A comprehensive survey of wireless body area networks on PHY, MAC, and network layers solutions

Recent advances in microelectronics and integrated circuits, system-on-chip design, wireless communication and intelligent low-power sensors have allowed the realization of a Wireless Body Area Network (WBAN). A WBAN is a collection of low-power, miniaturized, invasive/non-invasive lightweight wireless sensor nodes that monitor the human body functions and the surrounding environment. In addition, it supports a number of innovative and interesting applications such as ubiquitous healthcare, entertainment, interactive gaming, and military applications. In this paper, the fundamental mechanisms of WBAN including architecture and topology, wireless implant communication, low-power Medium Access Control (MAC) and routing protocols are reviewed. A comprehensive study of the proposed technologies for WBAN at Physical (PHY), MAC, and Network layers is presented and many useful solutions are discussed for each layer. Finally, numerous WBAN applications are highlighted

Design of Simulator for Energy Efficient Clustering in Mobile Ad Hoc Networks

The research on various issues in Mobile ad hoc networks are getting popularity because of its challenging nature and all time connectivity to communicate. MANET (Mobile Ad-hoc Networks) is a random deployable network where devices are mobile with dynamic topology. In the network topology, each device is termed as a node and the virtual connectivity among each node is termed as the link .Nodes in a network are dynamically organized into virtual partitions called clusters. Network simulators provide the platform to analyse and imitate the working of computer networks along with the typical devices, traffic and other entities. Cluster heads being the communication hotspots tend to drain its battery power rapidly while serving its member nodes. Further, energy consumption is a key factor that hinders the deploy ability of a real ad hoc and sensor network. It is due to the limited life time of the battery powered devices that motivates intense research into energy efficient design of operating systems, protocols and hardware devices. Clustering is a proven solution to preserve the battery power of certain nodes. In the mechanism of clustering, there exists a cluster head in every cluster that works similar to a base station in the cellular architecture. Cluster heads being the communication hotspots tend to drain its battery power rapidly while serving its member nodes. Further, energy consumption is a key factor that hinders the deploy ability of a real ad hoc and sensor network. It is due to the limited life time of the battery powered devices that motivates intense research into energy efficient design of operating systems, protocols and hardware devices. The mobile ad hoc network can be modelled as a unidirectional graph G = (V, L) where V is the set of mobile nodes and L is the set of links that exist between the nodes. We assume that there exists a bidirectional link L between the nodes and when the distance between the nodes < (transmission range) of the nodes. In the dynamic network the cardinality of the nodes remains constant, but the cardinality of links changes due to the mobility of the nodes. Network simulators are used by researchers, developers and engineers to design various kinds of networks, simulate and then analyze the effect of various parameters on the network performance. A typical network simulator encompasses a wide range of networking technologies and can help the users to build complex networks from basic building blocks such as a variety of nodes and links. The objective of our work is to design a simulator for energy efficient clustering so that the data flow as well as the control flow could be easily handled and maintained. The proposed energy efficient clustering algorithm is a distributed algorithm that takes into account the consumed battery power of a node and its average transmission power for serving the neighbour nodes as the parameters to decide its suitability to act as a cluster head. These two parameters are added with different weight factors to find the weights of the individual nodes. After the clusters are formed, gateway nodes are selected in the network that help for the inter cluster communication. The graph for the number of cluster heads selected for different number of nodes are also drawn to study the functionality of the simulator

A Lightweight Authentication Framework for Wireless Sensor Networks

Wireless Sensor Network (WSN) is emerging as a dominant technology with its applications in areas like agriculture, communication, environment monitoring, and surveillance. The inherited vulnerability and resource-constrained nature of sensor nodes led researchers to propose many lightweight cryptographic protocols for WSN. These sensors are low-cost, low energy, have low processing capability and have low storage restrictions. WSN suffers from many risks because of these unique constraints. This paper proposes a new lightweight security framework for WSNs and covers different lightweight cryptographic schemes for WSN applications. The aim is to provide cryptographic primitives for integrity, confidentiality, and protection from the man-in-the-middle and reply attacks. The work is based solely on symmetric cryptography and it has four phases; Network Initialization, Node Initialization, Nodes Communication, and Node Authentication. This work adopts the Low-Energy Adaptive Clustering Hierarchy (LEACH) framework, which deploys random rotation to distribute the energy among a group of nodes. The probability of attacking in LEACH is higher at cluster head and member nodes. Therefore, data transmission among communicated nodes is encrypted over multiple levels of protection by dynamic session keys to provide a high level of security. In addition, an authentication ticket is provided by a cluster head for each authenticated node to identify another node. The session keys are dynamically generated and updated during the communication to prevent compromising or capturing the keys. Through simulation and evaluation of the system, the results showed less energy consumption and efficient cryptographic primitive were compared with existing scheme

