An Energy Aware and Secure MAC Protocol for Tackling Denial of Sleep Attacks in Wireless Sensor Networks

Wireless sensor networks which form part of the core for the Internet of Things consist of resource constrained sensors that are usually powered by batteries. Therefore, careful energy awareness is essential when working with these devices. Indeed,the introduction of security techniques such as authentication and encryption, to ensure confidentiality and integrity of data, can place higher energy load on the sensors. However, the absence of security protection c ould give room for energy drain attacks such as denial of sleep attacks which have a higher negative impact on the life span ( of the sensors than the presence of security features. This thesis, therefore, focuses on tackling denial of sleep attacks from two perspectives A security perspective and an energy efficiency perspective. The security perspective involves evaluating and ranking a number of security based techniques to curbing denial of sleep attacks. The energy efficiency perspective, on the other hand, involves exploring duty cycling and simulating three Media Access Control ( protocols Sensor MAC, Timeout MAC andTunableMAC under different network sizes and measuring different parameters such as the Received Signal Strength RSSI) and Link Quality Indicator ( Transmit power, throughput and energy efficiency Duty cycling happens to be one of the major techniques for conserving energy in wireless sensor networks and this research aims to answer questions with regards to the effect of duty cycles on the energy efficiency as well as the throughput of three duty cycle protocols Sensor MAC ( Timeout MAC ( and TunableMAC in addition to creating a novel MAC protocol that is also more resilient to denial of sleep a ttacks than existing protocols. The main contributions to knowledge from this thesis are the developed framework used for evaluation of existing denial of sleep attack solutions and the algorithms which fuel the other contribution to knowledge a newly developed protocol tested on the Castalia Simulator on the OMNET++ platform. The new protocol has been compared with existing protocols and has been found to have significant improvement in energy efficiency and also better resilience to denial of sleep at tacks Part of this research has been published Two conference publications in IEEE Explore and one workshop paper

An Adaptive Fault-Tolerant Communication Scheme for Body Sensor Networks

A high degree of reliability for critical data transmission is required in body sensor networks (BSNs). However, BSNs are usually vulnerable to channel impairments due to body fading effect and RF interference, which may potentially cause data transmission to be unreliable. In this paper, an adaptive and flexible fault-tolerant communication scheme for BSNs, namely AFTCS, is proposed. AFTCS adopts a channel bandwidth reservation strategy to provide reliable data transmission when channel impairments occur. In order to fulfill the reliability requirements of critical sensors, fault-tolerant priority and queue are employed to adaptively adjust the channel bandwidth allocation. Simulation results show that AFTCS can alleviate the effect of channel impairments, while yielding lower packet loss rate and latency for critical sensors at runtime.Comment: 10 figures, 19 page

Wireless Sensor Networking in Challenging Environments

Recent years have witnessed growing interest in deploying wireless sensing applications in real-world environments. For example, home automation systems provide fine-grained metering and control of home appliances in residential settings. Similarly, assisted living applications employ wireless sensors to provide continuous health and wellness monitoring in homes. However, real deployments of Wireless Sensor Networks (WSNs) pose significant challenges due to their low-power radios and uncontrolled ambient environments. Our empirical study in over 15 real-world apartments shows that low-power WSNs based on the IEEE 802.15.4 standard are highly susceptible to external interference beyond user control, such as Wi-Fi access points, Bluetooth peripherals, cordless phones, and numerous other devices prevalent in residential environments that share the unlicensed 2.4 GHz ISM band with IEEE 802.15.4 radios. To address these real-world challenges, we developed two practical wireless network protocols including the Adaptive and Robust Channel Hopping (ARCH) protocol and the Adaptive Energy Detection Protocol (AEDP). ARCH enhances network reliability through opportunistically changing radio\u27s frequency to avoid interference and environmental noise and AEDP reduces false wakeups in noisy wireless environments by dynamically adjusting the wakeup threshold of low-power radios. Another major trend in WSNs is the convergence with smart phones. To deal with the dynamic wireless conditions and varying application requirements of mobile users, we developed the Self-Adapting MAC Layer (SAML) to support adaptive communication between smart phones and wireless sensors. SAML dynamically selects and switches Medium Access Control protocols to accommodate changes in ambient conditions and application requirements. Compared with the residential and personal wireless systems, industrial applications pose unique challenges due to their critical demands on reliability and real-time performance. We developed an experimental testbed by realizing key network mechanisms of industrial Wireless Sensor and Actuator Networks (WSANs) and conducted an empirical study that revealed the limitations and potential enhancements of those mechanisms. Our study shows that graph routing is more resilient to interference and its backup routes may be heavily used in noisy environments, which demonstrate the necessity of path diversity for reliable WSANs. Our study also suggests that combining channel diversity with retransmission may effectively reduce the burstiness of transmission failures and judicious allocation of multiple transmissions in a shared slot can effectively improve network capacity without significantly impacting reliability

