Examensarbetet genomfördes tillsammans med företaget Rol Ergo. Syftet med studien var att analysera Zigbee 3.0 och Bluetooth Low Energy 5.2 och deras lämplighet i tidskritiska system genom att studera latensen och förhållandet mellan signalstyrkan och avståndet mellan de två kommunikationsprodukter. Datainsamlingen genomfördes med en experimentell studie och utifrån kunskap som framskaffats har ett visst antal bestämda experiment utförts för att svara på frågeställningarna som ställs.  Datainsamlingen visar att både maxlatensen och typiska latensen hos Zigbee är lägre än maxlatens och typiska latens för Bluetooth Low Energy. Datainsamlingen för signalstyrkan visar att Bluetooth Low Energys signalstyrka blir mer påverkad av avståndet mellan kommunikationsprodukterna än vad Zigbees blir. Det visar även att den optimala förhållande mellan signalstyrkan och avståndet hos Zigbee är bättre än hos Bluetooth Low Energy.  Slutsatsen av arbetet är att Zigbee är mer lämpad för tidkritiska system än Bluetooth Low Energy då låg latensen prioriteras. Zigbee är även mer lämpad då lång distansen prioriteras men då bör signalstyrkan ligga runt -50dBm. Bluetooth Low Energy är dock mer lämpad då lång distans inte prioriteras och signalstyrkan inte behöver vara utmärkt för att kunna kommunicera.  Begränsningarna för arbetet är att Bluetooth Low Energy och Zigbee endast har prövats på utvecklingskortet nRF5340 DK.  På grund av den begränsade tiden så har endast ett antal bestämda experiment som har föreslagits av rådgivare på Rol Ergo utförts. / The thesis has been conducted together with  Rol Ergo company. The purpose of this study is to analyse Zigbee 3.0 and Bluetooth Low Energy 5.2 and their suitability for time-critical systems, by studying latency and the relations between signal strength and distance between two communication products. The data collection was completed by an experimental study. By using knowledge that has been collected for the study, sets of experiments will be performed to answer the research questions.  Results of the collected data indicate that both the maximum latency and the typical latency for Zigbee is significantly lower than for Bluetooth Low Energy. The collected data for signal strength shows that the signal strength for Bluetooth Low Energy is more affected by distance between the communication product, than Zigbee’s is. It also shows that the optimal ratio between signal strength and distance for Zigbee is better than for Bluetooth Low Energy. The conclusion of the study shows Zigbee to be a more suitable for time-critical systems compared to Bluetooth Low Energy when low latency is being prioritized. Zigbee is also more suitable for time-critical systems when long distance is being prioritized, however the signal strength must then be around -50 dBm. Bluetooth Low Energy is more suitable when long distance is not the priority, and the signal strength does not have to be excellent to be able to communicate.  The limitations for this thesis are that Bluetooth Low Energy and Zigbee will only be tested on the nRF5349 Development Kit. given limited time, only a certain of experiments, whereas some have been suggested by advisors from Rol Ergo, has been carried out.

