An adaptive timer for RPL to handle mobility in wireless sensor networks

This paper focuses on the performance of wireless sensor networks characterized by a hybrid topology composed of mobile and static sensor nodes. The Routing Protocol for Low power and lossy networks (RPL), which is standardized as an IPv6 routing protocol for low power and lossy networks, uses the trickle timer algorithm to handle changes in the network topology. However, this algorithm is not well adapted to dynamic environments. This paper enhances the trickle timer in order to fit with mobility requirements. Most of previous works have improved this algorithm without considering the random movement of nodes. In this work, the proposed timer algorithm takes into consideration the random t…

Graph Filtering of Time-Varying Signals over Asymmetric Wireless Sensor Networks

In many applications involving wireless sensor networks (WSNs), the observed data can be modeled as signals defined over graphs. As a consequence, an increasing interest has been witnessed to develop new methods to analyze graph signals, leading to the emergence of the field of Graph Signal Processing. One of the most important processing tools in this field is graph filters, which can be easily implemented distributedly over networks by means of cooperation among the nodes. Most of previous works related to graph filters assume the same connection probability in both link directions when transmitting an information between two neighboring nodes. This assumption is not realistic in practice…

A new Scheme for RPL to handle Mobility in Wireless Sensor Networks

Mobile wireless sensor networks (WSNs) are characterised by dynamic changes in the network topology leading to route breaks and disconnections. The IPv6 routing protocol for low power and lossy networks (RPL), which has become a standard, uses the Trickle timer algorithm to handle changes in the network topology. However, neither RPL nor Trickle timer are well adapted to mobility. This paper investigates the problem of supporting mobility when using RPL. It enhances RPL to fit with sensors' mobility by studying two cases. Firstly, it proposes to modify RPL in order to fit with a dynamic and hybrid topology in the context of medical applications. Secondly, it investigates a more general case…

Accurate Graph Filtering in Wireless Sensor Networks

Wireless sensor networks (WSNs) are considered as a major technology enabling the Internet of Things (IoT) paradigm. The recent emerging Graph Signal Processing field can also contribute to enabling the IoT by providing key tools, such as graph filters, for processing the data associated with the sensor devices. Graph filters can be performed over WSNs in a distributed manner by means of a certain number of communication exchanges among the nodes. But, WSNs are often affected by interferences and noise, which leads to view these networks as directed, random and time-varying graph topologies. Most of existing works neglect this problem by considering an unrealistic assumption that claims the…

An Efficient Intrusion Detection System for Selective Forwarding and Clone Attackers in IPv6-based Wireless Sensor Networks under Mobility

Security in mobile wireless sensor networks is a big challenge because it adds more complexity to the network in addition to the problems of mobility and the limited sensor node resources. Even with authentication and encryption mechanisms, an attacker can compromise nodes and get all the keying materials. Therefore, an intrusion detection system is necessary to detect and defend against the insider attackers. Currently, there is no intrusion detection system applied to IPv6-based mobile wireless sensor networks. This paper is mainly interested in detecting the selective forwarding and clone attacks because they are considered among the most dangerous attackers. In this work, the authors de…

An intrusion detection system for selective forwarding attack in IPv6-based mobile WSNs

Selective forwarding attack is considered among the most dangerous attack in wireless sensor networks, particularly in mobile environment. The attackers compromise legitimate nodes and selectively drop some packets. In addition to that, the movement of some nodes increases link failures, collisions and packet loss. So, it will be more difficult to detect malicious nodes from legitimates ones. This paper focuses on detecting selective forwarding attackers in IPv6-based mobile wireless sensor networks when the standardized IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) is used. Contrarily to previous works which propose solutions to detect selective forwarding attack in static w…

Quantization in Graph Convolutional Neural Networks

Topology design to increase network lifetime in WSN for graph filtering in consensus processes

Graph filters, which are considered as the workhorses of graph signal analysis in the emerging field of signal processing on graphs, are useful for many applications such as distributed estimation in wireless sensor networks. Many of these tasks are based on basic distributed operators such as consensus, which are carried out by sensor devices under limited energy supply. To cope with the energy constraints, this paper focuses on designing the network topology in order to maximize the network lifetime and reduce the energy consumption when applying graph filters. The problem is a complex combinatorial problem and in this work, we propose two efficient heuristic algorithms for solving it. We…

Graph Filtering with Quantization over Random Time-varying Graphs

Distributed graph filters can be implemented over wireless sensor networks by means of cooperation and exchanges among nodes. However, in practice, the performance of such graph filters is deeply affected by the quantization errors that are accumulated when the messages are transmitted. The latter is paramount to overcome the limitations in terms of bandwidth and computation capabilities in sensor nodes. In addition to quantization errors, distributed graph filters are also affected by random packet losses due to interferences and background noise, leading to the degradation of the performance in terms of the filtering accuracy. In this work, we consider the problem of designing graph filte…

Stochastic Graph Filtering Under Asymmetric Links in Wireless Sensor Networks

Wireless sensor networks (WSN s) are often characterized by random and asymmetric packet losses due to the wireless medium, leading to network topologies that can be modeled as random, time-varying and directed graphs. Most of existing works related to graph filtering in the context of WSNs assume that the probability of delivering an information from one node to a neighbor node is the same as in the reverse direction. This assumption is not realistic due to the typical link asymmetry in WSNs caused by interferences and background noise. In this work, we analyze the problem of applying stochastic graph filtering over random time-varying asymmetric network topologies. We show that it is poss…

Coded addresses in multi-hop wireless sensor networks

Topology design to reduce energy consumption of distributed graph filtering in WSN

The large number of nodes forming current sensor networks has made essential to introduce distributed mechanisms in many traditional applications. In the emerging field of graph signal processing, the distributed mechanism of information potentials constitutes a distributed graph filtering process that can be used to solve many different problems. An important limitation of this algorithm is that it is inherently iterative, which implies that the nodes incur in a repeated communication cost along the exchange periods of the filtering process. Since sensor nodes are battery powered and radio communications are one of the most energy demanding operations, in this work, we propose to redesign …