Deadline-Aware Scheduling Perspectives in Industrial Wireless Networks: A Comparison between IEEE 802.15.4 and Bluetooth

In industrial contexts, most of process control applications use wired communication networks. The reliability of wired networks is indisputable and extensively demonstrated by several studies in the literature. However, it is important to consider several disadvantages provided by the use of wired technologies, like high deployment and maintenance costs and low network scalability. Although it is difficult to fully replace wired networks, wireless communication protocols have features which could undeniably affect in positive way the production mechanisms in factories. The wireless networks (WNs) are effectively used to detect and exchange information. The main communication protocols, currently available for WNs, however, do not support real-time periodic traffic flows which, as known, mainly characterize industrial networks. In this paper, we will analyze a real-time scheduling algorithm for both periodic and aperiodic traffic management, applied to networks based on IEEE 802.15.4 and Bluetooth, respectively. The main purpose of this research is to reduce, as much as possible, the packet loss on the channel, increasing at the same time the reliability of the wireless technology. Furthermore, the comparison between IEEE 802.15.4 and Bluetooth will allow to identify the more suitable communication protocol for industrial process control systems

Wireless Communication Networks for Gas Turbine Engine Testing

A new trend in the field of Aeronautical Engine Health Monitoring is the implementation of wireless sensor networks (WSNs) for data acquisition and condition monitoring to partially replace heavy and complex wiring harnesses, which limit the versatility of the monitoring process as well as creating practical deployment issues. Using wireless technologies instead of fixed wiring will fuel opportunities for reduced cabling, faster sensor and network deployment, increased data acquisition flexibility and reduced cable maintenance costs. However, embedding wireless technology into an aero engine (even in the ground testing application considered here) presents some very significant challenges, e.g. a harsh environment with a complex RF transmission environment, high sensor density and high data-rate. In this paper we discuss the results of the Wireless Data Acquisition in Gas Turbine Engine Testing (WIDAGATE) project, which aimed to design and simulate such a network to estimate network performance and de-risk the wireless techniques before the deployment

A MAC protocol for quality of service provisioning in adaptive biomedical wireless sensor networks

