Bluetooth-Based Sensor Networks for Remotely Monitoring the Physiological Signals of a Patient

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”Integrating intelligent medical microsensors into a wireless communication network makes it possible to remotely collect physiological signals of a patient, release the patient from being tethered to monitoring medical instrumentations, and facilitate the patient's early hospital discharge. This can further improve life quality by providing continuous observation without the need of disrupting the patient's normal life, thus reducing the risk of infection significantly, and decreasing the cost of the hospital and the patient. This paper discusses the implementation issues, and describes the overall system architecture of our developed Bluetooth sensor network for patient monitoring and the corresponding heart activity sensors. It also presents our approach to developing the intelligent physiological sensor nodes involving integration of Bluetooth radio technology, hardware and software organization, and our solutions for onboard signal processing.Peer reviewe

Communication blades: modular communications for tangible and embedded interfaces

Bladed Tiles is a modular hardware toolkit for building tangible and embedded interface devices. It includes “function blades” and “interaction tiles,” which can provide a flexible, inexpensive, open-ended platform for constructing a wide variety of tangible and embedded interfaces. In this paper, we propose Communication Blades. These are a class of electronic modules with varied computational capabilities for interfacing devices built using bladed tiles toolkit and also for interfacing embedded devices as adapters with external communication networks. These blades provide flexibility by offering the ability to select between different communication technologies and connectivity by providing devices with interoperability over different communication mediums. Furthermore, the modular blade architecture allows different types of communication blades to be plugged in on demand. This reduces the need for development and knowledge of communication protocols by the developers, thus abstracting the underlying complexity. My research work includes studying and designing various communication blades i.e. Serial, USB, Bluetooth and Gumstix. It also includes prototyping, testing and implementing the communication blades

The s-mote: a versatile heterogeneous multi-radio platform for wireless sensor networks applications

This paper presents a novel architecture and its implementation for a versatile, miniaturised mote which can communicate concurrently using a variety of combinations of ISM bands, has increased processing capability, and interoperability with mainstream GSM technology. All these features are integrated in a small form factor platform. The platform can have many configurations which could satisfy a variety of applications’ constraints. To the best of our knowledge, it is the first integrated platform of this type reported in the literature. The proposed platform opens the way for enhanced levels of Quality of Service (QoS), with respect to reliability, availability and latency, in addition to facilitating interoperability and power reduction compared to existing platforms. The small form factor also allows potential of integration with other mobile platforms including smart phones

Innovative energy-efficient wireless sensor network applications and MAC sub-layer protocols employing RTS-CTS with packet concatenation

