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International audience; In this paper we aim at introducing Unmanned Aerial Vehicles (UAVs) to prevent accidents, considering a use case that is likely to happen in cities where vehicles are circulating and when approaching an intersection like a pedestrian crossing, a railway crossing or a crossroad. A first UAV observes from the top of the scene and will, in certain cases, notify a second UAV which will exchange information either with the car driver if its behavior is far from a reference profile, or with the infrastructure in the ultimate case. We highlight interactions between the two UAVs (U2U communication) as well as between the UAV and the car vehicle (U2V communication) and between the UAV and infrastructure (U2I communication). Hence, we emphasize the benefit of using UAVs to enhance safety and reduce accident gravity rate.

This paper proposes an improved model for the nonlinear behavior of the components of Radio-over-Fiber (RoF) links focusing here on the laser source. In a previous work, it was shown with a flexible new opto-microwave design approach a first behavioral model of RoF links that exploited the hyperbolic tangent function (the so-called tanh model) to model the highpower nonlinearities. Since this was not sufficient to simulate adequately all the nonlinearities, in this work, for the first time in the authors’ knowledge, the improved nonlinear model based on Cann’s model is developed, on an electro optic transducer. Then the amplitude-to-amplitude conversion of the link is better taken into account with the introducing of nonlinear properties of the link at high input power in the model. The new transfer equation includes several parameters that can be adjusted to adapt the model to any of the components, especially the photo-emitters under study, which are the main cause of this type of nonlinear behavior of the system. In particular, this improved model is applied on the state-of-the-art 850 nm GaAs Vertical Cavity Surface Emitting Laser (VCSEL), simulating several Figures of Merit such as the Error-Vector Magnitude (EVM) of a Long Term Evolution (LTE) signal with a Quadrature Phase Shift Keying (QPSK)and the output amplitude-modulated power versus input amplitude-modulated power, also called AM/AM curve. This new proposed nonlinear model outperforms other existing behavioral models and its non linear simulation better fits with the measurements. Finally, we conclude that the performance improvement highly depends on the nonlinearity sharpness parameter, depending on the frequency and the bias current.

International audience; The characteristic pillars of a city are its economy, its mobility, its environment, its inhabitants, its way of life, and its organization. Since 1980, the concept of smart city generally consists of optimizing costs, organization, and the well-being of inhabitants. The idea is to develop means and solutions capable of meeting the needs of the population, while preserving resources and the environment. Owing to their little size, their flexibility, and their low cost, Unmanned Aerial Vehicles (UAV) are today used in a huge number of daily life applications. UAV use cases can be classified into three categories: data covering (like surveillance and event covering), data relaying (like delivery and emergency services), and data dissemination (like cartography and precise agriculture). In addition, the interest to Cooperative Intelligent Transportation Systems (C-ITS) has risen in these recent years, especially in the context of smart cities. In such systems, both drivers and traffic managers share the information and cooperate to coordinate their actions to ensure safety, traffic efficiency, and environment preservation. In this work, we aimed at introducing a UAV in a use case that is likely to happen in C-ITS. A conflict is considered involving a car and a pedestrian. A UAV observes from the top of the scene and will play the role of the situation controller, the information collector, and the assignment of the instructions to the car driver in case of a harmful situation to avoid car-pedestrian collision. To this end, we highlight interactions between the UAV and the car vehicle (U2V communication), as well as between the UAV and infrastructure (U2I communication). Hence, the benefit of using UAV is emphasized to reduce accident gravity rate, braking distance, energy consumption, and occasional visibility reduction.

International audience; In this paper, we develop a generic approach to determine the best technology to carry the communication between an Unmanned Aerial Vehicle (UAV) and a ground control station (GCS). For this, we consider that the UAV is performing its task under nominal conditions. Based on related work, we select the most relevant criteria of interest. Then, we compare technologies performances in the 2.4 GHz and 5.8 GHz ISM bands, using a multi-criteria analysis. Technology assessment results depend on the use-case and the UAV scenario. In this work, we are focused on the precise agriculture (PA) use-case, and we present the assessment results in both Visual Line of Sight (VLOS), Extended Visual Line of Sight (EVLOS), as well as Beyond Line of Sight (BVLOS) scenarios. The latter is very interesting because the communication UAV-GCS becomes of critical importance.

