9 research outputs found
ContrÎle de charge des réseaux IoT : D'une étude théorique à une implantation réelle
Prenons en exemple une salle de classe composĂ©e dâun professeur et de nombreux Ă©lĂšves, lorsque trop dâĂ©lĂšves sâadressent en mĂȘme temps au professeur ce dernier nâest plus en mesure de comprendre les paroles transmisses par les Ă©lĂšves. Cette illustration sâĂ©tend Ă©videmment aux systĂšmes de communications sans fil (la 4G par exemple). Dans ces systĂšmes, les terminaux (les Ă©lĂšves par analogie) transmettent sur un canal, nommĂ© canal en accĂšs alĂ©atoire, des messages qui sont potentiellement rĂ©ceptionnĂ©s par la station de base (le professeur par analogie). Ces canaux ne sont habituellement pas surchargĂ©s car leur capacitĂ© (nombre de messages reçus par seconde) est tellement importante quâil est trĂšs complexe de surcharger le canal. LâĂ©mergence de lâInternet des objets oĂč des milliards de petits objets devraient ĂȘtre dĂ©ployĂ©s partout dans le monde a changĂ© la donne. Ătant donnĂ© leur nombre et leur type de trafic, ces derniers peuvent surcharger les canaux en accĂšs alĂ©atoire. Ainsi, le sujet : « contrĂŽle de charge des canaux en accĂšs alĂ©atoire » a connu un gain dâintĂ©rĂȘts ces derniĂšres annĂ©es. Dans cette thĂšse nous avons dĂ©veloppĂ© des algorithmes de contrĂŽle de charge permettant dâĂ©viter quâune station de base soit surchargĂ©e. Cela est trĂšs utile pour les opĂ©rateurs TĂ©lĂ©coms, ils sont dĂ©sormais certains quâil y nây aura pas de perte de service Ă cause de ces surcharges. Tous les principes dĂ©veloppĂ©s dans cette thĂšse seront intĂ©grĂ©s dans un futur proche aux produits IoT dâAirbus
Adaptive load control for IoT based on satellite communications
The Internet Of Things (IoT) market is growing more and more every year. Today, the number of IoT devices is estimated around 8 billion but forecasts announce 20 billion devices for 2020. Terrestrial or satellite communications systems are already deployed to answer the connectivity need. These systems rely on a Random Access CHannel (RACH) used either to send resource allocation requests or directly the useful message. Because of the number of IoT devices, the overload on the RACH is an emerging issue since it may cause a service outage. This is especially the case for IoT satellite systems because of the wide area covered by a single satellite. The Access Class Barring (ACB) is the load control mechanism used within the Narrow Band IoT. Unfortunately, no method was specified to compute the load control parameters. In this paper, in the context of a satellite IoT system, we propose a method to compute dynamically ACB based load control parameters. Thanks to our method, the load control mechanism reach excellent results regarding transmission reliability and energy consumption for various traffic scenarios
IoT networks load control mechanisms : From a theoretical study to a real implementation
Prenons en exemple une salle de classe composĂ©e dâun professeur et de nombreux Ă©lĂšves, lorsque trop dâĂ©lĂšves sâadressent en mĂȘme temps au professeur ce dernier nâest plus en mesure de comprendre les paroles transmisses par les Ă©lĂšves. Cette illustration sâĂ©tend Ă©videmment aux systĂšmes de communications sans fil (la 4G par exemple). Dans ces systĂšmes, les terminaux (les Ă©lĂšves par analogie) transmettent sur un canal, nommĂ© canal en accĂšs alĂ©atoire, des messages qui sont potentiellement rĂ©ceptionnĂ©s par la station de base (le professeur par analogie). Ces canaux ne sont habituellement pas surchargĂ©s car leur capacitĂ© (nombre de messages reçus par seconde) est tellement importante quâil est trĂšs complexe de surcharger le canal. LâĂ©mergence de lâInternet des objets oĂč des milliards de petits objets devraient ĂȘtre dĂ©ployĂ©s partout dans le monde a changĂ© la donne. Ătant donnĂ© leur nombre et leur type de trafic, ces derniers peuvent surcharger les canaux en accĂšs alĂ©atoire. Ainsi, le sujet : « contrĂŽle de charge des canaux en accĂšs alĂ©atoire » a connu un gain dâintĂ©rĂȘts ces derniĂšres annĂ©es. Dans cette thĂšse nous avons dĂ©veloppĂ© des algorithmes de contrĂŽle de charge permettant dâĂ©viter quâune station de base soit surchargĂ©e. Cela est trĂšs utile pour les opĂ©rateurs TĂ©lĂ©coms, ils sont dĂ©sormais certains quâil y nây aura pas de perte de service Ă cause de ces surcharges. Tous les principes dĂ©veloppĂ©s dans cette thĂšse seront intĂ©grĂ©s dans un futur proche aux produits IoT dâAirbus.Take for example a classroom composed of a teacher and many students. When too many students address at the same time to the teacher, the latter is no longer able to understand the words transmitted by students. This illustration obviously extends to wireless communication systems (the 4G for example). In these systems, terminals (students by analogy) transmit on a channel, named random access channel, messages that are potentially received by the base station (the teacher by analogy). These channels are usually not overloaded because their capacity (number of messages received per second) is so important that it is very complex to overload the channel. The emergence of the Internet of Things, where billions of small objects should be deployed around the world, has changed the game. Due to their number and type of traffic, they can overload random access channels. Therefore, the subject: "load control of random access channels" has seen an increase in interest in recent years. In this PhD we have developed load control algorithms to prevent a base station from being overloaded. This is very useful for telecom operators, they are now certain that there will be no loss of service because of these overloads. All the principles developed in this thesis will be integrated in the near future within Airbus IoT product
