Denna rapport beskriver ett kandidatarbete som genomfördes i kursen TDDD96 Kandidatprojekt i programvaruutveckling år 2023. Den produkt som framställdes under projektet är en webbapplikation för felsökning av informationsskyltar via Bluetooth och arbetet genomfördes med en agil arbetsmetodik. Syftet med denna rapport är att förklara hur projektgruppen arbetade under kandidatprojektet och skapade värde för kunden, samt att belysa både tekniska lärdomar och andra erfarenheter som projektgruppen fick under arbetet. Rapporten beskriver överförbar kunskap gällande projektarbeten respektive utveckling med Bluetooth som kan vara användbar i framtida projekt. För att dokumentera erfarenheter, skapa värde för kunden och förbättra arbetsprocessen under projektet genomfördes mätningar, testning, informationssamling, prototypframställning och utvärderingsmöten i form av retrospektiv och en muddy-cards-utvärdering.  Projektgruppen har utvecklat en webbapplikation som använder sig av Web Bluetooth API för att hämta en godtyckligt stor fil givet att användaren skriver in dess sökväg i felsökningsapplikationen. För att skicka filer av godtycklig storlek delas de upp i paket som alla skickas separat. En av de främsta fördelarna med det använda API:t är att ingen nedladdning eller installation krävs men en stor nackdel är att det inte är kompatibelt med alla webbläsare. Vidare har erfarenheter såsom för- och nackdelar med mobbprogrammering, vikten av olika sprintlängder, antal scrum-möten samt uppdelning av arbete dokumenterats. Under projektet har det även visats att en systemanatomi hjälper utvecklare att dela in och se kopplingar mellan olika delar i ett system samt att kundmöten är centrala för att säkerställa att en beställd produkt är av värde för kunden.

The decreasing cost of web-enabled smart devices utilizing embedded processors, sensors, and wireless communication hardware have created an optimal ecosystem for the Internet of Things (IoT). IEEE802.15.4, IEEE802.11ah, WirelessHART, ZigBee Smart Energy, Bluetooth (BT), and Bluetooth Low Energy (BLE) are amongst the most commonly used wireless standards for IoT systems. Each of these standards has tradeoffs concerning power consumption, range of communication, network formation, security, reliability, and ease of implementation. The most widely used standards for IoT are Bluetooth, BLE, and Zigbee. This paper discusses the vulnerabilities in the implementation of the PHY and link layers of BLE. The link layer defines the scheme for establishing a link between two devices. Scanning devices are able to establish communication with other devices that are sending advertising packets. These advertising packets are sent out in a deterministic fashion. The advertising channels for BLE, specified by the PHY layer, are Channels 37, 38, and 39, at center frequencies 2.402, 2.426, and 2.480 GHz, respectively. This scheme for establishing a connection seems to introduce an unintentional gap in the security of the protocol. Creating and transmitting tones with center frequencies corresponding to those of the advertising channels, a victim BLE device will be unable to establish a connection with another BLE device. Jamming a mesh network of BLE devices relies on this same concept. The proposed jamming system is an inexpensive one which utilizes the following hardware. Three individual synthesizers, a microcontroller (MCU), Wilkinson power combiner, power amplifier, and antenna, integrated on a single PCB, are used to transmit a 3-tone signal. Due to the unprecedented nature of the COVID-19 pandemic, necessary adjustments were made to the jammer system design. In the first modified jamming scheme, a single synthesizer evaluation board, power amplifier, and antenna, are used to transmit jamming tones in the form of a frequency hop. Limitations of the frequency hop approach necessitated a second modified scheme. In this second scheme a synthesizer and two Software Defined Radios (SDR), connected to a personal computer, continuously generate three individual jamming tones. The proposed jammer and the modified ones all classify as constant jammers as the transmission of jamming signals is continuous. Both modified jamming schemes are tested. The results of jamming using the second modified scheme validate the objective of simultaneous jamming of the advertising channels of BLE devices. The success of the modified scheme enables the original goal of creating a relatively inexpensive custom PCB for BLE advertising channel jamming. By exploiting the weakness of the BLE protocol, the hope is to have the governing body for Bluetooth, Bluetooth Special Interest Group (SIG), improve security for the future releases of BLE.

