A secure communication framework for wireless sensor networks

Today, wireless sensor networks (WSNs) are no longer a nascent technology and future networks, especially Cyber-Physical Systems (CPS) will integrate more sensor-based systems into a variety of application scenarios. Typical application areas include medical, environmental, military, and commercial enterprises. Providing security to this diverse set of sensor-based applications is necessary for the healthy operations of the overall system because untrusted entities may target the proper functioning of applications and disturb the critical decision-making processes by injecting false information into the network. One way to address this issue is to employ en-route-filtering-based solutions utilizing keys generated by either static or dynamic key management schemes in the WSN literature. However, current schemes are complicated for resource-constrained sensors as they utilize many keys and more importantly as they transmit many keying messages in the network, which increases the energy consumption of WSNs that are already severely limited in the technical capabilities and resources (i.e., power, computational capacities, and memory) available to them. Nonetheless, further improvements without too much overhead are still possible by sharing a dynamically created cryptic credential. Building upon this idea, the purpose of this thesis is to introduce an efficient and secure communication framework for WSNs. Specifically, three protocols are suggested as contributions using virtual energies and local times onboard the sensors as dynamic cryptic credentials: (1) Virtual Energy-Based Encryption and Keying (VEBEK); (2) TIme-Based DynamiC Keying and En-Route Filtering (TICK); (3) Secure Source-Based Loose Time Synchronization (SOBAS) for WSNs.Ph.D.Committee Chair: Copeland, John; Committee Co-Chair: Beyah, Raheem; Committee Member: Li, Geoffrey; Committee Member: Owen, Henry; Committee Member: Zegura, Ellen; Committee Member: Zhang, Fumi

Simplicity, reproducibility and scalability for huge wireless sensor network simulations.

Programa de P?s-Gradua??o em Ci?ncia da Computa??o. Departamento de Ci?ncia da Computa??o, Instituto de Ci?ncias Exatas e Biol?gicas, Universidade Federal de Ouro Preto.Neste trabalho apresentamos duas contribui??es para a literatura de redes de sensores sem fio (WSN). A primeira ? um modelo geral para alcan?ar a reprodutibilidade no n?vel do kernel em simuladores paralelos. Infelizmente, os usu?rios devem implementar do zero como suas simula??es se repetem em simuladores WSN, mas uma simula??o paralela ou distribu?da imp?e o princ?pio de concorr?ncia, n?o trivial de ser implementada por n?o especialistas. Testes usando o simulador chamado JSensor comprovaram que o modelo garante o n?vel mais restrito de reprodutibilidade, mesmo quando as simula??es adotam diferentes n?meros de threads ou diferentes m?quinas em m?ltiplas execu??es. A segunda contribui??o ? o simulador JSensor, um simulador paralelo de uso geral para aplica??es WSN de grande escala e algoritmos distribu?dos de alto n?vel. O JSensor introduz elementos de simula??o mais realistas, como o ambiente representado por c?lulas personaliz?veis e eventos de aplica??o que representam fen?menos naturais, como raios, vento, sol, chuva e muito mais. As c?lulas s?o colocadas em uma grade que representa o ambiente com caracter?sticas do espa?o definido pelos usu?rios, como temperatura, press?o e qualidade do ar. Avalia??es experimentais mostram que o JSensor tem boa escalabilidade em arquiteturas de computadores multi-core, alcan?ando um speedup de 7,45 em uma m?quina com 16 n?cleos com tecnologia Hyper-Threading, portanto 50% dos n?cleos s?o virtuais. O JSensor tamb?m provou ser 21% mais r?pido que o OMNeT++ ao simular um modelo do tipo flooding.In this work we present two contributions for the wireless sensor network (WSN) literature. The first one is a general model to achieve reproducibility in kernel level of parallel simulators. Unfortunately, users must implement how their simulations repeat from scratch in WSN simulators, but a parallel or distributed simulation imposes the concurrence principle, not trivial to be implemented by non-specialists. Tests using the simulator named JSensor proved that the model guarantees the most restrict level of reproducibility, even when simulations adopt different number of threads or different machines in multiple runs. The second contribution is the JSensor simulator, a parallel general purpose simulator for large scale WSN applications and high-level distributed algorithms. JSensor introduces more realistic simulation elements, such as the environment represented by customizable cells and application-events representing natural phenomena, such as lightning, wind, sun, rain and more. The cells are placed in a grid that represents the environment with characteristics of the space defined by the users, such as temperature, pressure and air quality. Experimental evaluations show that JSensor has good scalability in multi-core computer architectures, achieving a speedup of 7.45 in a machine with 16 cores with Hyper-Threading Technology, thus 50% of cores are virtual ones. JSensor also proved to be 21% faster than OMNeT++ while simulating a flooding model