Elektrodiagram eller EKG används inom sjukvården för att mäta hjärtats elektriska aktivitet med hjälp av flera elektroder som placeras ut på kroppen. Från mätningarna kan indikationer på hjärtsjukdomar och störningar i hjärtrytm upptäckas och sedan behandlas. Hjärt- och kärl-sjukdomar är den vanligaste dödsorsaken i Sverige och behovet av EKG undersökningar är stort. Vanligtvis är EKG-apparaterna stora, otympliga och begränsade till sjukhus då de är komplicerade och dyra. Linköpings universitets forskningsgrupp tillsammans med flera examensarbeten har då tagit fram en prototyp på en kompakt och portabel EKG. Den portabla EKG-apparaten kopplas med en sele som är integrerad med elektroder och ska brukas av främst kvinnor, då utbudet av användarvänliga EKG:s till kvinnor är litet. Den tidigare portabla EKG:en är uppbyggd av två moduler, EKG-modulen och Nordic Thingy52. EKG-modulen konstruerad på ett specialanpassat kretskort som utför den faktiska mätningen av elektroderna och uträkningar. Den är sedan ihopkopplad med Thingy52 som ansvarar för den trådlösa kommunikationen till andra enheter via Bluetooth Low Energy eller BLE som det också kallas. BLE-modulen som innefattade Thingy52 och den modifierade källkoden från tidigare arbeten, klarade av viss trådlös kommunikation men ansågs vara förlångsam och klarade inte av kontinuerlig dataöverföring. Från de tidigare arbetena uppkom då frågeställningar om det var möjligt att vidareutveckla den tidigare BLE-modulen genom att förbättra dataöverföring och införa fler funktioner. De mest väsentliga önskemål var att optimera modulens dataöverföring till att bli kontinuerlig, införa funktionalitet för att spara mätvärden som en typ av backup och introducera ett enklare digitalt filter för att filtrera bort brus och störningar på mätvärdena. Utöver detta skulle även ett kompaktare och mindre kretskort till BLE-modulen tas fram som skulle ersätta Thingy52. Projektet började med att införskaffa kunskap och förståelse om hur befintliga och tillkommande funktioner samt tjänster fungerar samt hur de ska implementeras. Val om vilka komponenter och utvecklingsmiljöer som skulle användas under projektet fastställdes. Valen resulterade i att fortsätta med tidigare System-on-chip, SoC nRF52832 från Nordic Semiconductor som Thingy52 är utformad runt. Detta ledde till att befintliga utvecklingskort kunde användas och kretsschema från Thingy52 kunde återanvändas till det nya kretsschemat. Innan det eget skapade kretskortet kunde beställas och testas behövdes verifiering av att den valda SoC klarade av kontinuerlig dataöverföring. Detta kunde utföras på utvecklingskort nRF52 SDK med samma typ av SoC. Verifieringen av dataöverföringen var mer tidskrävande än vad som hade räknats med och tyvärr blev det inte tid att beställa kretskortet och kunde inte testas i praktiken. Ett kretsschema utfördes ändå som har mindre dimensioner än Thingy52 och innehåller de önskade delarna. Under utveckling av BLE-funktionen valdes det att använda Nordic:s nya utvecklingsmiljö som förenklade programmering av avancerade funktioner, till exempel BLE. Valet av att byta utvecklingsmiljö resulterade dock i att tidigare programmeringskod som hanterade konfigurering och dataöverföring med EKG-modulen, behövdes konverteras om till ett nytt operativsystem efter att Nordic bytt till operativsystemet Zypher. Detta gav i följd att funktioner och bibliotek inte stödes eller inte fanns. Efter detta flyttades fokuset till att implementera och integrera lagringsfunktionen med BLE- och EKG-funktionerna. Multitrådning infördes för att kunna utföra och optimera BLE-modulens funktioner. Tidsbrist gjorde att endast platshållare för framtida implementering av digitala filter kunde utföras. Utifrån de testresultaten över BLE-modulen är det även svårt att garantera att SoC hinner utföra filtrering av mätdata under det redan begränsade tidsintervallet. Efter en del problem och många tester resulterade examensarbetet slutligen i ett kompakt kretsschema som skulle kunna ersätta Thingy52. En BLE-modul som kan utföra dataöverföring med viss kontinuerlighet och samtidigt lagra mätdata till ett SD-kort utan att påverka kommunikationen med EKG-modulen eller användargränssnittet. Slutprodukten har även många möjligheter att utökas i framtida arbeten. / Electrocardiography or ECG is used in healthcare to measure the electrical activity of the heart using several electrodes that are placed on the body. From the measurements, indications of heart diseases and heart