Doctorate program on Electronics and Computer EngineeringNew healthcare solutions are being explored to improve the quality of care and the quality of life of patients, as well as the sustainability and efficiency of the healthcare services. In this context, wireless sensor networks (WSNs) constitute a key technology for closing the loop between patients and healthcare providers, as WSNs provide sensing ability, as well as mobility and portability, essential characteristics for wide acceptance of wireless healthcare technology. Despite the recent advances in the field, the wide adoption of healthcare WSNs is still conditioned by quality of service (QoS) issues, namely at the medium access control (MAC) level. MAC protocols currently available for WSNs are not able to provide the required QoS to healthcare applications in scenarios of medical emergency or intensive medical care. To cover this shortage, the present work introduces a MAC protocol with novel concepts to assure the required QoS regarding the data transmission robustness, packet delivery deadline, bandwidth efficiency, and energy preservation. The proposed MAC protocol provides a new and efficient dynamic reconfiguration mechanism, so that relevant operational parameters may be redefined dynamically in accordance with the patients’ clinical state. The protocol also provides a channel switching mechanism and the capacity of forwarding frames in two-tier network structures. To test the performance of the proposed MAC protocol and compare it with other MAC protocols, a simulation platform was implemented. In order to validate the simulation results, a physical testbed was implemented to replicate the tests and verify the results. Sensor nodes were specifically designed and assembled to implement this physical testbed. New healthcare solutions are being explored to improve the quality of care and the quality of life of patients, as well as the sustainability and efficiency of the healthcare services. In this context, wireless sensor networks (WSNs) constitute a key technology for closing the loop between patients and healthcare providers, as WSNs provide sensing ability, as well as mobility and portability, essential characteristics for wide acceptance of wireless healthcare technology. Despite the recent advances in the field, the wide adoption of healthcare WSNs is still conditioned by quality of service (QoS) issues, namely at the medium access control (MAC) level. MAC protocols currently available for WSNs are not able to provide the required QoS to healthcare applications in scenarios of medical emergency or intensive medical care. To cover this shortage, the present work introduces a MAC protocol with novel concepts to assure the required QoS regarding the data transmission robustness, packet delivery deadline, bandwidth efficiency, and energy preservation. The proposed MAC protocol provides a new and efficient dynamic reconfiguration mechanism, so that relevant operational parameters may be redefined dynamically in accordance with the patients’ clinical state. The protocol also provides a channel switching mechanism and the capacity of forwarding frames in two-tier network structures. To test the performance of the proposed MAC protocol and compare it with other MAC protocols, a simulation platform was implemented. In order to validate the simulation results, a physical testbed was implemented to replicate the tests and verify the results. Sensor nodes were specifically designed and assembled to implement this physical testbed. Preliminary tests using the simulation and physical platforms showed that simulation results diverge significantly from reality, if the performance of the WSN software components is not considered. Therefore, a parametric model was developed to reflect the impact of this aspect on a physical WSN. Simulation tests using the parametric model revealed that the results match satisfactorily those obtained in reality. After validating the simulation platform, comparative tests against IEEE 802.15.4, a prominent standard used in many wireless healthcare systems, showed that the proposed MAC protocol leads to a performance increase regarding diverse QoS metrics, such as packet loss and bandwidth efficiency, as well as scalability, adaptability, and power consumption. In this way, AR-MAC is a valuable contribution to the deployment of wireless e-health technology and related applications.Novas soluções de cuidados de saúde estão a ser exploradas para melhorar a qualidade de tratamento e a qualidade de vida dos pacientes, assim como a sustentabilidade e eficiência dos serviços de cuidado de saúde. Neste contexto, as redes de sensores sem fios (wireless sensor networks - WSN) são uma tecnologia chave para fecharem o ciclo entre os pacientes e os prestadores de cuidados de saúde, uma vez que as WSNs proporcionam não só capacidade sensorial mas também mobilidade e portabilidade, caracteristicas essenciais para a aceitação à larga escala da tecnologia dos cuidados de saúde sem fios. Apesar dos avanços recentes na área, a aceitação genérica das WSNs de cuidados de saúde ainda está condicionada por aspectos relacionados com a qualidade de serviço (quality of service - QoS), nomeadamente ao nível do controlo de acesso ao meio (medium access control - MAC). Os protocolos MAC actualmente disponíveis para WSNs são incapazes de fornecer a QoS desejada pelas aplicações médicas em cenários de emergência ou cuidados médicos intensivos. Para suprimir esta carência, o presente trabalho apresenta um protocolo MAC com novos conceitos a fim de assegurar a QoS respeitante à robustez de transmissão de dados, ao limite temporal da entrega de pacotes, à utilização da largura de banda e à preservação da energia eléctrica. O protocolo MAC proposto dispõe de um novo e eficiente mecanismo de reconfiguração para que os parâmetros operacionais relevantes possam ser redefinidos dinamicamente de acordo com o estado de saúde do paciente. O protocolo também oferece um mecanismo autónomo de comutação de canal, bem como a capacidade de encaminhar pacotes em redes de duas camadas. Para testar o desempenho do protocolo MAC proposto e compará-lo com outros protocolos MAC foi implementada uma plataforma de simulação. A fim de validar os resultados da simulação foi também implementada uma plataforma física para permitir replicar os testes e verificar os resultados. Esta plataforma física inclui nós sensoriais concebidos e construídos de raiz para o efeito. Testes preliminares usando as plataformas de simulação e física mostraram que os resultados de simulação divergem significativamente da realidade, caso o desempenho dos componentes do software presentes nos componentes da WSN não seja considerado. Por conseguinte, desenvolveu-se um modelo paramétrico para reflectir o impacto deste aspecto numa WSN real. Testes de simulação efectuados com o modelo paramétrico apresentaram resultados muito satisfatórios quando comparados com os obtidos na realidade. Uma vez validada a plataforma de simulação, efectuaram-se testes comparativos com a norma IEEE 802.15.4, proeminentemente usada em projectos académicos de cuidados de saúde sem fios. Os resultados mostraram que o protocolo MAC conduz a um desempenho superior no tocante a diversas métricas QoS, tais como perdas de pacotes e utilização de largura de banda, bem como no respeitante à escalabilidade, adaptabilidade e consumo de energia eléctrica. Assim sendo, o protocolo MAC proposto representa um valioso contributo para a concretização efectiva dos cuidados de saúde sem fios e suas aplicações