of energy-efficiency as well as the number of available applications. As a consequence there are challenges that need to be tackled for the future generation of WSNs. The research work from this Ph.D. thesis has involved the actual development of innovative WSN applications contributing to different research projects. In the Smart-Clothing project contributions have been given in the development of a Wireless Body Area Network (WBAN) to monitor the foetal movements of a pregnant woman in the last four weeks of pregnancy. The creation of an automatic wireless measurement system for remotely monitoring concrete structures was an contribution for the INSYSM project. This was accomplished by using an IEEE 802.15.4 network enabling for remotely monitoring the temperature and humidity within civil engineering structures. In the framework of the PROENEGY-WSN project contributions have been given in the identification the spectrum opportunities for Radio Frequency (RF) energy harvesting through power density measurements from 350 MHz to 3 GHz. The design of the circuits to harvest RF energy and the requirements needed for creating a WBAN with electromagnetic energy harvesting and Cognitive Radio (CR) capabilities have also been addressed. A performance evaluation of the state-of-the art of the hardware WSN platforms has also been addressed. This is explained by the fact that, even by using optimized Medium Access Control (MAC) protocols, if the WSNs platforms do not allow for minimizing the energy consumption in the idle and sleeping states, energy efficiency and long network lifetime will not be achieved. The research also involved the development of new innovative mechanisms that tries and solves overhead, one of the fundamental reasons for the IEEE 802.15.4 standard MAC inefficiency. In particular, this Ph.D. thesis proposes an IEEE 802.15.4 MAC layer performance enhancement by employing RTS/CTS combined with packet concatenation. The results have shown that the use of the RTS/CTS mechanism improves channel efficiency by decreasing the deferral time before transmitting a data packet. In addition, the Sensor Block Acknowledgment MAC (SBACK-MAC) protocol has been proposed that allows the aggregation of several acknowledgment responses in one special Block Acknowledgment (BACK) Response packet. Two different solutions are considered. The first one considers the SBACK-MAC protocol in the presence of BACK Request (concatenation) while the second one considers the SBACK-MAC in the absence of BACK Request (piggyback). The proposed solutions address a distributed scenario with single-destination and single-rate frame aggregation. The throughput and delay performance is mathematically derived under both ideal conditions (a channel environment with no transmission errors) and non ideal conditions (a channel environment with transmission errors). An analytical model is proposed, capable of taking into account the retransmission delays and the maximum number of backoff stages. The simulation results successfully validate our analytical model. For more than 7 TX (aggregated packets) all the MAC sub-layer protocols employing RTS/CTS with packet concatenation allows for the optimization of channel use in WSNs, v8-48 % improvement in the maximum average throughput and minimum average delay, and decrease energy consumption

Design Experiences on Single and Multi Radio Systems in Wireless Embedded Platforms

The progress of radio technology has made several flavors of radio available on the market.Wireless sensor network platform designers have used these radios to build a variety of platforms. Withnew applications and different types of radios on wireless sensing nodes, it is often hard to interconnectdifferent types of networks. Hence, often additional radios have to be integrated onto existingplatforms or new platforms have to be built. Additionally, the energy consumption of these nodes have to be optimized to meetlifetime requirements of years without recharging.In this thesis, we address two issues of single and multi radio platform designfor wireless sensor network applications - engineering issues and energy optimization.We present a set of guiding principles from our design experiences while building 3 real life applications,namely asset tracking, burglar tracking and finally in-situ psychophysiological stress monitoring of human subjects in behavioral studies.In the asset tracking application, we present our design of a tag node that can be hidden inside valuable personal assets such asprinters or sofas in a home. If these items are stolen, a city wide anchor node infrastructure networkwould track them throughout the city. We also present our design for the anchor node.In the burglar tracking application, we present the design of tag nodes and the issueswe faced while integrating it with a GSM radio. Finally, we discuss our experiencesin designing a bridge node, that connects body worn physiological sensorsto a Bluetooth enabled mobile smartphone. We present the software framework that acts as middleware toconnect to the bridge, parse the sensor data, and send it to higher layers of the softwareframework.We describe 2 energy optimization schemes that are used in the Asset Tracking and the Burglar Tracking applications, that enhance the lifetime of the individual applications manifold.In the asset tracking application,we design a grouping scheme that helps increase reliability of detection of the tag nodes at theanchor nodes while reducing the energy consumption of the group of tag nodes travelling together.We achieve an increase of 5 times improvement in lifetime of the entire group. In the Burglar Tracking application, weuse sensing to determine when to turn the GSM radio on and transmit data by differentiatingturns and lane changes. This helps us reduce the number of times the GSM radio is woken up, thereby increasing thelifetime of the tag node while it is being tracked. This adds 8 minutes of trackablelifetime to the burglar tracking tag node. We conclude this thesis by observing the futuretrends of platform design and radio evolution