Improving Multicast Communications Over Wireless Mesh Networks

In wireless mesh networks (WMNs) the traditional approach to shortest path tree based multicasting is to cater for the needs of the poorest performingnode i.e. the maximum permitted multicast line rate is limited to the lowest line rate used by the individual Child nodes on a branch. In general, this meansfixing the line rate to its minimum value and fixing the transmit power to its maximum permitted value. This simplistic approach of applying a single multicast rate for all nodes in the multicast group results in a sub-optimal trade-off between the mean network throughput and coverage area that does not allow for high bandwidth multimedia applications to be supported. By relaxing this constraint and allowing multiple line rates to be used, the mean network throughput can be improved. This thesis presents two methods that aim to increase the mean network throughput through the use of multiple line rates by the forwarding nodes. This is achieved by identifying the Child nodes responsible for reducing the multicast group rate. The first method identifies specific locations for the placement of relay nodes which allows for higher multicast branch line rates to be used. The second method uses a power control algorithm to tune the transmit power to allow for higher multicast branch line rates. The use of power control also helps to reduce the interference caused to neighbouring nodes.Through extensive computer simulation it can be shown that these two methods can lead to a four-fold gain in the mean network throughput undertypical WMN operating conditions compared with the single line rate case

Energy-aware medium access control protocols for wireless sensors network applications

The main purpose of this thesis was to investigate energy efficient Medium Access Control (MAC) protocols designed to extend the lifetime of a wireless sensor network application, such as tracking, environment monitoring, home security, patient monitoring, e.g., foetal monitoring in the last weeks of pregnancy. From the perspective of communication protocols, energy efficiency is one of the most important issues, and can be addressed at each layer of the protocol stack; however, our research only focuses on the medium access control (MAC) layer. An energy efficient MAC protocol was designed based on modifications and optimisations for a synchronized power saving Sensor MAC (SMAC) protocol, which has three important components: periodic listen and sleep, collision and overhearing avoidance and message passing. The Sensor Block Acknowledgement (SBACK) MAC protocol is proposed, which combines contention-based, scheduling-based and block acknowledgement-based schemes to achieve energy efficiency. In SBACK, the use of ACK control packets is reduced since it will not have an ACK packet for every DATA packet sent; instead, one special packet called Block ACK Response will be used at the end of the transmission of all data packets. This packet informs the sender of how many packets were received by the receiver, reducing the number of ACK control packets we intended to reduce the power consumption for the nodes. Hence more useful data packets can be transmitted. A comparison study between SBACK and SMAC protocol is also performed. Considering 0% of packet losses, SBACK decreases the energy consumption when directly compared with S-MAC, we will have always a decrease of energy consumption. Three different transceivers will be used and considering a packet loss of 10% we will have a decrease of energy consumption between 10% and 0.1% depending on the transceiver. When there are no retransmissions of packets, SBACK only achieve worst performance when the number of fragments is less than 12, after that the decrease of average delay increases with the increase of the fragments sent. When 10% of the packets need retransmission only for the TR1000 transceiver worst results occurs in terms of energy waste, all other transceivers (CC2420 and AT86RF230) achieve better results. In terms of delay if we need to retransmit more than 10 packets the SBACK protocol always achieves better performance when comparing with the other MAC protocols that uses ACK

Integrated Analysis of Environment-driven Operational Effects in Sensor Networks

There is a rapidly growing need to evaluate sensor network functionality and performance in the context of the larger environment of infrastructure and applications in which the sensor network is organically embedded. This need, which is motivated by complex applications related to national security operations, leads to a paradigm fundamentally different from that of traditional data networks. In the sensor networks of interest to us, the network dynamics depend strongly on sensor activity, which in turn is triggered by events in the environment. Because the behavior of sensor networks is sensitive to these driving phenomena, the integrity of the sensed observations, measurements and resource usage by the network can widely vary. It is therefore imperative to accurately capture the environmental phenomena, and drive the simulation of the sensor network operation by accounting fully for the environment effects. In this paper, we illustrate the strong, intimate coupling between the sensor network operation and the driving phenomena in their applications with an example sensor network designed to detect and track gaseous plumes

High Performance Communication Framework for Mobile Sinks Wireless Sensor Networks