rhythm disorders can be detected and then treated. Cardiovascular disease is the most common cause of death in Sweden and the need for ECG examinations is great. Usually the ECG devices are large, awkward, and limited to hospitals as they are complicated and expensive. Linköping University's research group together with several bachelor thesis projects has developed a prototype of a compact and portable ECG. The portable ECG device is connected to a bra that is integrated with electrodes and should be used mainly by women, as the range of user-friendly ECGs for women is small. The previously portable ECG is made up of two modules, the ECG module, and the Nordic Thingy52. The ECG module is designed on a specially adapted circuit board that performs the actual measurement of the electrodes and calculations. It is then paired with Thingy52 which is responsible for the wireless communication to other devices via Bluetooth Low Energy or BLE as it is also called. The BLE module, which included Thingy52 and the modified source code from previous work, managed some wireless communication but was considered too slow and could not handle continuous data transfer. From the previous work questions arose as to whether it was possible to further develop the previous BLE module by improving data transfer and introducing more features. The most desired features were to optimize the module's data transfer to become continuous, implement functionality to save measured values as a type of backup and implement a simple digital filter to filter out noise and disturbances of the measured values. In addition to this, a more compact and smaller circuit board for the BLE module would also be developed that would replace the Thingy52. The project began with acquiring knowledge and understanding of how existing and additional functions or services work and how they should be implemented. Choices about which components and development environments would be used during the project were determined. The choice resulted in continuing with the previous System-on-chip, SoC nRF52832 from Nordic Semiconductor around which Thingy52 is designed. As a result, existing development boards could be used and the circuit diagram from Thingy52 could be reused for the new circuit diagram. Before the self-created circuit board could be ordered and tested, verification was needed to determine that the selected SoC was capable of continuous data transfer. This could be done on development card nRF52 SDK with the same type of SoC. The verification of the data transfer was more time consuming than had been expected and unfortunately there was no time to order the circuit board and therefore could not be tested in practice. A circuit diagram was nevertheless performed which has smaller dimensions than Thingy52 and contains the desired parts. During the development of the BLE function, it was chosen to use Nordic's new development environment as it simplified programming of advanced functions, like BLE. The choice to change the development environment, however, resulted in the previous programming code, which handled configuration and data transfer with the ECG module, having to be converted to a new operating system after Nordic switched to the Zypher operating system. As a result, functions and libraries were not supported or did not exist. After this, the focus shifted to implementing and integrating the storage function with the BLE and ECG functions. The multithreading tool was introduced to perform and optimize the functions of the BLE module. Lack of time meant that only placeholders for future implementation of digital filters could be performed. Based on the test results over the BLE module, it is also difficult to guarantee that the SoC has time to perform filtering of measurement data during the already limited time interval. After some problems and many tests, the bachelor thesis project finally resulted in a compact circuit that could replace Thingy52. Also, a BLE module that can perform data transfer with some continuity and at the same time store measurement data to a SD card without affecting the communication with the ECG module or the user interface. The end product also has many opportunities to be expanded in future work.

