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A stochastic model is introduced that accurately models collisions in Flying Ad Hoc wireless Networks (FANETs) where Unmanned Aerial Vehicles (UAVs) are flying within the same shared 3D airspace. The model has two input parameters, the number of flying UAVs and the average time for an arbitrary UAV to come into contact with another UAV (the inter contact time). Using only these two parameters, we provide simple, yet accurate closed-form expressions for different collision related metrics such as safety periods, survival probabilities and number of collisions. Two scenarios are particularly considered. The first assumes that UAVs are equipped with perfect collision detection and avoidance capabilities. This is essentially to answer the question of whether detection and resolution tools are required for a given UAVs fleet to accomplish its mission. The second scenario assumes that small UAVs cannot satisfy the requirements of collision detection and avoidance equipage due to their size, weight or power constraints. While the number of deployed UAVs is easily known, the setup of the inter contact time is rather problematic for the end user (space controller) of the system. To this end, we developed a generic simple expression of the inter contact time to ease the administration task. This generic expression is then instantiated to two mobility models. Extensive simulations based on OMNeT++ are used to validate the obtained analytical results. The simulation results are shown to be in a remarkable agreement with those of the conducted mathematical analysis.

International audience; The Internet of Things (IoT) ecosystem includes a plethora of devices equipped with heterogeneous communication interfaces. They exhibit different mobility patterns and hardware constraints as memory, battery and processing power. On the other hand, IoT applications are overlayed on top of these constrained-devices imposing stringent requirements in term of data availability, data coherence, and response latency. To cope with these challenges, Named Data Networking (NDN) architecture is positioned in the middle layer to act as the networking layer. By providing easy data access thanks to the unique and location-independent content names, in-network caching and name-based routing, NDN expects to hide from IoT applications the complexity and diversity of the underlying Things by adapting the network operation to their features. In this paper, we focus on data availability requirements threatened by high IoT network dynamics related to sensors mobility. We address the producer mobility issue in NDN/IoT networks using the routing-based approach. We propose a novel and efficient forwarding algorithm named AFIRM in order to support producer mobility, and compare its performances to those of other relevant solutions based on the routing approach.

Conflict detection is an important research issue in Unmanned Aerial Vehicles to ensure safety and collision free flights. In this paper, we first propose a comprehensive analytical framework for a three dimensional conflict detection. Then, we propose SLIDE a new Straight LIne conflict DEtection and alerting algorithm for a set of UAVs to safely share a common airspace. SLIDE is fully distributed and requires a limited state information exchange between UAVs. The assumptions of precise state information and packet-loss free communications are relaxed so as to guarantee the applicability and efficiency of the algorithm in real world situations. A thorough discussion is also presented to deal with appropriate tuning of the different parameters of the collision detection framework. Extensive simulations based on OMNeT++ are used to validate SLIDE and evaluate its performance. Simulation results indicate that SLIDE guarantees a reduced number of false and missed alarms even in high density traffic scenarios and communication perturbed environments, yet it leaves adequate time to accomplish the required maneuver actions.

The Internet of things (IoT) is commonly perceived as the mere extension of the current Internet to our physical world to interconnect an unprecedented number of sensors/actuators, referred to as things. In this Internet architectural context, some IoT services are currently offered by several Telecom operators of the Arab World such as tracking services, near field communication, and surveillance, e-health and security services. However, the current Internet TCP/IP protocol suite has reached its limits and is deemed inappropriate to deal with the stringent challenges imposed by the heterogeneity as well as the number of these constrained devices. On the other hand, the Named Data Networking (NDN) has recently received a lot of attention as a potential Information-Centric Networking (ICN) architecture for the future Internet. The NDN paradigm, relying on location-independent naming, in-network caching, name-based routing, multicast, anycast, mobility and self-secured content, has a great potential to efficiently address and solve the current seminal IP-based IoT architecture issues and requirements. In this paper, we first overview the current research and development progress in ICN, then we conduct a comparative study of the relevant ICN proposals and platforms, and finally, we discuss the suitability of the NDN as a promising lever architecture for IoT.

