An objective based classification of aggregation techniques for wireless sensor networks

Wireless Sensor Networks have gained immense popularity in recent years due to their ever increasing capabilities and wide range of critical applications. A huge body of research efforts has been dedicated to find ways to utilize limited resources of these sensor nodes in an efficient manner. One of the common ways to minimize energy consumption has been aggregation of input data. We note that every aggregation technique has an improvement objective to achieve with respect to the output it produces. Each technique is designed to achieve some target e.g. reduce data size, minimize transmission energy, enhance accuracy etc. This paper presents a comprehensive survey of aggregation techniques that can be used in distributed manner to improve lifetime and energy conservation of wireless sensor networks. Main contribution of this work is proposal of a novel classification of such techniques based on the type of improvement they offer when applied to WSNs. Due to the existence of a myriad of definitions of aggregation, we first review the meaning of term aggregation that can be applied to WSN. The concept is then associated with the proposed classes. Each class of techniques is divided into a number of subclasses and a brief literature review of related work in WSN for each of these is also presented

Performance Evaluation of Broadcasting Protocols for Ad Hoc and Sensor Networks.

In ad hoc and sensor networks, the simplest and most widely used approach to broadcast is blind flooding, which lets every node in the network to rebroadcast a receiving packet to all its neighbors. This causes redundancy of broadcast packets and results in unnecessary collision and bandwidth waste. To overcome these problems, a number of research groups have proposed more efficient broadcasting schemes with the goal of minimizing the re-transmissions, while still guaranteeing that a broadcast packet is delivered to all the nodes in the network. Multipoint relay (MPR) and dominating set (DS) based broadcasting schemes can effectively improve the broadcasting efficiency while providing reliable broadcasting. The neighbor elimination scheme (NES) can improve any broadcasting protocol as an added feature. In this paper, we evaluate the performance of MPR (source dependent), MPR-DS (source-independent MPR), and DS based broadcasting protocols. We add NES to these three schemes separately and evaluate the performance of the resulted protocols. In our experiments, we use the random unit graphs to model the ad hoc and sensor networks. Each of the studied protocols has scenarios under which it has the best performance. Our experiments demonstrate that, without applying neighbor elimination scheme, MPR based protocol requires fewest retransmissions (however, each retransmission is with a longer message including list of forwarding neighbors). DS and MP-RDS schemes benefit significantly from the neighbor elimination technique in terms of the ratio of re-broadcasting nodes and the message redundancy on both transmitting and non-transmitting nodes, while MPR benefits marginally. After adding the neighbor elimination scheme, three new protocols behave almost equally well in terms of rebroadcast message counts. MPR-NES method is narrowly the best when the message that is broadcasted is very large one, and the network is dynamic. MPR-DS-NES is narrowly the best when the broadcast message is not very large, and the network is stable (this method requires the third round of preprocessing HELLO messages). Overall, DS-NES appears to be the most robust, taking all measurements and parameters into acount, because it remains competitive under all scenarios, and has significant advantages over MPR-DS-NES in dynamic scenarios, and significant advantages over MPR-NES when the broadcast message is not very large, because MPR has overhead in packet lengths

Redundancy and Synchronisation Management in Mission- and Time-Critical Wireless Sensor Networks

Wireless sensor networks (WSNs) are a technology that has been increasingly adopted thanks to their ability to inexpensively and safely gather information in difficult-to-access environments. Because of this they are an invaluable tool to gather knowledge about health, usage, and performance parameters of products in any environment as well as identify the onset of, and avoid or mitigate, catastrophic failures. This chapter will introduce the benefits that WSNs can bring to the process of knowledge management for the development and maintenance of products as well as discuss emerging research trends regarding two prominent concerns inherent to WSNs: redundancy management and synchronisation. After reviewing these results, their impact and applicability to mission-critical applications will be discussed, as well as the interaction between the solutions

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

Study of Multipoint-to-Point and Broadcast Traffic Performance in RPL

Recent trends in Wireless Sensor Networks (WSNs) have suggested converging to such being IPv6-based. to this effect, the Internet Engineering Task Force has chartered a Working Group to develop a routing protocol specification, enabling IPv6-based multi-hop Wireless Sensor Networks. This routing protocol, denoted RPL, has been under development for approximately a year, and this memorandum takes a critical look at the state of advancement hereof: it provides a brief algorithmic description of the protocol, and discusses areas where -- in the authors view -- further efforts are required in order for the protocol to become a viable candidate for general use in WSNs. Among these areas is the lack of a proper broadcast mechanism. This memorandum suggests two such broadcast mechanisms, both aiming at (i) exploiting the existing routing state of RPL, while (ii) requiring no additional state maintenance, and studies the performance of RPL and of these suggested mechanisms.Les tendances récentes dans les réseaux de capteurs sans fil (Wireless Sensor Networks --WSNs) suggèrent une convergence vers des réseaux IPv6. A cet effet, l'IETF (Internet Engineering Task Force) a mis sur pied un groupe de travail pour élaborer la spécification d'un protocole de routage s'appliquant aux réseaux de capteurs sans fil multi-hop basés sur IPv6. Ce protocole de routage, appelé RPL, est en cours de développement depuis environ un an. Cet article présente un examen critique de son état d'avancement. Après une brève description algorithmique du protocole, une discussion est proposée sur des domaines, où selon les auteurs, des efforts supplémentaires sont nécessaires pour que le protocole puisse devenir candidat viable à une utilisation généralisée dans les réseaux de capteurs sans fil. Parmi ces domaines se trouve l'absence d'un mécanisme de diffusion approprié. Cet article suggère deux mécanismes de diffusion, tous deux avec l'objectif (i) de pouvoir exploiter l'état de routage actuel du protocole RPL (ii) sans requérir à une maintenance supplémentaire de cet état. Il étudie également les performances de RPL et des deux mécanismes de diffusion proposés