The rapid enhancement of low-power short range wireless connectivity has been a driving factor of the pervasive adoption of Internet-of-Things (IoT). However, the lack of universal standard for such technologies causes compatibility issues and slows down innovation. The Bluetooth Low Energy (BLE) protocol has become the leading protocol that is most likely to be adopted as the standard over other compatible technologies and thus has to be studied thoroughly and all characteristics evaluated. Several major enhancements were introduced in the release of BLE 5 which makes the technology instantly more attractive in wider range of use cases than before. These enhancements bring additional complexity into the BLE architecture while allowing for more flexibility and configuration varieties to optimize each use case. This thesis attempts to evaluate the benefits of new features in BLE for a specific device developed by Tritech Technologies and the possibility of utilizing several features to improve wireless performance. Additionally, the technology architecture is deeply studied, challenges in implementation identified and operational characteristics measured. Results of the literature review discusses how the scalability of BLE has significantly improved, new features provide more flexibility making the technology more attractive for all IoT and finally recommends further work in order to have a single standard when operating low-powered wireless communication. Moreover, test results of power consumption, possible range and throughput are summarized showing that the new features can bring significant benefits to certain products but massive drawbacks might occur in form of power consumed if not carefully implemented. To point out some notable test results acquired in this project, double the energy utility was achieved by utilizing high speed physical layer (PHY) in high throughput operation that reached data transfer rate of 1.37 MB/s. Using long range PHY with coding scheme of eight symbols per bit reached roughly 1 km range in Line-of-Sight (LoS) and improvement from about half-house to nearly full-house coverage. Furthermore, a method of dynamically switching PHYs was implemented and concluded not suitable for such an application due to high added power consumption. / Den snabba förbättringen av trådlös kommunikation med låg energiförbrukning har präglat utvecklingen av Internet-of-Things (IoT). Bristen på en universell standard för sådan teknik orsakar kompatibilitetsproblem och kan hämma innovation. Protokollet för Bluetooth Low Energy (BLE) har kommit att bli det ledande protokoll som förmodligen kommer att antas som standarden över andra kompatibla teknologier och måste därför granskas noggrant och alla dess egenskaper utvärderas. Flera anmärkningsvärda förbättringar introducerades i utgåvan av BLE 5 vilket omedelbart gör tekniken mer attraktiv i ett större användningsområde än tidigare. Dessa förbättringar ger ytterligare komplexitet i BLE-arkitekturen, samtidigt som detta möjliggör mer flexibilitet och konfigurationsvarianter för att optimera varje användningsfall.Denna rapport försöker att utvärdera fördelarna med nya funktioner i BLE för en specifik produkt som utvecklats av Tritech Technologies och möjligheten att utnyttja flera funktioner för att förbättra den trådlösa anslutningen. Protokollarkitekturen är dessutom granskad, utmaningar i genomförandet identifierade och operativa egenskaper uppmätta. Resultaten från litteraturöversikten diskuterar hur skalbarheten hos BLE har förbättrats avsevärt, hur nya funktioner bidrar till flexibilitet vilket gör tekniken mer attraktiv för all typ av IoT och slutligen rekommenderar vidare arbete för att kunna uppnå en standard för trådlös kommunikation med låg energiförbrukning. Dessutom sammanfattas testresultatet av strömförbrukning, möjlig räckvidd och datahastighet, vilket visar att de nya funktionerna kan ge betydande fördelar för vissa produkter men att nackdelar kan förekomma i form av strömförbrukning om den inte är noggrant genomförd. BLE 5 jämfördes med tidigare versioner och resultaten från denna jämförelse visade på att fördubblad energy utility kunde uppnås genom att använda ett Physical Layer (PHY) med höghastighetsegenskaper och dataöverföringshastighet på 1.37 MB/s. Då ett PHY med lång räckvidd och datakodning på åtta symboler per bit användes kunde en räckvidd på cirka 1 km siktlinje uppnås och en förbättring kunde ses i en tvåplansvilla där täckningen ökat från cirka halva byggnaden till nästan hela byggnaden. Dessutom utvecklades en metod för att dynamiskt byta PHY under användning, och slutsatsen visade att denna metod ej är lämplig för den produkt som utreddes på grund av den ökade energiförbrukningen som då uppstod.