International audience; In this paper, we develop an analytic methodology to determine the best technology to carry the communication between an Unmanned Aerial Vehicle (UAV) and a ground control station (GCS). We assume herein that the UAV is performing its mission under nominal conditions. For this, we identify some relevant criteria that cover most use-cases. We propose a multi-criteria analysis to determine the best technology to carry the radio-communication between the UAV and the GCS. In this work, we distinguish between the Control and Non-Payload Communication Channel (CNPC) and the Payload Channel. By studying two different missions, we emphasize that the technology assessment results depend on the use-case as well as the UAV scenario, and that for a same scenario the results for CNPC are different from the Payload communication. In this work, we are focused on the precise agriculture (PA) use-case, and the public safety (PS) use case. We present the assessment results in both Visual Line of Sight (VLOS), and Beyond Line of Sight (BVLOS) scenarios. The latter is very interesting because the communication UAV-GCS becomes of critical importance.

Nowadays, conventional learning methods where students are often passive or forced to work show more and more their limits, especially with the advent of the Internet, tablets and smartphones… Therefore, looking for alternative methods is required. In this work, we present three new methods of teaching that seem promising for engineering students: online tutoring, playing games and interdisciplinary projects. We propose to combine them in a new inter-semestrial course for engineering students, at the middle of their curriculum, and through an example focused on the Internet of Things.

International audience; We present in this survey new technologies proposed for the evolution of the aeronautical communication infrastructure. Motivated by studies that estimate the growth of air traffic flow, it was decided to develop a future communication infrastructure (FCI) adapted to the future aeronautical scenario. The FCI development involves researchers, industrials, and aeronautical authorities from many countries around the world, and started in 2004. The L-band Digital Aeronautical Communication System (L-DACS) is the part of the FCI that will be in charge of continental communication. The L-DACS is being developed in Europe since 2007 and two candidates were preselected: L-DACS1 and L-DACS2. In this paper, we first describe the motivations of the FCI. We then give an overview of its development activities from 2004 to 2009. After that, we provide some insights about both preselected L-DACS candidates, at their physical and medium access layers. Finally, we address the challenges on the development of the FCI/L-DACS.

International audience; In the last decade, the aeronautical authorities ex- pressed their need to develop a new system for aeronautical radio- communications. The L-band Digital Aeronautical Communica- tion System (L-DACS) is the part of the future system that will be operating in a part of the aeronautical L-band (960−1164 MHz), already occupied by a large number of radio-frequency legacy systems. This paper aims at studying the L-DACS impact on a legacy system, the Distance Measuring Equipment (DME), under two critical situations. Such topics are fundamental in aeronau- tics, as any communication or radionavigation dysfunction may endanger flight and passengers security. Some obtained results will be used for the L-DACS standardization and its specifications finalization. For the first scenario (air-to-air scenario), we propose a deterministic algorithm to compute the interference level in the frequency domain. Since this seems to be insufficient for the second scenario (co-site scenario), we develop a time-frequency approach to analyze the interference using an aeronautical RFC test-bed that we implemented at Supelec.

International audience; Interference between radio systems may occur if they share the same environment and use close frequencies at the same time. To ensure their successful coexistence, the Electro- magnetic Compatibility (EMC) established rules and regulations within standardisation bodies and aims to protect these systems from harmful interference. Nowadays, with the proliferation of wireless communications and digital technologies, in addition to electronics evolution inside radio terminals, some additional parameters and new techniques are needed to represent more accurately the interference environment and guarantee radio systems coexistence. In this work, we provide an overview of the main standards related to EMC approaches and measure- ment techniques currently in use, and we show the benefits of considering time-domain parameters in the EMC analysis.

In this paper, we consider the Radio-Frequency Compatibility (RFC) of a candidate system within future aeronautical communication infrastructure, being developed since 2004 to accommodate the evolution of the aeronautical environment. The system presented in this paper is one of the two preselected proposals for the L-band Digital Aeronautical Communication System (L-DACS), in charge of the continental communications. It is named L-DACS2 and will use the 960 to 1164 MHz band, allocated to the Aeronautical Mobile Service reserved for communications relating to safety and regularity of flight. This band is characterized by a very dense spectral occupation by a large number of aeronautical systems. The RFC (branch of electrical science that studies the coexistence of radio systems in the same electromagnetic environment) is very important for L-DACS deployment and if it is not satisfied, the flight safety could be endangered. We propose to study in this paper the impact of the LDACS2 on the Distance Measuring Equipment (DME), which has been using the L-band for decades. According to recent studies performed in the frequency domain (continuous transmissions and no time domain variations), the achieved RFC level seems insufficient. The objective of this work is to analyze the RFC between LDACS2 and DME considering the time domain aspects of both systems. The idea is to quantify the impact of the radio-frequency signals generated by L-DACS2 interferer (transmitter) on the performance of a DME victim (receiver). The study is performed for the co-site case (equipments onboard of the same aircraft). To study the RFC between the two systems, we investigate various modulations for the future communication system. The results are obtained through computer simulations and laboratory measurements with an aeronautical test-bed using a commercial DME unit. The DME performance degradation is evaluated for some values of the Signal to Interference Ratio.