The presence of communication obstructing entities severely degrades the routing efficiency in Mobile Ad hoc Networks (MANET). While several routing protocols have proposed ways to mitigate this degradation essentially by getting around and avoiding obstacles, the detection of obstacle locations and their contours driven by the very signaling of the underlying routing protocol has not been given that much attention. Yet, the integration of such a capability within the routing protocol presents an adequate leverage of the routing efficiency. In this paper, we first propose a distributed autonomic scheme to locate obstructing entities (coined ALOE) within a MANET using the basic signaling of the Cartography Enhanced Optimized Link State routing (CE-OLSR) protocol. Then, we propose ALOE-CE-OLSR the integration of ALOE within CE-OLSR, and show the resulting improvement in routing validity as compared to that of both CE-OLSR with and without a priori knowledge of the obstructing entities map. While the routing validity measures the pertinence of the routes computed by the underlying routing protocol, two new metrics, namely the coverage and the precision ratios, are defined to properly evaluate the efficiency and performance of our proposed detection scheme, in addition to the throughput as well as the end-to-end delay of received data packets. Simulation results show that our proposed CE-OLSR signaling-based obstacle detection scheme accurately localizes and detects the boundaries of the stationary obstructing obstacles. The integrated ALOE-CE-OLSR achieves the same route validity, throughput and delay as CE-OLSR with a priori precise knowledge of the obstacles map.

International audience; The Information-Centric Networking (ICN) paradigm is shaping the foreseen future Internet architecture by focusing on the data itself rather than its hosting location. It is a shift from a host-centric communication model to a content-centric model supporting among others unique and location-independent content names, in-network caching and name-based routing. By leveraging the easy data access, and reducing both the retrieval delay and the load on the data producer, the ICN can be a viable framework to support the Internet of Things (IoT), interconnecting billions of heterogeneous constrained objects. Among several ICN architectures, the Named Data Networking (NDN) is considered as a suitable ICN architecture for IoT systems. However, its default caching approach lacks a data freshness mechanism, while IoT data are transient and frequently updated by the producer which imposes stringent requirements in terms of information freshness. Furthermore, IoT devices are usually resource-constrained with harsh limitations on energy, memory and processing power. We propose in this paper a caching strategy and a novel cache freshness mechanism to monitor the validity of cached contents in an IoT environment while minimizing the caching process cost. We compared our solution to several relevant schemes using the ccnSim simulator. Our solution exhibits the best system performances in terms of hop reduction ratio, server hit reduction ratio and response latency, yet it provides the lowest cache cost and significantly improves the content validity.

Named-Data Networking (NDN) is a promising candidate for the Internet of Things (IoT) which targets to improve data dissemination efficiency. This new paradigm brings considerable benefits such as minimizing the content producer solicitation and rapid data transmission. However, the producer mobility issue in NDN is not sufficiently addressed. Especially, in IoT scenario, in which devices are frequently mobile and it requires data to keep continuity. In this paper, we present proposed producer mobility solutions in NDN in an IoT context.

International audience; In-network caching in Named Data Networking (NDN) based Internet of Things (IoT) plays a central role for efficient data dissemination. Data cached throughout the network may quickly become obsolete as they are transient and frequently updated by their producers. As such, NDN-based IoT networks impose stringent requirement in terms of data freshness. While various cache replacement policies were proposed, none has considered the cache freshness requirement. In this paper, we introduce a novel cache replacement policy called Least Fresh First (LFF) integrating the cache freshness requirement. LFF evicts invalid cached contents based on time series forecasting of sensors future events. Extensive simulations are performed to evaluate the performance of LFF and to compare it to the different well-known cache replacement policies in ICN-based IoT networks. The obtained results show that LFF significantly improves data freshness compared to other policies, while enhancing the server hit reduction ratio, the hop reduction ratio and the response latency.

International audience; Information-Centric Networking (ICN) is an emerging network paradigm based on name-identified data objects and in-network caching. Therefore, ICN contents are distributed in a scalable and cost-efficient manner. With the rapid growth of IoT traffic, ICN is intended to be a suitable architecture to support IoT networks. In fact, ICN provides unique persistent naming, in-network caching and multicast communications which reduce the data producer load and the response latency. Using ICN in an IoT environment requires a study of caching policies in terms of cache placement strategies and cache replacement policies. To this end, we address, in this paper, caching challenges with the aim to identify which caching policies are suitable for IoT networks. Simulation findings show that the combination of the consumer-cache caching strategy and the RR cache replacement policy is the most convenient in IoT environments in terms of hop reduction ratio, server hit reduction and response latency.

International audience; The Internet of Things (IoT) is a way to address and communicate with objects and their virtual representations. The exponential development of Smartphone, tablet, sensors and their applications has created very complex systems. From here, the concept of M2M (Machine-to-Machine) has emerged to provide communication and service architecture without human intervention. The European Telecommunications Standards Institute (ETSI) has proposed a horizontal architecture that can fit to several domains: transport, energy, e-health, etc. A crucial aspect is the management of devices in a system where equipment can be used during decades. Several protocols exist, in this article we explain the OMA DM management protocol, and we describe its connection to the ETSI-M2M platform. An extension of device management is proposed with an autonomic capability.

