La congestion des autoroutes est un problème qui apparait de façon récurrente et qui a un large impact économique, environnemental et social. Ce problème peut être résolu en augmentant la capacité des autoroutes ou en diminuant la demande de trafic. Ces solutions sont longues à mettre en oeuvre et sont très coûteuses. Une solution accessible à plus court terme consiste à mettre en oeuvre un système de gestion du trafic. Dans cette optique, plusieurs actions et mesures de contrôle ont été développées pour améliorer l’efficacité des autoroutes. Parmi ces actions, on peut citer le contrôle d’accès et la limitation dynamique de la vitesse. Le contrôle d’accès consiste en une régulation du flux de véhicules désirant entrer sur une autoroute à partir d’une rampe. Nous avons développé la stratégie DFC (Différence de Flux Caractérisée par une densité désirée). Elle vise à maintenir sur la chaussée principale, au niveau de la rampe d’entrée,une densité inférieure à une cible déterminée au préalable à l’aide de simulations. Cette nouvelle stratégie a été comparée aux stratégies existantes telles que ALINEA et PI-ALINEA. La stratégie DFC présente l’intérêt de ne pas générer de phénomènes oscillatoires dans les trajectoires du flux et de ne pas nécessiter de paramètres à régler. La limitation dynamique de la vitesse impose sur plusieurs tronçons de la chaussée principale une limitation de vitesse qui dépend des conditions de circulation. L’objectif est d’éviter la congestion au niveau d’un goulot d’étranglement qui se trouve en aval. Nous avons proposé plusieurs stratégies de limitation dynamique de la vitesse. Elles utilisent toutes le modèle de trafic METANET. Deux des méthodes proposées exploitent le terme d’anticipation du modèle METANET et la troisième est basée sur le flux. Enfin, les différentes stratégies de limitation dynamique de la vitesse ont été utilisées en coordinationavec le contrôle d’accès DFC. La coordination permet d’obtenir des résultats meilleurs qu’un contrôle d’accès utilisé seul ou une limitation dynamique de la vitesse utilisée seule. / The highways congestion is a problem which appears in a recurring way and which has a wide economic, environmental and social impact. This problem can be resolved by increasing the highways capacity or by decreasing the traffic demand. These solutions are long to operate and are very expensive. An accessible solution in the shorter run consists in implementing a traffic management system.In this optics, several actions and control measures were developed to improve the efficiency of highways. Among these actions, we can quote the ramp metering control and the dynamic speed limits.The ramp metering consists of a regulation of the vehicles flow wishing to enter on a highway from an on-ramp. We developed the DFC strategy (Différence de Flux Characterisée par une densité désirée). It aims at maintaining on the main road, at the vicinity of the on-ramp, a density lower than a target beforehand determined by means of simulations. This new strategy was compared with the existing strategies such as ALINEA and PI-ALINEA. The DFC strategy presents the interest not to generate oscillatory phenomena in the trajectories of flow and not to require parameters to be adjusted. The dynamic speed limits imposes on several sections of the main road a speed limit which depends on traffic conditions. The objective is to avoid the congestion at a downstream bottleneck. We proposed several strategies of dynamic speed limits. They use quite the METANET model of traffic. Two of the proposed methods exploit the model METANET anticipation term and the third is based on the flow. Finally, the various strategies of dynamic speed limits were used in coordination with the DFC ramp metering. The coordination allows to obtain the results better than ramp metering used only or dynamic speed limits used only.

Low-power wireless networks consist of spatially distributed, resource-constrained devices – also referred to as nodes – that are typically equipped with integrated or external sensors and actuators. Nodes communicate with each other using wireless transceivers, and thus, relay data – e. g., collected sensor values or commands for actuators – cooperatively through the network. This way, low-power wireless networks can support a plethora of different applications, including, e. g., monitoring the air quality in urban areas or controlling the heating, ventilation and cooling of large buildings. The use of wireless communication in such monitoring and actuating applications allows for a higher flexibility and ease of deployment – and thus, overall lower costs – compared to wired solutions. However, wireless communication is notoriously error-prone. Message losses happen often and unpredictably, making it challenging to support applications requiring both high reliability and low latency. Highly reliable, low-latency communication – along with high energy-efficiency – are, however, key requirements to support several important application scenarios and most notably the open-/closed-loop control functions found in e. g., industry and factory automation applications. Communication protocols that rely on synchronous transmissions have been shown to be able to overcome this limitation. These protocols depart from traditional single-link transmissions and do not attempt to avoid concurrent transmissions from different nodes to prevent collisions. On the contrary, they make nodes send the same message at the same time over several paths. Phenomena like constructive interference and capture then ensure that messages are received correctly with high probability. While many approaches relying on synchronous transmissions have been presented in the literature, two important aspects received only little consideration: (i) reliable operation in harsh environments and (ii) support for event-based data traffic. This thesis addresses these two open challenges and proposes novel communication protocols to overcome them.