In this paper, we consider the Radio-Frequency Compatibility (RFC) of a candidate system for the future aeronautical communication infrastructure. This infrastructure is being developed within the International Civil Aviation Organization since 2004, to accommodate the air traffic load and improve the aerial security. The system presented in this paper is one of the two preselected proposals for the L-band Digital Aeronautical Communication System (L-DACS), which will be responsible for the continental communications. This proposed candidate is named L-DACS2 and is foreseen to use part of the L-band spectrum (960 to 1164 MHz) allocated to the Aeronautical Mobile Service reserved for communications relating to safety and regularity of flight. Despite its potentially large spectrum, the L-band is a challenging environment for aeronautical communications because of the channel propagation characteristics and the dense spectral occupation by a large number of aeronautical systems. On the other hand, the RFC characterizes the electromagnetic compatibility between two radio systems and determines if they can coexist in the same electromagnetic environment. For this reason, the RFC is one of the main issues for L-DACS deployment and if it is not satisfied, the flight safety could be endangered. Hence, we propose to study in this paper the impact of the L-DACS on the Distance Measuring Equipment (DME), which is a very important equipment that has been using this band for decades. According to recent studies performed in the frequency domain , that is assuming continuous transmissions and no time domain variations, the achieved RFC level seems insufficient. The main objective of this work is to analyze the RFC between L-DACS2 and DME taking into account the time domain aspects of both systems. The idea is to verify and quantify the impact of the radio- frequency signals generated by a L-DACS2 interferer on the performance of a DME victim receiver. The study is performed for the co-site case (\emph{i.e.} when both equipments are onboard of the same airplane), which is the most critical interference scenario due to the proximity of both systems. The results are obtained through computer simulations as well as laboratory measurements. They present the DME performance degradation for some values of the Signal to Interference Ratio, assuming a constant DME signal level and different L-DACS2 interference powers.

The aeronautical community has recently decided to develop a new digital aeronautical communication system, named L-DACS, in order to fulfill the new air traffic requirements. This system, which will operate in the L frequency band (960 to 1164 MHz), would be internationally deployed from 2020. Many technologies were considered for this new aeronautical system but only two among them were preselected by the International Civil Aviation Organization (ICAO): candidate one, named L-DACS1, is based on a FDD-OFDM technology and candidate two, named L-DACS2, is based on a TDD-GMSK technology. One of the most important issues for both candidates is the electromagnetic compatibility (EMC) with the legacy systems operating in the same band or/and in adjacent bands. Different scenarios have to be evaluated due to the fact that these systems will be implanted either in the airplanes (on board) or in ground stations. In this paper, we propose to evaluate the air-air scenario, where we focus on the signals generated by onboard L-DACS transmitters on onboard victim receivers, taking into account the L-DACS antenna radiation pattern and the frequency mask. The study emphasizes that the interference phenomenon can be one of the main limitations for the L-DACS development.

General and commercial aviation authorities have been using amplitude modulation communication systems for more than 70 years. Due to the great increase of air traffic during the last years, the VHF band tends towards saturation, whereas the aeronautical community faces new requirements: data rate, spectral efficiency and network capacity (maximum number of aircrafts simultaneously connected). Recently, the development of a new digital aeronautical communication system, named L-DACS, was proposed. This system will operate in the L band part allocated to aeronautics. There were many proposals but only two candidates have been pre-selected by the ITU and ICAO for this future communication system: L-DACS1 and L-DACS2. The deployment of this new system is expected to start after 2020. Among other issues, one important aspect is the impact of L-DACS on legacy systems. Actually, there are many onboard systems operating in L band, and any disfunction can put in danger the flight safety. This paper studies the maximum interference level generated by the two L-DACS candidates on a generic onboard receiver. Taking into account the antenna radiation pattern and the specific transmission mask of both candidates, the study determines the worst interference level and the corresponding spatial positions of the aircrafts around the receiver. The results show that the interference level can be determined by considering the several nearest aircrafts to the victim.