Development of technical and methodological support has been identified as a key area for future research and development within the search and rescue (SAR) of missing persons in Sweden. Previous studies have demonstrated the feasibility of using Wi-Fi signals to locate a missing person, and also developed hardware and software for SAR systems based around Unmanned Aerial Vehicles (UAV). This thesis empirically studies the actual transmission behaviour of three non-connected smartphones over Wi-Fi and Bluetooth Low Energy (BLE), under the assumption that a missing person could be carrying a smartphone with them. Furthermore, the thesis studies the range of relatively low-cost off-the-shelf Wi-Fi and BLE devices in a “best-case” scenario with free line-of-sight and a slightly elevated transmitter. Finally, the thesis studies how antennas and other factors impact range. The results show that all of the tested smartphones transmit so called Wi-Fi probe packets when Wi-Fi is enabled. Though, these probes are, in most cases, transmitted during short events separated by intervals of 5 to 9 minutes, depending on the smartphone. Furthermore, in most cases only a few packets are transmitted in each event. The interval lengths and scarce packets imply significant limitations to the usability of Wi-Fi in SAR. BLE broadcast transmissions, on the other hand, require that some kind of advertising service is enabled, but are transmitted at least every 10.5 seconds, due to the strict regulation in the Bluetooth standard. This was also demonstrated with the studied iPhone that continuously transmitted BLE packets every two seconds. Roughly 60 % of the smartphones in use in Sweden today are Apple devices, thus a significant portion of all the smartphones in use are likely to be detectable via BLE within brief time intervals. In the tested “best-case” scenario with free line-of-sight and a slightly elevated transmitter, at least 80 % of the transmitted Wi-Fi probes are detected up to 500-600 meters with a maximum range, with sparsely detected packets, of up to about 700 meters. Correspondingly, at least 80 % of the BLE advertisements are detected up to 60-110 meters with occasional packets detected up to a maximum range of approximately 210 meters. However, the ranges for both Wi-Fi and BLE are highly dependent on the receiving device. In addition to the receiver device and standard, it is found that the transmission power and antenna directivity of the transmitter have a potentially substantial impact on the range with a possible combined difference in directed transmitted power of up to 49 dB. This corresponds to the difference between a strong signal and no detected signal at all. In summary, there are clear differences between the properties of BLE and Wi-Fi, both in terms of range and how different devices transmit broadcast packets (transmission behaviour), resulting in both having advantages and disadvantages in SAR applications. There are also a number of factors on the transmitter and receiver devices that could have considerable impact on the possibility of detecting a device. Concludingly, both BLE and Wi-Fi could fill a role in SAR of missing persons, but both also have major drawbacks that are severely limiting their possible use. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

The work presented herein explores the ability of Ultra High Frequency Radio Frequency (UHF RF) devices, specifically (Radio Frequency Identification) RFID passive tags and Bluetooth Low Energy (BLE) to be used as tools to locate items of interest inside a building. Localization Systems based on these technologies are commercially available, but have failed to be widely adopted due to significant drawbacks in the accuracy and reliability of state of the art systems. It is the goal of this work to address that issue by identifying and potentially improving upon localization algorithms. The work presented here breaks the process of localization into distance estimations and trilateration algorithms to use those estimations to determine a 2D location. Distance estimations are the largest error source in trilateration. Several methods are proposed to improve speed and accuracy of measurements using additional information from frequency variations and phase angle information. Adding information from the characteristic signature of multipath signals allowed for a significant reduction in distance estimation error for both BLE and RFID which was quantified using neural network optimization techniques. The resulting error reduction algorithm was generalizable to completely new environments with very different multipath behavior and was a significant contribution of this work. Another significant contribution of this work is the experimental comparison of trilateration algorithms, which tested new and existing methods of trilateration for accuracy in a controlled environment using the same data sets. Several new or improved methods of triangulation are presented as well as traditional methods from the literature in the analysis. The Antenna Pattern Method represents a new way of compensating for the antenna radiation pattern and its potential impact on signal strength, which is also an important contribution of this effort. The performance of each algorithm for multiple types of inputs are compared and the resulting error matrix allows a potential system designer to select the best option given the particular system constraints.