This thesis aims at evaluating a proposed interferometry Angle of Arrival method for Bluetooth Low Energy and investigating the feasibility of using it together with current technology in a keyless entry access control solution. The current technology is an evaluation kit from Texas Instrument that is used together with various types of antennae arranged in arrays. An in-depth look at it revealed that it does not implement the proposed Angle of Arrival method for Bluetooth Low Energy but the deviations are minor. Results obtained from tests with delay lines show enough accuracy for a keyless entry access control solution. However, none of the tested antenna types do. The work concludes that current technology cannot be used as a keyless entry access control solution due to strong antenna dependencies. Future work is thus proposed to be done on antenna development. / Detta arbete syftar till att utvärdera en förslagen interferometri Angle of Arrival-metod för Bluetooth Low Energy samt undersöka möjligheten att använda den tillsammans med nuvarande tekniken i nyckellös åtkomstkontroll. Den nuvarande tekniken är ett utvärderingspaket från Texas Instrument som används tillsammans med olika typer av antenner. En utförlig undersökning av tekniken avslöjade att den inte implementerar den föreslagna Angle of Arrival-metod för Bluetooth Low Energy men avvikelserna är minimala. Resultat som erhållits från tester med fördröjningslinjer visar tillräckligt noggrannhet för nyckellös åtkomstkontroll. Men ingen av de testade antenntyperna gör det. Arbetet drar slutsatsen att den nuvarande tekniken inte kan användas som nyckellös åtkomstkontroll på grund av starka antennberoende. Framtida arbete föreslås således att fokusera på antennutveckling.

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Wireless technology is used daily across the globe. A very common wireless technology is Bluetooth. The Bluetooth technology exists everywhere, from cars to mobile phones and even kitchen appliances. Recently, Bluetooth Low Energy has added support for another physical layer, LE 2M PHY. This physical layer is supposed to be faster and more energy efficient than its predecessor, LE 1M PHY, with a decrease in range. Because of this new physical layer, Bluetooth Low Energy can now compete with Bluetooth Classic during data transmission, in both speed and energy efficiency. This thesis aims to find the breaking point where Bluetooth Low Energy becomes less energy efficient than Bluetooth Classic, in relation to bit rate speed and total amount of bytes sent. Before experiments were conducted, multiple iterations of an artifact had to be done to end up with an artifact that provides valid and reliable data. The experiments were then conducted by changing the bit rate speed and sending different amounts of bytes. The results from the experiments show that Bluetooth Classic is practically both faster and more energy efficient with its fastest modulation than Bluetooth Low Energy is with LE 2M PHY enabled, even though this should not be the case theoretically. Bluetooth Classic is overall more energy efficient than Bluetooth Low Energy and thus the conclusion of this study is that no breaking points between the two technologies exist.

A wireless sensor node (WSN) system, capable of sensing animal motion and transmitting motion data wirelessly, is an effective and efficient way to monitor pigs' activity. However, the raw sensor data sampling and transmission consumes lots of power such that WSNs' battery have to be frequently charged or replaced. The proposed work solves this issue through WSN edge computing solution, in which a Random Forest Classifier (RFC) is trained and implemented into WSNs. The implementation of RFC on WSNs does not save power, but the RFC predicts animal behavior such that WSNs can adaptively adjust the data sampling frequency to reduce power consumption. In addition, WSNs can transmit less data by sending RFC predictions instead of raw sensor data to save power. The proposed RFC classifies common animal activities: eating, drinking, laying, standing, and walking with a F-1 score of 93%. The WSN power consumption is reduced by 25% with edge computing intelligence, compare to WSN power that samples and transmits raw sensor data periodically at 10 Hz. / Master of Science / A wireless sensor node (WSN) system that detects animal movement and wirelessly transmits this data is a valuable tool for monitoring pigs' activity. However, the process of sampling and transmitting raw sensor data consumes a significant amount of power, leading to frequent recharging or replacement of WSN batteries. To address this issue, our proposed solution integrates edge computing into WSNs, utilizing a Random Forest Classifier (RFC). The RFC is trained and deployed within the WSNs to predict animal behavior, allowing for adaptive adjustment of data sampling frequency to reduce power consumption. Additionally, by transmitting RFC predictions instead of raw sensor data, WSNs can conserve power by transmitting less data. Our RFC can accurately classify common animal activities, such as eating, drinking, laying, standing, and walking, achieving an F-1 score of 93%. With the integration of edge computing intelligence, WSN power consumption is reduced by 25% compared to traditional WSNs that periodically sample and transmit raw sensor data at 10 Hz.

