Hamid Menouar

Visible Light Communication for Vehicular Networking: Performance Study of a V2V System Using a Measured Headlamp Beam Pattern Model

In this article, we discuss visible light communication (VLC) in the context of vehicular communication networks. With the omnipresence of light-emitting diodes (LEDs) in outdoor and automotive lightings, VLC emerges as a natural candidate for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. We first provide an overview of this emerging research area highlighting recent advances and identifying open problems for further research. Then, we present the performance evaluation of a typical V2V VLC system with realistic automative light sources. Our evaluation takes into account the measured headlamp beam pattern and the impact of road reflected light. We demonstrate that depending on the photodetector (PD) position above the ground level, a data rate of 50 Mb/s can be achieved at 70 m.

Experimental evaluation of a Routing Protocol for WSNs: RPL robustness under study

This paper presents experimental results on the Routing Protocol for Low-Power and Lossy Networks (RPL). The RPL properties in terms of delivery ratio, control packet overhead, dynamics and robustness are studied. The results are obtained by several experimentations conducted on 2 large wireless sensor network testbeds composed of more than 100 sensor nodes each. In this real-life scenario (high density and convergecast traffic), several intrinsic characteristics of RPL are underlined: path length stability but reduced delivery ratio and important overhead. To investigate the RPL robustness, we observe its behavior when facing a sudden death of several sensors and when several sensors are redeployed. RPL shows good abilities to maintain the routing process despite such events. However, the paper highlights that this ability can be reduced if only few critical nodes fail. To the best of our knowledge, it is the first study of RPL on such large platform.

Experimental evaluation of a routing protocol for wireless sensor networks: RPL under study

In this article, experimental results on the Routing Protocol for Low-Power and Lossy Networks (RPL) are presented. We study the RPL properties in terms of delivery ratio, control packet overhead and dynamicity. The results are obtained by several experimentations conducted in a large wireless sensor network testbed composed of more than 250 sensor nodes. In this real-life scenario (high density and convergcast traffic), several intrinsic characteristics of RPL are underlined: path length stability but reduced delivery ratio and important overhead. To the best of our knowledge, it is the first study of RPL on a such large platform.

Cross-layer architecture for congestion control in Vehicular Ad-hoc Networks

Vehicular Ad-hoc Networks (VANETs) are special kind of Mobile Ad-hoc Networks (MANETs). The distinctive characteristics of the VANETs include high speed of vehicular nodes and high variability in node density. Congestion detection and control protocols have been proved to be an efficient method for improving network performance and are well studied for the MANET environment. However, they often result in sub-optimal network performance for the vehicular network environment due to the specialized characteristics of VANET. In this paper we present an adaptive and distributed cross-layer congestion detection and control protocol for the VANET environment. During the congestion detection phase, information from each layer of the network protocol stack is combined and mapped on to congestion levels. In the subsequent congestion control phase parameters like contention window, transmission rate and transmit power are jointly adjusted to improve on the network performance. The effectiveness of the proposed model is evaluated through mathematical analysis and simulation-based studies.

Enhancing RPL Resilience Against Routing Layer Insider Attacks

To gather and transmit data, low cost wireless devices are often deployed in open, unattended and possibly hostile environment, making them particularly vulnerable to physical attacks. Resilience is needed to mitigate such inherent vulnerabilities and risks related to security and reliability. In this paper, Routing Protocol for Low-Power and Lossy Networks (RPL) is studied in presence of packet dropping malicious compromised nodes. Random behavior and data replication have been introduced to RPL to enhance its resilience against such insider attacks. The classical RPL and its resilient variants have been analyzed through Cooja simulations and hardware emulation. Resilient techniques introduced to RPL have enhanced significantly the resilience against attacks providing route diversification to exploit the redundant topology created by wireless communications. In particular, the proposed resilient RPL exhibits better performance in terms of delivery ratio (up to 40%), fairness and connectivity while staying energy efficient.

Design and Implementation of a Sustainable Wireless BAN Platform for Remote Monitoring of Workers Health Care in Harsh Environments

This paper presents experimental results on a body area network platform that accurately and precisely captures, processes, and wirelessly transmits six- degrees-of-freedom inertial and electrocardiogram data in a wearable, non-invasive form factor. The platform is designed to be low-energy enabling health care applications and remote monitoring of workers in harsh environments. The challenges tackled in this article include the following: (1) reducing the radio channel contention, (2) reducing the energy consumption, and (3) managing diverse Quality of Service (QoS). The system is evaluated regarding to the accuracy and the energy consumption efficiency.

Grid architecture for lightweight WSN-based area monitoring and alerts dissemination

Wireless Sensor Networks have been used for many applications especially for sites monitoring and surveillance. This contribution proposes a new grid-based architecture to monitor an area of interest that could be of a large size through a number of energy efficient sensors deployed randomly to cover the whole area. The proposed solution relays on a grid-based scheme where the monitored area is logically divided into small rectangular cells and in each cell at least one sensor is deployed. The status of the sensors located within a certain cell tells the situation in that cell either in hazard state or not, as well as the situation of other cells around. When a hazard is detected, all the deployed sensors enter into a dynamic cooperation to ensure an energy-efficient dissemination of the whole area with an alert about the new hazard. The proposed solution has been validated through intensive simulations which show an important improvement in terms of overall network overhead as well as overall network energy consumption.

HCBLS: A Hierarchical Cluster-Based Location Service in Urban Environment

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.

Advanced real-time traffic monitoring system based on V2X communications

The number of vehicles on roads keeps increasing continuously, making the management of traffic flow, especially in big cities more and more challenging. One of the key enablers for having smooth traffic flows and better mobility is to rely on real-time traffic monitoring systems. These systems allow road operators to implement intelligent traffic management strategies such as the dynamic adjustment of timing and phasing of traffic lights and the adaptive road congestion charging. Moreover, better informed travelers will plan smartly their journeys and hence potentially contribute in reducing traffic jams. Traditional real-time traffic monitoring usually get real-time data from GPS-equipped fleets and fixed sensors installed in specific locations. In this paper, a new real-time traffic monitoring based on emerging vehicular communication systems is proposed. The system enables traffic monitoring with higher reliability, accuracy, and granularity. The cluster-based V2X traffic data collection mechanism is able to gather more than 99% of the available data and reduce the overhead to one quarter when compared to other approaches.

Forwarding in VANETs: GeoNetworking

Nowadays connectivity in the vehicles is becoming the base to enable safety, traffic efficiency, and infotainment applications. These applications require to exchange information with specific geographical locations. After a decade of research and standardization activities, a dedicated technology to support forwarding in Vehicular Ad-hoc Network (VANET) called GeoNetworking has been completed in Europe. This chapter will provide an overview of GeoNetworking features and functionalities describing geographical addressing and geographical forwarding in an easy and understandable way for both technical and non-technical readers.