To know your whereabouts is important and sometimes exact position is the determinant of success or not. Since the launch of the USA made Global Positioning System (GPS) in the late 1970s, global tracking has been available both for military and civilian use. Today, satellite based systems like the American GPS, European Galileo and the Russian GLONASS are the standard for basically any navigation or location application. However these systems are limited by the fact that they must have connection with multiple satellites in order to work. This means that satellite dependent systems are very limited in indoor environments. Despite this, there is no standard for indoor positioning systems (IPSs) even close to the satellite dependent systems when it regards distribution and accessibility for use where satellite dependent systems are limited or not working. However, this new age of connectivity provides a number of options for positioning indoors. There are some systems available, but very few of them provide good enough accuracy. This Master thesis evaluates different options for indoor positioning using technologies that are available in smart devices and smart phones, such as Wi-Fi and Bluetooth, and focuses on indoor positioning systems that can provide high accuracy. The current state of the technologies and the possible future for them, considering rising need and interest in indoor positioning systems are covered in this thesis. A selection of technologies and approaches are explored, tested in conditions designed for this purpose and evaluated to highlight their differences in approach, accuracy and usability. In order to achieve the goals of this thesis, a hybrid method of experimental research design and system development is selected as the main research method. The hybrid method is focused on experimental research, and is used to investigate if the accuracy of the positioning data can be affected and improved by tuning independent variables in an IPS. To be able to do this, an application for smart devices, such as android smartphones, is developed. The application developed is the heart of the conceptual crossover IPS (CCIPS), which is named Locantis, that is being developed and used in the experimental stages of this investigation. It is also used to test the hypothesis that a CCIPS could be a valid contender for replacing the established IPSs. The observations show how the accuracy and precision of the location data is affected by change to independent variables in an IPS and how well a CCIPS can meet real time requirement’s. The main conclusion is that changes to independent variables have greater impact on the precision than the accuracy for location data in an IPS and that a CCIPS in many cases are the sensible choice of IPS. / Att veta var du befinner dig är viktigt och ibland är exakt position avgörande för framgång. Sedan lanseringen av amerikanska Global Positioning System (GPS) i slutet av 1970 har global navigation varit tillgängliga för både militärt och civilt bruk. Idag är satellitbaserade system, som det amerikanska GPS, europeiska Galileo och det ryska GLONASS, standard för i princip alla navigering eller platsinformation. Men dessa system är begränsade av det faktum att de måste ha kontakt med flera satelliter för att fungera. Detta innebär att satellitberoende system är mycket begränsad i inomhusmiljöer. Trots detta finns det ingen standard för inomhus positioneringssystem (IPSS) som kan mäta sig med de satellitberoende systemen när det gäller distribution och tillgänglighet. Men denna nya generationens kommunikation ger ett antal alternativ för positionering inomhus. Det finns IPS tillgängliga idag, men väldigt få av dem kan tillhandahålla en hög noggrannhet på positioneringen. Detta examensarbete utvärderar olika alternativ för inomhuspositionering med teknologier som är tillgängliga i smarta enheter och smarta telefoner, som Wi-Fi och Bluetooth, fokus ligger på inomhus positioneringssystem som kan ge hög noggrannhet. Det aktuella läget för dessa teknologier och dess möjliga framtid, med tanke på stigande behov och intresse av inomhus positioneringssystem, behandlas i detta examensarbete. Ett urval av teknologier och metoder utforskas, testas under förhållanden utformade för detta ändamål, och utvärderas för att lyfta fram sina skillnader i tillvägagångssätt, noggrannhet och användbarhet. För att uppnå målen i detta examensarbete har en hybrid metod för experimentell designforskning och systemutveckling valts som huvudsaklig forskningsmetod. Hybridmetoden fokuserar på experimentell forskning och används för att undersöka om positioneringsdatas noggrannhet kan påverkas och förbättras genom att förändra oberoende variabler i ett IPS. För att kunna göra detta har en applikation för smarta enheter, så som Android, utvecklats. Applikationen som utvecklats är hjärtat i det konceptuella kombinations inomhuspositioneringssystem Locantis som utvecklas och används i det experimentella stadiet i denna undersökning. Den används också för att testa hypotesen att en CCIPS kunde vara en giltig kandidat för att ersätta den etablerade IPSer. Observationerna visa hur noggrannhet och precision av positioneringsdata påverkas av förändring på oberoende variabler i ett IPS och hur väl ett CCIPS kan uppfylla realtidskravet talet. Huvudslutsatsen är att förändringar på oberoende variabler har större inverkan på precision än noggrannheten för lokaliseringsuppgifter i en IPS och att ett CCIPS i många fall är det klokt val av IPS.