In recent years, wireless audio devices have become a staple of our everyday lives. The growing demands for low-latency and multi-speaker wireless audio streaming have led to the adoption of various technologies such as Wi-Fi and a combination of Bluetooth and other proprietary radio links. Since Bluetooth has a fairly limited range and a peer-to-peer topology, it is unsuitable for streaming audio directly to multiple devices. This is where Wi-Fi based systems gained popularity, owing to their high bandwidth and flexible architecture to support audio streaming to multiple devices over larger distances. This however, comes at the cost of high power consumption and non-deterministic packet latency. With the advent of Bluetooth LE Audio, we now have a framework for broadcast audio streaming over the power efficient Bluetooth LE standard. This thesis explores the performance characteristics of Bluetooth LE Audio systems and draws a comparison with the current landscape of Wi-Fi based audio solutions. This performance data is further used to develop a proof-of-concept LE Audio repeater system, which could help solve the range limitation that has plagued Bluetooth devices in the past. For the specific system developed, a power consumption of around 14 mA was obtained, which is a fraction of the power required by equivalent Wi-Fi based systems. We also obtained a deterministic and relatively low latency of 34 ms and were able to demonstrate the feasibility of implementing repeater nodes using Bluetooth LE Audio. / Under de senaste åren har trådlösa ljudenheter blivit en stapelvara i vår vardag. De växande kraven på trådlöst strömmande ljud med låg tidsfördröjning och flera högtalare har resulterat i olika tekniker såsom WiFi och en kombination av Bluetooth och tillverkarspecifika radiolösningar. Eftersom Bluetooth har begränsningar både i räckvidd och topologi, är den olämplig för direktströmmande ljud till flera enheter. Därför har WiFi-baserade system blivit populära, med sin högre bandbredd och flexibla arkitektur som stöder strömmande ljud till flera enheter över större avstånd. Detta kommer dock på bekostnad av hög strömförbrukning och icke-deterministisk tidsfördröjning. Med tillkomsten av Bluetooth LE Audio, har vi nu ett ramverk för att strömma ljud över den strömsnåla Bluetooth LE-standarden. Denna avhandling utforskar prestandaegenskaper hos Bluetooth LE Audio-system och gör en jämförelse med nuvarande typer av WiFi-baserade ljudlösningar. Resultatet används vidare för att utveckla en prototyp till repeater-system för LE Audio, som kan hjälpa till att öka räckvidden som har hittills har varit en begränsande faktor hos Bluetooth-enheter. För den utvecklade prototypen erhölls en strömförbrukning på ca 14 mA, vilket är en bråkdel av den effekt som krävs av motsvarande WiFi-baserade system. Vi fick också en deterministisk och relativt låg fördröjning på 34 ms och kunde därmed visa att det är genomförbart att implementera repeater-noder för Bluetooth LE Audio.

This thesis compares and evaluates the accuracy of two RSSI-based tri-lateration methods in an indoor setting, implementing either Wi-Fi andBluetooth Low Energy (BLE) while using commercially available hardware.The purpose of evaluation is part of the long-term vision of improving thesafety of workers in adverse environments such as factories, by providing awearable Indoor Positioning System where other systems like GPS are notsuitable due to signal obstruction. Within a confined space replicating in-tended real-world conditions in terms of signal attenuation and adversity,30 consecutive measurements of signal strength readings (RSSI) to threereference nodes were collected at 10 randomized sample positions, andwas repeated across 5 tests. The accuracy of trilateration was evaluatedusing an averaged Root Mean Square Error (RMSE) over the five tests. Itwas observed that RSSI using Wi-Fi achieved better accuracy of predictingthe actual position within the testing environment than signal-strength us-ing BLE, with Wi-Fi and BLE achieving an accuracy of 0.88 and 1.85 metersrespectively. However, because of the power efficiency of BLE it is a viablecandidate for a future low-cost and device-based Indoor Localization Sys-tem to potentially be used and worn by workers. The results while alignedwith similar existing literature, infer what a low-cost indoor positioningsystem might achieve. Future research with the goal of developing suchsolutions could benefit from implementing both Wi-Fi and BLE as the basisof signal strength trilateration.