MOBILITY CONTROL IN WIRELESS SENSOR NETWORK

Wireless sensor networks (WSNs) have become one of the most important topics in wireless communication during the last decade. WSNs integrates many different technologies such as in hardware, software, data fusion, and applications. Hence, WSNs has received recently special research activities. WSNs have so many applications in different areas such as health-care systems, monitoring and control systems, rescue systems, and military applications. Since WSNs are usually deployed with large numbers of nodes in wide areas, they should be reliable, inexpensive, with very low power consumption, and with high redundancy to preserve the life-time of the whole network. In this M.Sc. thesis we consider one extremely important research topic in WSNs which is the mobility control. The mobility control is analyzed theoretically as well as with extensive simulations. In the simulation scenarios, static sensor nodes are first randomly deployed to the decided area. Then a reference trajectory for the mobile node is created based on the observed point phenomena, and the network guides the mobile node to move along the trajectory. A simulation platform called PiccSIM is used to simulate the scenarios. It is developed by the Communication and Control Engineering Groups at Helsinki University of Technology (TKK). The obtained results from these simulations are discussed and analyzed. This work opens the doors for more real applications in this area in the nearby future.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Towards a Realistic Energy Model for Wireless Sensor Networks

Energy consumption is one of the most critical protocol properties in a wireless sensor network. Therefore, a precise energy model is required for the evaluation of protocols. In addition to evaluation, an energy model can also be used for on-line energy accounting. After processing user queries, nodes aware of the energy model can send an energy bill towards the network\u27s sink. This allows the user to adjust future queries to be more energy efficient. The contribution of this paper is twofold: First, a theoretical energy model based on simple finite automata is presented. This model can be used for on-line accounting, simulation and generation of a-priori knowledge. Second, the proposed theoretical model is backed up by practical measurements using a new measurement device called SNMD that also offers management functions for sensor-net testbeds. Therewith, output of the theoretical model can be compared to and justified by real-world measurements

Energy-aware Gossip Protocol for Wireless Sensor Networks

Dissertação de mestrado em Engenharia InformáticaIn Wireless Sensor Networks (WSNs), typically composed of nodes with resource constraints, leveraging efficient processes is crucial to enhance the network longevity and consequently the sustainability in ultra-dense and heterogeneous environments, such as smart cities. Epidemic algorithms are usually efficient in delivering packets to a sink or to all it’s peers but have poor energy efficiency due to the amount of packet redundancy. Directional algorithms, such as Minimum Cost Forward Algorithm (MCFA) or Directed Diffusion, yield high energy efficiency but fail to handle mobile environments, and have poor network coverage. This work proposes a new epidemic algorithm that uses the current energy state of the network to create a topology that is cyclically updated, fault tolerant, whilst being able to handle the challenges of a static or mobile heterogeneous network. Depending on the application, tuning in the protocol settings can be made to prioritise desired characteristics. The proposed protocol has a small computational footprint and the required memory is proportional not to the size of the network, but to the number of neighbours of a node, enabling high scalability. The proposed protocol was tested, using a ESP8266 as an energy model reference, in a simulated environment with ad-hoc wireless nodes. It was implemented at the application level with UDP sockets, and resulted in a highly energy efficient protocol, capable of leveraging extended network longevity with different static or mobile topologies, with results comparable to a static directional algorithm in delivery efficiency.Em Redes de Sensores sem Fios (RSF), tipicamente compostas por nós com recursos lim-itados, alavancar processos eficientes é crucial para aumentar o tempo de vida da rede e consequentemente a sustentabilidade em ambientes heterogéneos e ultra densos, como cidades inteligentes por exemplo. Algoritmos epidêmicos são geralmente eficientes em en-tregar pacotes para um sink ou para todos os nós da rede, no entanto têm baixa eficiência energética devido a alta taxa de duplicação de pacotes. Algoritmos direcionais, como o MCFA ou de Difusão Direta, rendem alta eficiência energética mas não conseguem lidar com ambientes móveis, e alcançam baixa cobertura da rede. Este trabalho propõe um novo protocolo epidêmico que faz uso do estado energético atual da rede para criar uma topologia que por sua vez atualizada ciclicamente, tolerante a falhas, ao mesmo tempo que é capaz de lidar com os desafios de uma rede heterogênea estática ou móvel. A depender da aplicação, ajustes podem ser feitos às configurações do protocolo para que o mesmo priorize determinadas características. O protocolo proposto tem um pequeno impacto computacional e a memória requerida é proporcional somente à quantidade de vizinhos do nó, não ao tamanho da rede inteira, permitindo assim alta escalabilidade. O algoritmo proposto foi testado fazendo uso do modelo energético de uma ESP8266, em um ambiente simulado com uma rede sem fios ad-hoc. Foi implementado à nível aplicacional com sockets UDP, e resultou em um protocol energeticamente eficiente, capaz de disponibilizar alta longevidade da rede mesmo com diferentes topologias estáticas ou móveis com resultados comparáveis à um protocolo direcional em termos de eficiência na entrega de pacotes