Orientador: Prof. Dr. Ivan Roberto Santana Casella / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2016. / Atualmente existem diversos padrões de redes sem fio destinados ao monitoramento de sensores em aplicações de redes sem fio. O Bluetooth Low Energy (BLE) e o Zigbee são duas tecnologias em destaques que estão sendo amplamente empregadas em Smart Grids e Internet of Things (IOT) e foram desenvolvidas para o envio rápido de pequenos pacotes de dados em baixa latência com suporte a elevados números de nós operando em baixo consumo de energia. A degradação da potência de um sinal de rádio transmitido por dispositivos Bluetooth Low Energy e Zigbee pode ser ocasionada pela existência de objetos (paredes, portas, janelas e vegetações) que interferem na livre propagação do sinal eletromagnético. O objetivo deste trabalho foi analisar e comparar, através de uma modelagem computacional, os impactos da atenuação do sinal de rádio de redes sem fio BLE e Zigbee operando em ambiente indoor. Foram medidos os valores da potência do sinal recebido, relação sinal-ruído, taxa de dados e taxa de erro de bit estimada para diferentes fatores de perda de percurso e considerado o efeito de Shadowing.A modelagem computacional foi desenvolvida com auxílio do software OPNET Modeler e contemplou algoritmos que simulam as camadas PHY, MAC e enlace do BLE e do Zigbee, que permitiu analisar o comportamento das redes sem fio durante as trocas de pacotes de dados entre os dispositivos móveis. Além das simulações computacionais, foram feitos experimentos práticos com redes sem fio BLE e Zigbee localizadas em ambiente indoor em zona urbana. Os resultados das medições em campo foram comparadas e configuradas no modelagem computacional. Desta forma, foram criados modelos computacionais do BLE e Zigbee que descrevem parcialmente os mesmos comportamentos das redes sem fio ensaiadas nos experimentos práticos, o que tornou os resultados das simulações da modelagem computacional muito mais realistas. Através destes novos modelos computacionais, foi possível medir, comparar e analisar o desempenho das redes sem fio BLE e Zigbee em ambiente indoor. e da taxa de dados e provoca um aumento de BER à medida que o receptor se distância do transmissor em uma rede de dispositivos BLE e a adição do Shadowing tornou os resultados da modelagem computacional muito mais realista. Além das análises, este trabalho contribuiu com detalhes do desenvolvimento da modelagem computacional do BLE e Zigbee que foi realizado.Os resultados das simulações demonstraram que o aumento do fator de perda de percurso causou uma redução significativa da potência de recebimento e da taxa de dados e provoca um aumento de BER à medida que o receptor se distância do transmissor em uma rede de dispositivos BLE e a adição do Shadowing tornou os resultados da modelagem computacional muito mais realista. Além das análises, este trabalho contribuiu com detalhes do desenvolvimento da modelagem computacional do BLE e Zigbee que foi realizado. / Currently there are different standards of wireless networks for the sensors monitoring in wireless networking applications. Bluetooth Low Energy (BLE) and Zigbee are two technologies widely used in Smart Grids and Internet of Things (IOT) and were developed for the fast sending of small data packets at low latency with high numbers of nodes operating in low energy consumption. The degradation of the power of a radio signal transmitted by a BLE and Zigbee devices can be caused by the existence of objects, walls, doors, windows and vegetation, that interfere with the free propagation of electromagnetic signals. The objective of this work was to analyze and compare, through computer simulations, the radio signal attenuation of wireless networks BLE and Zigbee when operating in indoor environment. The value of the received signal strength, signal to noise ratio, data rate and bit error rate estimated for different path loss factors were measured and considered the effect of shadowing. The computer simulations was developed with the help of OPNET Modeler software, which included algorithms that simulate the PHY, MAC and Link Layer of the BLE and Zigbee, which allowed analyzing the behavior of wireless networks for the exchange of data packets between the mobile devices. In addition to the computer simulations were made practical experiments with wireless networks BLE and Zigbee located in indoor environment in urban areas. The results of field measurements were compared and set in computational modeling. Thus they were created computer models of BLE and Zigbee that describe partially the same behaviors of the tested wireless networks in the field via practical experiments, which made the simulation results of computer modeling more realistic. Through these new computer models were possible to measure, compare and analyze the performance of wireless networks BLE and Zigbee in indoor environment. The results of computer simulations have shown that increasing the path loss factor caused a significant reduction in received power and data rate and causes an increased BER when the receiver is away from the transmitter in a network BLE devices and adding the shadowing in computer simulations became more realistic results. In addition, this work contributed to the development details of computational modeling of BLE and Zigbee.