Unified Role Assignment Framework For Wireless Sensor Networks

Wireless sensor networks are made possible by the continuing improvements in embedded sensor, VLSI, and wireless radio technologies. Currently, one of the important challenges in sensor networks is the design of a systematic network management framework that allows localized and collaborative resource control uniformly across all application services such as sensing, monitoring, tracking, data aggregation, and routing. The research in wireless sensor networks is currently oriented toward a cross-layer network abstraction that supports appropriate fine or course grained resource controls for energy efficiency. In that regard, we have designed a unified role-based service paradigm for wireless sensor networks. We pursue this by first developing a Role-based Hierarchical Self-Organization (RBSHO) protocol that organizes a connected dominating set (CDS) of nodes called dominators. This is done by hierarchically selecting nodes that possess cumulatively high energy, connectivity, and sensing capabilities in their local neighborhood. The RBHSO protocol then assigns specific tasks such as sensing, coordination, and routing to appropriate dominators that end up playing a certain role in the network. Roles, though abstract and implicit, expose role-specific resource controls by way of role assignment and scheduling. Based on this concept, we have designed a Unified Role-Assignment Framework (URAF) to model application services as roles played by local in-network sensor nodes with sensor capabilities used as rules for role identification. The URAF abstracts domain specific role attributes by three models: the role energy model, the role execution time model, and the role service utility model. The framework then generalizes resource management for services by providing abstractions for controlling the composition of a service in terms of roles, its assignment, reassignment, and scheduling. To the best of our knowledge, a generic role-based framework that provides a simple and unified network management solution for wireless sensor networks has not been proposed previously

Adaptive remote visualization system with optimized network performance for large scale scientific data

This dissertation discusses algorithmic and implementation aspects of an automatically configurable remote visualization system, which optimally decomposes and adaptively maps the visualization pipeline to a wide-area network. The first node typically serves as a data server that generates or stores raw data sets and a remote client resides on the last node equipped with a display device ranging from a personal desktop to a powerwall. Intermediate nodes can be located anywhere on the network and often include workstations, clusters, or custom rendering engines. We employ a regression model-based network daemon to estimate the effective bandwidth and minimal delay of a transport path using active traffic measurement. Data processing time is predicted for various visualization algorithms using block partition and statistical technique. Based on the link measurements, node characteristics, and module properties, we strategically organize visualization pipeline modules such as filtering, geometry generation, rendering, and display into groups, and dynamically assign them to appropriate network nodes to achieve minimal total delay for post-processing or maximal frame rate for streaming applications. We propose polynomial-time algorithms using the dynamic programming method to compute the optimal solutions for the problems of pipeline decomposition and network mapping under different constraints. A parallel based remote visualization system, which comprises a logical group of autonomous nodes that cooperate to enable sharing, selection, and aggregation of various types of resources distributed over a network, is implemented and deployed at geographically distributed nodes for experimental testing. Our system is capable of handling a complete spectrum of remote visualization tasks expertly including post processing, computational steering and wireless sensor network monitoring. Visualization functionalities such as isosurface, ray casting, streamline, linear integral convolution (LIC) are supported in our system. The proposed decomposition and mapping scheme is generic and can be applied to other network-oriented computation applications whose computing components form a linear arrangement

Energy efficient clustering and secure data aggregation in wireless sensor networks

Communication consumes the majority of a wireless sensor network\u27s limited energy. There are several ways to reduce the communication cost. Two approaches used in this work are clustering and in-network aggregation. The choice of a cluster head within each cluster is important because cluster heads use additional energy for their responsibilities and that burden needs to be carefully distributed. We introduce the energy constrained minimum dominating set (ECDS) to model the problem of optimally choosing cluster heads in the presence of energy constraints. We show its applicability to sensor networks and give an approximation algorithm of O(log n) for solving the ECDS problem. We propose a distributed algorithm for the constrained dominating set which runs in O(log n log [triangle]) rounds with high probability. We show experimentally that the distributed algorithm performs well in terms of energy usage, node lifetime, and clustering time and thus is very suitable for wireless sensor networks. Using aggregation in wireless sensor networks is another way to reduce the overall communication cost. However, changes in security are necessary when in- network aggregation is applied. Traditional end-to-end security is not suitable for use with in-network aggregation. A corrupted sensor has access to the intermediate data and can falsify results. Additively homomorphic encryption allows for aggregation of encrypted values, with the result being the same as the result as if unencrypted data were aggregated. Using public key cryptography, digital signatures can be used to achieve integrity. We propose a new algorithm using homomorphic encryption and additive digital signatures to achieve confidentiality, integrity and availability for in- network aggregation in wireless sensor networks. We prove that our digital signature algorithm which is based on Elliptic Curve Digital Signature Algorithm (ECDSA) is at least as secure as ECDSA. Even without in-network aggregation, security is a challenge in wireless sensor networks. In wireless sensor networks, not all messages need to be secured with the same level of encryption. We propose a new algorithm which provides adequate levels of security while providing much higher availablility [sic] than other security protocols. Our approach uses similar amounts of energy as a network without security --Abstract, page iv

Wireless Sensor Networks Formation: Approaches and Techniques

Nowadays, wireless sensor networks (WSNs) emerge as an active research area in which challenging topics involve energy consumption, routing algorithms, selection of sensors location according to a given premise, robustness, efficiency, and so forth. Despite the open problems in WSNs, there are already a high number of applications available. In all cases for the design of any application, one of the main objectives is to keep the WSN alive and functional as long as possible. A key factor in this is the way the network is formed. This survey presents most recent formation techniques and mechanisms for the WSNs. In this paper, the reviewed works are classified into distributed and centralized techniques. The analysis is focused on whether a single or multiple sinks are employed, nodes are static or mobile, the formation is event detection based or not, and network backbone is formed or not. We focus on recent works and present a discussion of their advantages and drawbacks. Finally, the paper overviews a series of open issues which drive further research in the area