Enabling technologies for distributed body sensor networks

Low Power Wireless Sensor Networks, Preventative Healthcare and Pervasive Systems are set to provide long-term continuous monitoring, diagnosis and care for patients in the next few years. Distributed forms of these networks are investigated from a holistic point of view. Individual components of these systems including: sensors, software and hardware implementations are investigated and analysed. Novel sensors are developed for low power capturing of Body Sensor Network (BSN) information to enable long term use. Software frameworks are designed to enable these technologies to run on low power nodes as well as enabling them to perform evaluation of their data before transmission into the network. An architecture is designed to enable task distribution to intensive processing from low power nodes. Two forms of distributed BSNs are also developed: a horizontal network and a vertical network. It is shown that using these two types of networks enables information and task distribution allowing low power sensing nodes to evaluate information before transmission. These systems have the opportunity to revolutionalise expensive acute episodic care systems of today, but are not currently being implemented or investigated to the extent that they could. The technological barriers to entry are addressed in this thesis with the investigation and evaluation of distributed body sensor networks. It is shown that horizontal networks can distribute information efficiently, while vertical networks can distribute processing efficiently

Development of Wireless Sensor Network Technology for Soil Property Monitoring

In the first part of this thesis, we designed and developed a soil property monitoring system with two generation evolutions. Soil property parameter data including soil moisture, soil electrical conductivity and near-surface soil temperature were collected from using two kinds of sensors embedded in four different depths as 50.8, 152.4, 304.8 and 609.6mm underground. A hybrid sensor network (HSN) conceptual system module including in-field wireless sensor network, cellular network and the Internet was put forward and realized for transmitting in-field data to the lab infrastructure. Results from the first part of the thesis indicated that wireless sensor network technologies had considerable advantages in field data collection and transmission over the traditional invasive methods. System quality of service testing results as: the average packet delivery rate and in-field data error rate were 95.05% and 0% until day of test while the averaged valid data rate was above 97% in general for each node. In the second part of this thesis, outdoor as well as off-line laboratory statistical experiments were carried out for analyzing impacts of impact factors as plant height, antenna gain, transmitter & receiver height, and separation distance to in-field radio propagation and modeling radio wave path loss to make the communication performance predictable. The experiments were divided into three blocks by two plant heights as 0.05m and 0.4m. Three widely used path loss models as COST-Hata, free space and plane earth models were included for verifying their applicability for in-field scenarios. Multi-variable linear regression was applied for relating the path loss to the impact factors. Results from the second part of the thesis indicated that the blocking criteria selection was proper and the Fresnel clearance dominated the in-field radio wave attenuation while the influence of reflection patterns was non-ignorable. R2 for the four regressed path loss prediction model was 0.822, 0.810, 0.843, and 0.899, respectively. By comparing measured path loss to predicted ones using general and regressed models, COST-Hata model yielded the highest difference, free space model yielded the second highest difference, and specific regressed models generated the least difference in most cases. A threshold of 70m was obtained for reliable communication in the worst cases of our experimental scenarios.Biosystems and Agricultural Engineerin