A wireless sensor networks typically consist of thousand of nodes and each node has limited power, processing and bandwidth resources. Harvesting advances in the past decade in microelectronics, sensing, wireless communications and networking, sensor networks technology is expected to have a significant impact on our lives in the twenty-first century. Proposed applications of sensor networks include environmental monitoring, natural disaster prediction and relief, homeland security, healthcare, manufacturing, transportation, and home appliances and entertainment. However, Communication is one of the major challenges in wireless sensor networks as it is the main source for energy depletion. Improved network lifetime is a fundamental challenge of wireless sensor networks. Many researchers have proposed using mobile sinks as one possible solution to improve the lifetime of wireless sensor networks. The reason is that the typical manyto- one communication traffic pattern in wireless sensor networks imposes a heavy forwarding load on the nodes close to the sinks. However, it also introduces many research challenges such as the high communication overhead for updating the dynamic routing paths to connect to mobile sinks and packet loss problems while transmitted messages to mobile sinks. Therefore, our goal is to design a robust and efficient routing framework for both non-geographic aware and geographic aware mobile sinks wireless sensor networks. In order to achieve this goal in non-geographic based mobile sinks wireless sensor networks, we proposed a spider-net zone routing protocol to improve network efficiency and lifetime. Our proposed routing protocol utilise spider web topology inspired by the way spiders hunt prey in their web to provide reliable and high performance data delivery to mobile sinks. For routing in geographic aware based mobile sinks wireless sensor networks, we proposed a fault-tolerant magnetic coordinate routing algorithm to allow these network sensors to take advantage of geographic knowledge to build a routing protocol. Our proposed routing algorithm incorporates a coordinated routing algorithm for grid based network topology to improve network performance. Our third contribution is a component level fault diagnosis scheme for wireless sensor networks. The advantage of this scheme, causal model fault diagnosis, is that it can "deeply understand" and express the relationship among failure behaviours and node system components through causal relations. The above contributions constitute a novel routing framework to address the routing challenges in mobile sinks wireless sensor networks, Our framework considers both geographic and non-geographic aware based sensor networks to achieve energy efficient, high performance and network reliability. We have analyzed the proposed protocols and schemes and evaluated their performances using analytical study and simulations. The evaluation was based on the most important metries in wireless sensor networks, such as: power consumption and average delay. The evaluation shows that our solution is more energy efficient, improves the network performance, and provides data reliability in mobile sinks wireless sensor networks

SUIDS : a resource-efficient intrusion detection system for ubiquitous computing environments

The background of the project is based on the notion of ubiquitous computing. Ubiquitous computing was introduced as a prospective view about future usage of computers. Smaller and cheaper computer chips will enable us to embed computing ability into any appliances. Along with the convenience brought by ubiquitous computing, its inherent features also exposed its weaknesses. It makes things too easy for a malicious user to spy on others. An Intrusion Detection System (IDS) is a tool used to protect computer resources against malicious activities. Existing IDSs have several weaknesses that hinder their direct application to ubiquitous networks. These shortcomings are caused by their lack of considerations about the heterogeneity, flexibility and resource constraints of ubiquitous networks. Thus the evolution towards ubiquitous computing demands a new generation of resource-efficient IDSs to provide sufficient protections against malicious activities. SUIDS is the first intrusion detection system proposed for ubiquitous computing environments. It keeps the special requirements of ubiquitous computing in mind throughout its design and implementation. SUIDS adopts a layered and distributed system architecture, a novel user-centric design and service-oriented detection method, a new resource-sensitive scheme, including protocols and strategies, and a novel hybrid metric based algorithm. These novel methods and techniques used in SUIDS set a new direction for future research and development. As the experiment results demonstrated, SUIDS is able to provide a robust and resource-efficient protection for ubiquitous computing networks. It ensures the feasibility of intrusion detection in ubiquitous computing environments

Worldsens: development and prototyping tools for application specific wireless sensors networks

International audienceIn this paper we present Worldsens, an integrated environment for development and rapid prototyping of wireless sensor network applications. Our environment relies on software simulation to help the designer during the whole development process. The refinement is done starting from the high level design choices down to the target code implementation, debug and performance analysis. In the early stages of the design, high level parameters, like for example the node sleep and activity periods, can be tuned using WS-Net, an event driven wireless network simulator. WSNet uses models for applications, protocols and radio medium communication with a parameterized accuracy. The second step of the sensor network application design takes place after the hardware implementation choices. This second step relies on the WSim cycle accurate hardware platform simulator. WSim is used to debug the application using the real target binary code. Precise performance evaluation, including real-time analysis at the interrupt level, are made possible at this low simulation level. WSim can be connected to WSNet, in place of the application and protocol models used during the high level simulation to achieve a full distributed application simulation. WSNet and WSNet+WSim allow a continuous refinement from high level estimations down to low level real-time validation. We illustrate the complete application design process using a real life demonstrator that implements a hello protocol for dynamic neighborhood discovery in a wireless sensor network environment

Secured Sector Based Bi-path Clustering and Routing Protocol for Wireless Sensor Network

Security and efficient routing are two important parameters in sensor networks. There are few protocols that consider both routing and security. Existing methods suffer from computational overheads. In this thesis we propose SSBBCR (Secured Sector Based Bi-path Clustering and Routing) protocol that takes both these two issues into consideration. It uses bi-path routing algorithm to decrease the computational overhead as well as energy dissipation in the nodes. A key pre-distribution scheme is proposed such that nodes in the route share keys while those that are not in the route do not share keys with nodes that are in the route. Simulation results show that the proposed protocol maximizes the sensor network lifetime and achieves a high probability of connectivity. The proposed approach achieves the best performance when the network is large and the sensor nodes are deployed over a large area.Computer Science Departmen