accuracy of our approach
Demeslay, Clément. "Contributions pour le standard IoT LoRa : améliorations du récepteur classique et de sa sécurisation." Electronic Thesis or Diss., Brest, 2023. http://theses-scd.univ-brest.fr/2023/These-2023-MATHSTICBO-Telecommunications-DEMESLAY_Clement.pdf.
This thesis aims to propose enhancements for the LoRa Internet of Things (IoT) standard in order to 1) improve thedemodulation performances in the presence of multi-path channels and 2) develop security mechanisms at the physical layer to strengthen the secrecy of communications.For the first line of contribution, a study of the impact of multi-path channels is conducted and a closed-form expression of the symbol error rate is derived. Capitalizing on this study, the enhanced LoRa RAKE receiver leveraging constructively the paths energy is proposed, for the realistic scenario of channel replicashaving delays close to the main path while taking into account synchronization. For the second line of contribution, the impact of traditional Band and Tone jammers on the LoRa demodulation is investigated and highlights the sub-optimal performances of such jammers. Then, a waveform self-jamming scheme is proposed, considerably reducing demodulation capabilities of interceptors thus further enhancing the secrecy of communications. The induced Peak-to-Average Power Ratio (PAPR) by the scheme is analyzed and a mitigation technique is proposed. Finally, experiments on Software Defined Radio (SDR) equipment are achieved and demonstrate the sustainability of this self-jamming scheme
Berthe, Abdoulaye. "Modélisation et simulation de réseaux locaux et personnels sans fil : intégration des couches PHY et MAC." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1568/.
In this work, we focus on physical and medium access control layer modeling and simulation for short range wireless communication. In particular, the modeling of the Impulse Radio Ultra Wide Band technique for wireless sensor networks and the high data rate communication modeling which uses millimeter wave and beamforming. The first part deals with the modeling of Impulse Radio Ultra Wide Band. The proposed model takes into account the pulse collision induced by multiple concurrent transmissions at the physical layer which is also called multi user interference. This aspect is accurately introduced thanks to the concept of reception time hopping sequences of concurrent reception and their orthogonality. The simulation architecture is built using two models: the first model is based on a uniformly distributed pulse train and the second model, more complete, takes into account variable time hopping sequences. The performance evaluation of this part is based on a typical wireless sensor networks application, in which sensor nodes are scattered on a particular area to detect and report intrusion events to a base station. The second part deals with the modeling of high data rate communication using millimeter wave. The targeted goal of millimeter wave transmission is to increase the data rate using some novel techniques: beamforming and data aggregation. Beamforming is modeled on the so-called codebook beamforming defined as the new beamforming technique for high data rate wireless communication standards. A methodology is developed to take into account the radiation pattern defined by the codebook indexes. For each index the gain of the directional antenna is computed for each direction. This is used in the simulation model physical layer to determine the directional antenna gain in a particular direction during the propagation stage. The defined protocols for sector level and beam level training defined in the 802. 15. 3c draft are also modeled. The performance evaluation of this part is based on a multimedia distribution system
Ben, Slimane Jamila. "Allocation conjointe des canaux de fréquence et des créneaux de temps et routage avec QdS dans les réseaux de capteurs sans fil denses et étendus." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0224/document.
The general context of the present memory is about the cross-layer optimization of wireless sensors networks based on ultra wide band technology UWB. The proposed solutions ensure the share and the efficient allocation of spectral and temporal resources, the optimization of the energy consumption and the support of multi-constraints quality of services QoS. The most challenging issue is providing a tradeoff between the resource efficiency and the multiconstrained QoS support. For this purpose, we proposed a new Wireless Hospital Sensor Network (WHSN) three-tiered architecture in order to support large-scale deployment and to improve the network performance. Then we designed a channel allocation scheme (UWBCAS,)and a prioritized multi-channel multi-time slot MAC protocol (PMCMTP) to enhance network performance and maximize the resource utilization. Finally, we proposed a joint duty cycle scheduling, resource allocation and multi-constrained QoS routing algorithm (JSAR) which simultaneously combines, a duty cycle scheduling scheme for energy saving, a resource allocation scheme for efficient use of frequency channels and time slots, and an heuristic for multi-constrained routing protocol
Ben, Slimane Jamila. "Allocation conjointe des canaux de fréquence et des créneaux de temps et routage avec QdS dans les réseaux de capteurs sans fil denses et étendus." Electronic Thesis or Diss., Université de Lorraine, 2013. http://www.theses.fr/2013LORR0224.
The general context of the present memory is about the cross-layer optimization of wireless sensors networks based on ultra wide band technology UWB. The proposed solutions ensure the share and the efficient allocation of spectral and temporal resources, the optimization of the energy consumption and the support of multi-constraints quality of services QoS. The most challenging issue is providing a tradeoff between the resource efficiency and the multiconstrained QoS support. For this purpose, we proposed a new Wireless Hospital Sensor Network (WHSN) three-tiered architecture in order to support large-scale deployment and to improve the network performance. Then we designed a channel allocation scheme (UWBCAS,)and a prioritized multi-channel multi-time slot MAC protocol (PMCMTP) to enhance network performance and maximize the resource utilization. Finally, we proposed a joint duty cycle scheduling, resource allocation and multi-constrained QoS routing algorithm (JSAR) which simultaneously combines, a duty cycle scheduling scheme for energy saving, a resource allocation scheme for efficient use of frequency channels and time slots, and an heuristic for multi-constrained routing protocol