Modelling Discontinuous LEO Satellite Constellations: Impact on the Machine-To-Machine Traffic and Performance Evaluation
International audienceDiscontinuous LEO satellite constellations (DisLEO) are expected to be more and more exploited in future satellite telecommunication systems especially in the context of delay-tolerant networks such as messaging and Machine-To-Machine (M2M) communications. No modelling for this type of constellation has been proposed yet. We highlight two different studies points of view: satellite and ground. In this paper, we analyse widely the satellite point of view and we define a new traffic modelling for M2M communications at the satellite point of view. Because of the satellite discontinuity, classical traffic modelling for terrestrial or satellite networks are inadequate. This paper explains the generation of new terminals (who has new message to transmit) under the satellite coverage. To illustrate how works the new traffic model, we perform an example of protocols performance evaluation
LGBTQIA+ International Students and Socioemotional Well-Being: Impact of Intersectionality on Perceived Experiences and Campus Engagement
International students are more likely to experience mental health issues and increased stress. Mental health is often surrounded by negative societal stigmas that act as barriers to seeking support and tend to lead to greater mental health concerns. International students tend to seek socioemotional support from other international student peers rather than seeking out counseling services. However, this study shows that LGBTQIA+ international students were less likely to seek socioemotional support from other international student peers due to fear of their sexual orientation being discovered and their families finding out about their identity. This study examines how LGBTQIA+ international students talk about their experiences on and off campus in relations to their socioemotional well-being. Specifically, this study sought to better understand the complexities of LGBTQIA+ studentsâ identities, and the challenges they faced in terms of their socioemotional well-being. Implications for practice and future research are discussed
The EUREC4A-Ocean/Atmosphere campaign: status
International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation
The EUREC4A-Ocean/Atmosphere campaign: status
International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation
The EUREC4A-Ocean/Atmosphere campaign: status
International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation
The EUREC4A-Ocean/Atmosphere campaign: status
International audienceThe ocean fine scale (from the mesoscale to the submesoscale) is susceptible to impact air-sea exchange and has an integral effect on the large scale atmosphere and ocean dynamics. Many recent advances in understanding underlying processes have been obtained from modeling efforts and only few in-situ observational studies exist one of them being the EUREC4A-OA/ATOMIC campaign that was added to the EUREC4A atmospheric campaign. This experiment took place in January-February 2020 in the Northwest Tropical Atlantic Ocean with the aim to collect synchronized ocean and atmosphere data to improve our understanding of the role of fine scale processes in the internal ocean dynamics and air-sea interaction.Four oceanographic vessels, coordinated with air-borne observations and autonomous ocean platforms (underwater gliders, Saildrones, drifters), simultaneously acquired ocean and atmosphere data east of the island of Barbados and further south, up to the border of French Giuana. This way, ocean and atmospheric data was acquired in two contrasting regions: (1) the Trade wind region and (2) a region filled with mesoscale eddies. Operations allowed investigating upper ocean processes from small to mesoscale and from sub-diurnal to monthly.A variety of mesoscale eddies were crossed with diverse characteristics, ranging from shallow cyclonic and anticyclonic eddies to the deep reaching structures. Some of these eddies, and in particular North Brazil Rings, have been previously observed and described in dedicated oceanographic experiments. Nonetheless, the EUREC4A-OA/ATOMIC campaign brings in new details about the vertical structure, the dynamics and the potential impact on air-sea interactions of these mesoscale features.With the various observing platforms it was possible to sample the upper-ocean in great detail, resolving frontal scales and stratification. For example, the remnants of the Amazon plume, flowing northward along the shelf-break and being advected far offshore though NBC rings, create a rich variety of submesoscale fronts and a strong barrier layer impacting air-sea exchange of heat and momentum. The ongoing analyses on the ocean dynamics regional and local structures and specifics of air-sea interaction will be highlighted in this presentation