The legacy power grid has several limitations resulting in misuse and mismanagement of energy. The evolution of IT technologies have empowered revolutionizing the power grid and created the concept of the Smart Grid. Hence, the Smart Grid is considered as the integration of the latest information, communication and operational technologies with the traditional power grid in order to enhance energy management within a reliable, efficient network linking the diffirent grid actors from the consumer to the end-head system such as energy providers and billing services. Introducing new technologies into Smart Grid raises new issues, mainly security issues. Therefore, in this paper, after presenting the Smart Grid and the smart metering system, we present the security requirements of the Smart Grid and we highlight the user privacy concern as well as the different techniques proposed in literature to deal with it. Our main objective is to provide a study of the existing techniques preventing privacy disclosure.

In a previous work, we build an M2 M overlay network over the Internet in order to ensure private communication between M2 M devices, M2 M gateway and M2 M applications. We propose in this paper to add the autonomic man- agement of this overlay network. We add the self-healing and self-optimization capabilities to the M2 M gateway. The M2 M gateway is able to detect failures in the overlay path and recover from them. It is also able to dynamically monitor the overlay path and select the best available path in term of RTT. These two features are provided by the reachabil- ity protocol (REAP) at the gateway level. We implement our solution on the OMNeT++ network simulator. Results highlight the novel gateway capabilities: it recovers from failures and always select the best available path.

In Vehicular Ad-hoc Networks (VANETs), any vehicle uses a location service to get an up-To-date data of all vehicles' positions in its vicinity. Many location services rely on infrastructures to perform location update and location query tasks. However, the infrastructure penetration rate may differ from one region to another. We propose in this paper a new location service called Vehicle-Aided Location Service in urban environment (VALS) which resolves the problem of the shortage of infrastructure in some city districts. VALS replaces the missing Road-Side Units (RSU) with vehicles offering RSUs functionalities. It is based on a hierarchical and cluster-based design. Simulation results show that VALS achieves a high success ratio (86%), get most vehicles' data (82%) and a good position information level accuracy (less than 20 m) with a low RSU penetration rate (40%). 2016 IEEE. Scopus

International audience; Sensing coverage is a fundamental issue for Wireless Sensor Networks (WSNs). Several coverage configuration protocols have been developed; most of them presume the availability of precise knowledge about each node location via GPS receivers. However, equipping each sensor node with a GPS is very expensive in terms of both energy and cost. On the other hand, several GPS-less localization algorithms that aim at obtaining nodes locations with a low cost have been proposed. Although their deep correlation, sensing coverage and localization have long been treated separately. In this paper, we analyze, design and evaluate a novel integrated framework providing both localization and coverage guarantees for WSNs. We integrate the well-known Coverage Configuration Protocol CCP with an improved version of the localization algorithm AT-Dist. We enhanced the original specification of AT-Dist in order to guarantee the necessary localization accuracy required by CCP. In our proposed framework, a few number of nodes are assumed to know their exact positions and dynamically vary their transmission ranges. The remaining sensors positions are derived, as accurately as possible, using this little initial location information. All nodes positions (exact and derived) are then used as an input for the coverage module. Extensive simulation results show that, even with a very low anchor density, our proposal reaches the same performance and efficiency as the ideal CCP based on complete and precise knowledge of sensors coordinates. A preliminary version of this paper appeared in ANT 2014, June 2-5, Hasselt, Belgium. This version includes a concrete enhancement of the original specification of AT-Dist in order to guarantee the necessary localization accuracy required by CCP. Furthermore, we allowed anchors to vary their transmission ranges. Extensive simulations results are included to ascertain the performance of the integrated system.

Today, we are witnessing the dawn of the era of Internet of Things (IoT) where trillions of physical objects are expected to come online and communicate. Cisco goes even further by introducing the concept of Internet of Everything (IoE), which refers to people-to-people, machine-to-people and machine-to-machine communications.

International audience; Graph coloring was exploited in wireless sensor networks to solve many optimization problems, mainly related to channel assignment. In this paper, we propose to use coloring to jointly manage channel access and routing to the sink. We introduce CHRA, a coloring based hierarchical routing approach. Coloring is exploited to avoid interferences and also to schedule nodes transmissions to the sink. We provide an analytical study assessing the performance of CHRA and present an investigation of various coloring heuristics to study their impact on CHRA performances on maintaining the network connectivity and coverage, while reducing the energy consumption.

