Farid Lalem

A Distributed Multi-path Routing Algorithm to Balance Energy Consumption in Wireless Sensor Networks

Abstract A large use of applications of Wireless Sensor Networks (WSNs) pushes researchers to design and improve protocols and algorithms against the encountered challenges. One of the main goals is data gathering and routing to the base station (through the sink nodes) with lack of acknowledgement and where each node has no information about the network. Unbalanced energy consumption during the data routing process is an inherent problem in WSNs due to the limited energy capacity of the sensor nodes. In fact, WSNs require load balancing algorithms that make judicious use of the limited energy resource to route the gathered data to the sink node. In this paper, we propose a balanced multi-path routing algorithm by focusing on the residual energy and the hop count of each node to discover the best routes and to insert them into the routing table. The main idea of this algorithm comes from Ant Colony Optimization (ACO) and automata network modelization. Hence, the potential performance of the proposed algorithm relies on the best route to be selected which should have the minimum number of hops, the maximum energy and weighted energy between participating nodes to extend the lifetime of the network.

D-LPCN: A Distributed Least Polar-angle Connected Node Algorithm for Finding the Boundary of a Wireless Sensor Network

A boundary of wireless sensor networks (WSNs) can be used in many fields, for example, to monitor a frontier or a secure place of strategic sensitive sites like oil fields or frontiers of a country. This situation is modeled as the problem of finding a polygon hull in a connected Euclidean graph, which represents a minimal set of connected boundary nodes. In this paper we propose a new algorithm called D-LPCN (Distributed Least Polar-angle Connected Node) which represents the distributed version of the LPCN algorithm introduced in [1]. In each iteration, any boundary node, except the first one, chooses its nearest polar angle node among its neighbors with respect to the node found in the previous iteration. The first starting node can be automatically determined using the Minimum Finding algorithm, which has two main advantages. The first one is that the algorithm works with any type of a connected network, given as planar or not. Furthermore, it takes into account any blocking situation and contains the necessary elements to avoid them. The second advantage is that the algorithm can determine all the boundaries of the different connected parts of the network. The proposed algorithm is validated using the CupCarbon, Tossim and Contiki simulators. It has also been implemented using real sensor nodes based on the TelosB and Arduino/XBee platforms. We have estimated the energy consumption of each node and we have found that the consumption of the network depends on the number of the boundary nodes and their neighbors. The simulation results show that the proposed algorithm is less energy consuming than the existing algorithms and its distributed version is less energy consuming than the centralized version.

Boundary node failure detection in wireless sensor networks

Wireless Sensor Networks (WSNs) are an important tool for monitoring strategic and dangerous sites where high security is required. Failure detection for sensor nodes in this specified application is a major concern. The failure of any system may cause losses such as economical, equipment damage and even risks for human lives. Moreover, failures are unavoidable in WSNs due to hardware constraints, hostile environment, unattended deployment and limited resources. This paper proposes a fully distributed approach, called Boundary Node Failure Detection (BNFD), for an efficient boundary control based on the determination of the WSN boundary. This one is determined using an algorithm which has the property to determine in each iteration the one-hop neighbor of the current boundary sensor. Hence, each boundary sensor knows its direct next boundary neighbor and can communicate with it in order to periodically test its presence. When a situation of failure is detected, a network restructuring will be launched to find a new boundary and an alarm will be triggered. The proposed approach has been implemented and simulated with the Castalia simulator. The simulation results show that the proposed method is energy efficient.

Faulty Data Detection in Wireless Sensor Networks Based on Copula Theory

Wireless Sensor Networks (WSNs) are a powerful instrument for monitoring and recording physical phenomena. Very often the quality of the sensed data collected by sensor nodes is affected by noise and errors, events, and malicious attacks. Also, the processing and the transmitting of this data over the network may drain the amount of available resources of WSNs and decrease rapidly the network lifetime. Therefore, there is an urgent need to detect faulty data in order to insure the reliability of data and keep the resource of WSNs at a high level. In this paper, we propose a new approach for faulty data detection in WSNs based on Copula theory. Our experimental results on real data sets collected by real sensor networks show that a significant percentage of the data are faulty.

