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In most of Wireless Sensor Network (WSN) applications, it is important to associate each event’s information with its location’s information. If sensors are accurately located, the identified event (e.g., fire, accident) could be of most important in order to figure out and understand the context or situation. However, sensors localization is still an important issue in order to develop context-driven applications. This paper introduces a new scheme for sensor nodes localization in three-dimensional WSNs, denoted 3DeDV-Hop. We have implemented both algorithms the 3DeDV-Hop and 3DDV-Hop in OMNET++, and studied their performance in three dimensional wireless sensor networks. Simulation results show that the 3DeDV-Hop outperforms the basic 3DDV-Hop localization algorithm in terms of localization accuracy and the number of localized nodes.

Geographic protocols have been recently developed for data routing in wireless ad hoc networks. These protocols are based on the exact location of each sensor node, by assuming that sensor nodes are equipped with geographic positioning services or localization-based techniques. At each node, the routing decision is based only on the position of the destination node and the position of the forwarding node’s neighbors. Location-based techniques, such DV-Hop, have attracted a lot of interest in order to estimate nodes positions. In this paper, we evaluate the performance of DV-Hop localization technique for estimating nodes localization and integrate it within the greedy perimeter stateless routing protocol. Simulations have been conducted to show the effectiveness of using localization-based techniques when integrated into geographical routing protocols for wireless sensor networks.

In wireless sensor networks, several localization algorithms have been proposed to accurately locate nodes. These algorithms can be categorized into two main families: range-based and range-free. Algorithms using the range-based technique are mainly based on exact computation of the distance or the angle between two nodes (i.e., transmitter and receiver) in the network. Thus, the position can be obtained using trilateration or triangulation. Methods using the range-free technique, however, use only the network connectivity information between nodes. Nodes use the positions of the anchors; no measure of distance or angle is used. Therefore, these algorithms can only provide estimated nodes positions. In this paper, we focus on algorithms that use the range-free technique, especially DV-Hop algorithm, and we present an improved DV-Hop localization algorithm for WSNs. Simulation results show that the proposed algorithm can reduce the localization error.

International audience; Substantial research efforts on Ad hoc networks have been devoted recently to Vehicular Ad hoc NETworks (VANETs) to target Vehicle to Vehicle (V2V) and Vehicle to Roadside unit (V2R) communications in order to increase driver/vehicle safety, transport efficiency and driver comfort. VANETs are special subclass of Mobile Ad hoc NETworks (MANETs) for inter-vehicle communication and have relatively more dynamic nature compared to MANETs due to the rapid network topology changes. The development and implementation of efficient and scalable algorithms for information dissemination in VANETs is a major issue which has taken enormous attention in the last years. In this paper, an efficient distributed information dissemination approach is proposed, inspired by Ant-colony communication principles, such as scalability and adaptability that are useful for developing a decentralized architecture in highly dynamic networks. The main objective is to provide each vehicle with relevant information about its surrounding to allow drivers to be aware of undesirable events and road conditions. A "relevance" value into emergency messages is defined as an analog to pheromone throwing in Ant colony, to take an appropriate action. Simulations are conducted using NS2 network simulator and relevant metrics are evaluated under different node speeds and densities to show the effectiveness of the proposed approach.

International audience