221 research outputs found
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
Performance assessment of mobility solutions for IPv6-based healthcare wireless sensor networks
This thesis focuses on the study of mobile wireless sensor networks applied to healthcare
scenarios. The promotion of better quality-of-life for hospitalized patients is addressed in this
research work with a solution that can help these patients to keep their mobility (if possible).
The solution proposed allows remote monitoring and control of patients’ health in real-time
and without interruptions. Small sensor nodes able to collect and send wirelessly the health
parameters allow for the control of the patients' health condition. A network infrastructure,
composed by several access points, allows the connection of the sensor nodes (carried by the
patients) to remote healthcare providers. To ensure continuous access to sensor nodes special
attention should be dedicated to manage the transition of these sensor nodes between
different access points’ coverage areas. The process of changing an access point attachment
of a sensor node is called handover. In that context, this thesis proposes a new handover
mechanism that can ensure continuous connection to mobile sensor nodes in a healthcare
wireless sensor network. Due to the limitations of sensor nodes’ resources, namely available
energy (these sensor nodes are typically powered by small batteries), the proposed
mechanism pays a special attention in the optimization of energy consumption. To achieve
this optimization, part of this work is dedicated to the construction of a small sensor node.
The handover mechanism proposed in this work is called Hand4MAC (handover mechanism for
MAC layer). This mechanism is compared with other mechanisms commonly used in handover
management. The Hand4MAC mechanism is deployed and validated through by simulation and
in a real testbed. The scenarios used for the validation reproduces a hospital ward. The
performance evaluation is focused in the percentage of time that senor nodes are accessible
to the network while traveling across several access points’ coverage areas and the energy
expenditures in handover processes. The experiments performed take into account various
parameters that are the following: number of sent messages, number of received messages,
multicast message usage, energy consumption, number of sensor nodes present in the
scenario, velocity of sensor nodes, and time-to-live value. In both simulation and real
testbed, the Hand4MAC mechanism is shown to perform better than all the other handover
mechanisms tested. In this comparison it was only considered the most promising handover
mechanisms proposed in the literature.Fundação para a Ciência e a Tecnologia (FCT
Federated Sensor Network architectural design for the Internet of Things (IoT)
An information technology that can combine the physical world and virtual world is desired. The Internet of Things (IoT) is a concept system that uses Radio Frequency Identification (RFID), WSN and barcode scanners to sense and to detect physical objects and events. This information is shared with people on the Internet. With the announcement of the Smarter Planet concept by IBM, the problem of how to share this data was raised. However, the original design of WSN aims to provide environment monitoring and control within a small scale local network. It cannot meet the demands of the IoT because there is a lack of multi-connection functionality with other WSNs and upper level applications. As various standards of WSNs provide information for different purposes, a hybrid system that gives a complete answer by combining all of them could be promising for future IoT applications.
This thesis is on the subject of `Federated Sensor Network' design and architectural development for the Internet of Things. A Federated Sensor Network (FSN) is a system that integrates WSNs and the Internet. Currently, methods of integrating WSNs and the Internet can follow one of three main directions: a Front-End Proxy solution, a Gateway solution or a TCP/IP Overlay solution. Architectures based on the ideas from all three directions are presented in this thesis; this forms a comprehensive body of research on possible Federated Sensor Network architecture designs. In addition, a fully compatible technology for the sensor network application, namely the Sensor Model Language (SensorML), has been reviewed and embedded into our FSN systems. The IoT as a new concept is also comprehensively described and the major technical issues discussed. Finally, a case study of the IoT in logistic management for emergency response is given. Proposed FSN architectures based on the Gateway solution are demonstrated through hardware implementation and lab tests. A demonstration of the 6LoWPAN enabled federated sensor network based on the TCP/IP Overlay solution presents a good result for the iNET localization and tracking project. All the tests of the designs have verified feasibility and achieve the target of the IoT concept
Energy aware performance evaluation of WSNs
Distributed sensor networks have been discussed for more than 30 years, but the vision
of Wireless Sensor Networks (WSNs) has been brought into reality only by the rapid advancements
in the areas of sensor design, information technologies, and wireless networks
that have paved the way for the proliferation of WSNs. The unique characteristics of
sensor networks introduce new challenges, amongst which prolonging the sensor lifetime
is the most important. Energy-efficient solutions are required for each aspect of WSN design
to deliver the potential advantages of the WSN phenomenon, hence in both existing
and future solutions for WSNs, energy efficiency is a grand challenge. The main contribution
of this thesis is to present an approach considering the collaborative nature of WSNs
and its correlation characteristics, providing a tool which considers issues from physical
to application layer together as entities to enable the framework which facilitates the
performance evaluation of WSNs. The simulation approach considered provides a clear
separation of concerns amongst software architecture of the applications, the hardware
configuration and the WSN deployment unlike the existing tools for evaluation. The
reuse of models across projects and organizations is also promoted while realistic WSN
lifetime estimations and performance evaluations are possible in attempts of improving
performance and maximizing the lifetime of the network. In this study, simulations are
carried out with careful assumptions for various layers taking into account the real time
characteristics of WSN.
The sensitivity of WSN systems are mainly due to their fragile nature when energy
consumption is considered. The case studies presented demonstrate the importance of
various parameters considered in this study. Simulation-based studies are presented,
taking into account the realistic settings from each layer of the protocol stack. Physical
environment is considered as well. The performance of the layered protocol stack in
realistic settings reveals several important interactions between different layers. These
interactions are especially important for the design of WSNs in terms of maximizing the
lifetime of the network
Smartphone: The Ultimate IoT and IoE Device
Internet of Things (IoT) and Internet of Everything (IoE) are emerging communication concepts that will interconnect a variety of devices (including smartphones, home appliances, sensors, and other network devices), people, data, and processes and allow them to communicate with each other seamlessly. These new concepts can be applied in many application domains such as healthcare, transportation, and supply chain management (SCM), to name a few, and allow users to get real-time information such as location-based services, disease management, and tracking. The smartphone-enabling technologies such as built-in sensors, Bluetooth, radio-frequency identification (RFID) tracking, and near-field communications (NFC) allow it to be an integral part of IoT and IoE world and the mostly used device in these environments. However, its use imposes severe security and privacy threats, because the smartphone usually contains and communicates sensitive private data. In this chapter, we provide a comprehensive survey on IoT and IoE technologies, their application domains, IoT structure and architecture, the use of smartphones in IoT and IoE, and the difference between IoT networks and mobile cellular networks. We also provide a concise overview of future opportunities and challenges in IoT and IoE environments and focus more on the security and privacy threats of using the smartphone in IoT and IoE networks with a suggestion of some countermeasures
Towards a self-managed framework for orchestration and integration of devices in AAL
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Secure Integration of Wireless Sensor Networks into Applications
Wireless sensors are small devices that are able to gather, process and deliver information from a physical environment to an external system. By doing so, they open new applications in different domains, such as healthcare, traffc control, defense and agriculture. The integration of Wireless Sensor Networks (WSN) with Business Applications (BA) raises technical and security related challenges. Existing approaches target technical issues such as interoperability between WSN and BAs or heterogeneity of acquired sensor data. In this work, we start by performing an analysis of the risks that such an integration of WSNs with BAs may present using the NIST SP 800-30 recommendations. We then introduce and analyze an effcient security scheme that does not use complex operations and guarantees end-to-end confidentiality of sensor data. Finally, we provide an in silico proof-of-concept and validate it using a real WSN co-developed with Cisco Systems France
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