A lightweight only receiver clock synchronization technique for wireless sensor networks

Since the birth of computer networks and distributed systems, the clock synchronization issue has been considered as a major challenge. Unlike classical networks, which aim to provide high quality service without power restriction, the primary purpose of most sensor network protocols is to economize as much as possible the energy in order to enhance the networks lifetime. In fact, the importance to have clocks synchronized resides in the fact that a wide range of communication protocols and applications necessitate a common notion of time for the overall network nodes to operate perfectly. In this paper, we propose a new clock synchronization algorithm, referred to as Lightweight Only Receiver Clock Synchronization (LORCS). As communication between nodes consumes significant amounts of energy, our technique aims to minimize the number of exchanged timing messages during a synchronization round. To this end, neighbor nodes in LORCS synchronize their local clocks with the reference point by only receiving synchronization messages without transmitting any such message. Simulation results show the effectiveness of LORCS compared to the RBS protocol, a standard benchmark clock synchronization protocol.

A distributed security protocol designed for the context of internet of things

In the field of Internet of Things (IoT), many encryption protocols for distributed wireless communication technology have been proposed for use in various applications such as monitoring, healthcare, product management, workplace, home support and surveillance [1]. An IoT system can be looked at as a highly dynamic distributed and networked system composed of a large number of smart devices. In fact, such connected devices suffer from the limitation of resources in terms of computing, energy, bandwidth and storage. Hence, IoT application scenarios require methods to adapt to highly diverse contexts with different available resources and possibly dynamic environments. In this paper, we address these issues by proposing an efficient technique for data protection in the context of IoT. A distributed network architecture is used, where each node is in charge to deliver and/or forward data. The aim is to use efficient operations to protect the exchanged data. The proposed technique ensures the exchanged data to be effectively and securely controlled with a low overhead compared to the classical approaches. The proposed protocol shows its efficiency in terms of overhead, speed, energy and security measurements.

Distributed faulty sensor node detection in wireless sensor networks based on copula theory

Wireless Sensor Networks (WSNs) are arising from the proliferation of Micro-Electro-Mechanical Systems (MEMS) technology as an important new area in wireless technology. They are composed of tiny devices which monitor physical or environmental conditions such as temperature, pressure, motion or pollutants, etc. Moreover, the accuracy of individual sensor node readings is decisive in WSN applications. Hence, detecting nodes with faulty sensors can strictly influence the network performance and extend the network life-time. In this paper, we propose a new approach for faulty sensor node detection in WSNs based on Copula theory. The obtained experimental results on real datasets collected from real sensor networks show the effectiveness of our approach.1

A copula based approach for measurement validity verification in wireless sensor networks

Outlier detection is the process of identifying the data objects that do not comply with the normal behavior of the defined data model. Used in automated data analysis, it ensures the desired data quality and reliability. This field has attracted increasing attention in the wireless sensor network domain, using methods from machine learning, data mining, and statistics. In this paper, we propose a novel outlier detection approach based on Copula theory. This powerful theory allows to model the dependency between data measurements in a formal and statistical way. We have evaluated our proposed approach with a real world dataset. Our results show a detection rate of 85.90% and an error rate of 0.87%.

LOGO: A New Distributed Leader Election Algorithm in WSNs with Low Energy Consumption

The Leader Election Algorithm is used to select a specific node in distributed systems. In the case of Wireless Sensor Networks, this node can be the one having the maximum energy, the one situated on the extreme left in a given area or the one having the maximum identifier. A node situated on the extreme left, for instance, can be used to find the boundary nodes of a network embedded in the plane. The classical algorithm allowing to find such a node is called the Minimum Finding Algorithm. In this algorithm, each node sends its value in a broadcast mode each time a better value is received. This process is very energy consuming and not reliable since it may be subject to an important number of collisions and lost messages. In this paper, we propose a new algorithm called LOGO (Local Optima to Global Optimum) where some local leaders will send a message to a given node, which will designate the global leader. This process is more reliable since broadcast messages are sent only twice by each node, and the other communications are based on a direct sending. The obtained results show that the proposed algorithm reduces the energy consumption with rates that can exceed 95% compared with the classical Minimum Finding Algorithm.