Qu’il s’agisse de suivre des patients à domicile, ou de prévenir l’isolement ou la vulnérabilité de personnes âgées, les systèmes de suivi et d'assistance électroniques qui émergent offrent des opportunités sans précédents. L’enjeu est considérable, et on assiste à un développement technologique important qui permet désormais aux particuliers ou aux établissements hospitaliers ou médico-sociaux d’assurer le diagnostic, la prévention, le contrôle, voire le traitement de patients à distance (mesures de paramètres physiologiques, administration de médicaments, détection de chutes, etc.). Ce suivi à distance est en particulier devenu possible et performant avec l’avènement des objets connectés. On peut ainsi envisager d’exploiter un réseau de capteurs embarqué sur un patient pour mesurer à distance et en temps réel la température, le rythme cardiaque ou la tension artérielle d’un patient. Les données sont transmises (et/ou stockées) au praticien pour réaliser le diagnostic et définir les traitements. Pour autant la conception optimale (choix des technologies de transmission, de stockage, etc.) ainsi que la problématique de la gestion d’énergie constituent des verrous à leur adoption. Le travail proposé dans cette thèse consiste donc à développer un outil d’aide à la conception de réseaux de capteurs médicaux communicants embarqués sur la personne. Il s’agit en particulier de fournir une information sur la faisabilité au plus tôt dans le cycle de conception, et garantir l’obtention d’un circuit « correcte par construction ». L’accent est porté sur la maîtrise (voire la réduction) de la consommation d’énergie Dans ce sens, une simulation fiable et précise permet de contrôler, dès le début du flot de conception, la consommation en énergie du réseau. Elle assure par la suite une meilleure gestion de l’énergie disponible et éventuellement une autonomie plus importante. L’outil, centré sur l’optimisation de la consommation d’énergie, est implémenté dans un environnement Matlab. Basé sur une modélisation de la consommation en énergie d’un nœud de capteur, il se veut générique aussi bien que précis. Il assure une implémentation simple de nouveaux composants à partir de fiches techniques. Ces composants sont construits sous la forme de blocs réutilisables permettant ainsi à l’utilisateur de créer sa propre librairie. En plus de l’estimation de la consommation, cet outil met en œuvre des algorithmes d’optimisation pour guider l’utilisateur vers une conception qui respecte les contraintes énergétiques et médicales de l’application (choix de composants, choix de source d’énergie, configuration du réseau, etc.). Une application est proposée d’abord au niveau d’un nœud de capteur de température corporelle communiquant par Bluetooth Low Energy. Ce même nœud est ensuite placé au sein d’un réseau de capteurs pour la surveillance de cinq paramètres physiologiques différents. Une validation expérimentale des résultats de simulation est également réalisée. / Whether it is to monitor patients at home, or to prevent the isolation and vulnerability of the elderly, the emerging electronic monitoring and assistance systems offer new opportunities. The technological development we have witnessed allows individuals, hospitals, or medical aid organizations to provide the diagnosis, prevention, control or even treatment of patients outside of conventional clinical settings (measurements of physiological parameters, drug administration, fall detection, etc.).Recent developments in connected objects made efficient remote patient monitoring possible. In other words, we are able to use a network of wearable or implantable sensors to remotely obtain real time measurements of a patient’s vital signs (temperature, heart rate, blood pressure, etc.). Data is transmitted (and / or stored) to medical personnel who are able to perform diagnosis and define treatments accordingly. An optimal design (transmission protocols, data storage, etc.) and energy management are the bottlenecks involved in the implementation of such systems. This work proposes to develop a tool to help in the design of medical sensor networks. It aims to provide information regarding feasibility during the early stages of the design thus ensuring that a "well-constructed" circuit is obtained. The emphasis is on the control (or even reduction) of energy consumption. In this regard, an efficient energy consumption simulation at the beginning of the design flow would enable the user to decide on system parameters. This will ensure an optimal management of the available energy and eventually a longer network lifetime. The proposed tool is centered on the optimization of the energy consumption using Matlab environment. It is built over a model of the energy consumption of wireless sensor nodes. It is intended to be generic and accurate. In fact, it enables fast creation of new component description based on the datasheets. These components are reusable thus producing a growing database. In addition to energy consumption estimation, the tool uses optimization routines to guide the user through an energy aware design (picking energy sources, components, network configuration, etc.) that complies with medical requirements. An application to a single Bluetooth Low Energy body temperature sensor is first proposed. The same sensor is then included in a physiological sensor network. A physical implementation is used in order to compare the results obtained through simulation with practical measurements.