A Comprehensive Approach to WSN-Based ITS Applications: A Survey

In order to perform sensing tasks, most current Intelligent Transportation Systems (ITS) rely on expensive sensors, which offer only limited functionality. A more recent trend consists of using Wireless Sensor Networks (WSN) for such purpose, which reduces the required investment and enables the development of new collaborative and intelligent applications that further contribute to improve both driving safety and traffic efficiency. This paper surveys the application of WSNs to such ITS scenarios, tackling the main issues that may arise when developing these systems. The paper is divided into sections which address different matters including vehicle detection and classification as well as the selection of appropriate communication protocols, network architecture, topology and some important design parameters. In addition, in line with the multiplicity of different technologies that take part in ITS, it does not consider WSNs just as stand-alone systems, but also as key components of heterogeneous systems cooperating along with other technologies employed in vehicular scenarios

Reliability and Energy Efficiency Enhancement for Emergency-Aware Wireless Body Area Networks (WBAN)

Medium Access Control (MAC) protocols based on Time Division Multiple Access (TDMA) can improve the reliability and efficiency of WBAN. However, traditional static TDMA techniques adopted by IEEE 802.15.4 and IEEE 802.15.6 do not sufficiently consider the channel status or the buffer requirements of the nodes within heterogeneous contexts. Although there are some solutions that have been proposed to alleviate the effect of the deep fade in WBAN channel by adopting dynamic slot allocation, these solutions still suffer from some reliability and energy efficiency issues and they do not avoid channel deep fading. This paper presents two novel and generic TDMA based techniques to improve WBAN reliability and energy efficiency. Both techniques synchronize nodes adaptively whilst tackling their channel and buffer status in normal and emergency contexts. Extensive simulation experiments using various traffic rates and time slot lengths demonstrate that the proposed techniques improve the reliability and the energy efficiency compared to IEEE 802.15.4 and IEEE 802.15.6 in both situations, the normal and emergency contexts. This improvement has been achieved in terms of packet loss, up to 90% and energy consumption, up to 13%, confirming the significant enhancements made by the developed scheduling techniques