Host and network mobility support mechanisms aim to provide a seamless access to Internet while end users are changing their point of attachment. When a mobile entity roams from a network to another, a handover occurs causing communication session discontinuity degrading real-time application performance. Assuming that such inconvenience is a congestion, TCP recovery is slow and careful. We have previously proposed a cooperation between TCP and MIPv6 and proved its efficiency through OMNeT++ simulations. In this paper, We study its efficiency in the context of mobile networks. Therefore, we implement xNEMO; a compliant implementation of NEtwork MObility Basic Support (NEMO BS) in OMNeT++. Besides, in order to enhance the performance of TCP application, we propose to modify the TCP behaviour after a recovery from a handover. Simulations show that the cooperation between TCP and NEMO BS reduces the Application Recovery Time and enhances the performance of the TCP application.

Vehicle mobility in presence of obstructing obstacle is one of the main problems limiting the deployment of vehicular ad hoc networks. Indeed, in such a highly dynamic network, underlying routing protocols struggle to find valid routes towards destination nodes. In this paper, we evaluate the performance of Cartography Enhanced OLSR with obstacle awareness protocol (CE-OLSR-OA) as well as Position based OLSR (P-OLSR) and OLSRwith movement prediction (OLSR-MOPR) routing protocols in the context of an urban VANET with obstructing obstacles. In these three OLSR-based routing protocols, the awareness about nodes locations is differently utilized in order to sustain the stability of selected routes. Conducted simulations show the superiority of CE-OLSR compared to OLSR-MOPR and P-OLSR in terms of routes validity, throughput and end-to-end delay metrics. Furthermore, we show that CE-OLSR is more suitable to real time applications than OLSR-MOPR.

Vehicle location information is central to many location-based services and applications in VANETs. Tracking vehicles positions and maintaining an accurate up-to-date view of the entire network are not easy due to the high mobility of vehicles and consequently rapid topology changes. The design of a scalable, accurate, and efficient location service is still a very challenging issue. In this paper, we propose a lightweight hierarchical cluster-based location service in city environments (HCBLS). HCBLS integrates a logical clustering based on the city digital map and consequently does not involve extra signaling overhead. An advanced location update aggregation at different levels of the assumed hierarchy is adopted to maintain up-to-date and accurate location information. Simulation results show that HCBLS achieves much better performances than the Efficient Map-Based Location Service (EMBLS) and any regular (non-cluster-based) updating scheme. HCBLS increases the success rate by around 10%, improves the overview of the network by more than 30%, lowers the location update and query costs by more than 7 times, lowers the message delivery latency by around 3 times, and presents around 4 times better localization accuracy.

The presence of obstructing obstacles severely degrades the efficiency of routing protocols in MANETs. To mitigate the effect of these obstructing obstacles, routing in MANETs is usually based on thea prioriknowledge of the obstacle map. In this paper, we investigate rather the dynamic and autonomic detection of obstacles that might stand within the network. This is accomplished using the enhanced cartography optimized link state routing CE-OLSR with no extra signaling overhead. The evaluation of the performance of our proposed detection scheme is accomplished through extensive simulations using OMNET++. Results clearly show the ability of our proposed scheme to accurately delimit the obstacle area with high coverage and efficient precision ratios. Furthermore, we integrated the proposed scheme into CE-OLSR to make it capable of autonomously detecting and avoiding obstacles. Simulation results show the effectiveness of such an integrated protocol that provides the same route validity as that of CE-OLSR-OA which is based on thea prioriknowledge of the obstructing obstacle map.

International audience; The Machine-to-Machine (M2M) technology, currently under standardization at both the ETSI and 3GPP, is expected to be one of the most promising revenue-generating services. However, to ensure the wide spread of this technology, M2M communications should be secure, fault-tolerant and self-managed. In this work, we add to the M2M gateway (an aggregator node in the M2M architecture) the self-healing and self-optimizing autonomic capabilities. We couple at the M2M gateway level the Host Identity Protocal (HIP) with the Reachability Protocol (REAP). REAP enables a self-healed M2M communication as it detects possible failures and seamlessly rehomes an M2M established session to a new working overlay path. Furthermore, we modify REAP to ensure self-optimized M2M communications. REAP continuously monitors M2M overlay paths and always selects the best available ones in terms of RTT. We implement our solution on the OMNeT++ network simulator. Results show that M2M sessions effectively resume after an outage affecting their currently used M2M overlay paths. Results also highlight that M2M sessions autonomically select the best available M2M overlay paths.