For every year the importance of lowering energy consumptionof our devices gets more important. Wireless devicesget smaller which leads to the fact that they need smallerbatteries than earlier versions. At the same time the customersstill have high requirements on the battery time. So what followsis that new technologies are needed to meet the customerrequirements by lowering the energy consumption for the devicesto maintain the same battery time as earlier.Today it is very common that these wireless devices makesuse of the wireless Bluetooth protocol in order to communicatewith other devices, for example with a mobile application.Bluetooth is in many cases more energy consuming thannecessary. In this report the wireless Bluetooth Low Energyprotocol will be tested and evaluated to see if the energy consumptionof a battery driven ground station for weather measurementscan be reduced.

abstract: The Internet of Things has conjured up a storm in the technology world by providing novel methods to connect, exchange, aggregate, and monitor data across a system of inter-related devices and entities. Of the myriad technologies that aid in the functioning of these IoT devices, Bluetooth Low Energy also known as BLE plays a major role in establishing inter-connectivity amongst these devices. This thesis aims to provide a background on BLE, the type of attacks that could occur in an IoT setting, the possible defenses that are available to prevent the occurrence of such attacks, and a discussion on the research trends that hold great promise in presenting seamless solutions to integrate IoT devices across different industry verticals. / Dissertation/Thesis / Masters Thesis Computer Science 2017

abstract: Wearable technology has brought in a rapid shift in the areas of healthcare and lifestyle management. The recent development and usage of wearable devices like smart watches has created significant impact in areas like fitness management, exercise tracking, sleep quality assessment and early diagnosis of diseases like asthma, sleep apnea etc. This thesis is dedicated to the development of wearable systems and algorithms to fulfill unmet needs in the area of cardiorespiratory monitoring. First, a pneumotach based flow sensing technique has been developed and integrated into a face mask for respiratory profile tracking. Algorithms have been developed to convert the pressure profile into respiratory flow rate profile. Gyroscope-based correction is used to remove motion artifacts that arise from daily activities. By using Principal Component Analysis, the follow-up work established a unique respiratory signature for each subject based on the flow profile and lung parameters computed using the wearable mask system. Next, wristwatch devices to track transcutaneous gases like oxygen (TcO2) and carbon dioxide (TcCO2), and oximetry (SpO2) have been developed. Two chemical sensing approaches have been explored. In the first approach, miniaturized low-cost commercial sensors have been integrated into the wristwatch for transcutaneous gas sensing. In the second approach, CMOS camera-based colorimetric sensors are integrated into the wristwatch, where a part of camera frame is used for photoplethysmography while the remaining part tracks the optical signal from colorimetric sensors. Finally, the wireless connectivity using Bluetooth Low Energy (BLE) in wearable systems has been explored and a data transmission protocol between wearables and host for reliable transfer has been developed. To improve the transmission reliability, the host is designed to use queue-based re-request routine to notify the wearable device of the missing packets that should be re-transmitted. This approach avoids the issue of host dependent packet losses and ensures that all the necessary information is received. The works in this thesis have provided technical solutions to address challenges in wearable technologies, ranging from chemical sensing, flow sensing, data analysis, to wireless data transmission. These works have demonstrated transformation of traditional bench-top medical equipment into non-invasive, unobtrusive, ergonomic & stand-alone healthcare devices. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2020