Ultra Low Power Communication Protocols for UWB Impulse Radio Wireless Sensor Networks

This thesis evaluates the potential of Ultra Wideband Impulse Radio for wireless sensor network applications. Wireless sensor networks are collections of small electronic devices composed of one or more sensors to acquire information on their environment, an energy source (typically a battery), a microcontroller to control the measurements, process the information and communicate with its peers, and a radio transceiver to enable these communications. They are used to regularly collect information within their deployment area, often for very long periods of time (up to several years). The large number of devices often considered, as well as the long deployment durations, makes any manual intervention complex and costly. Therefore, these networks must self-configure, and automatically adapt to changes in their electromagnetic environment (channel variations, interferers) and network topology modifications: some nodes may run out of energy, or suffer from a hardware failure. Ultra Wideband Impulse Radio is a novel wireless technology that, thanks to its extremely large bandwidth, is more robust to frequency dependent propagation effects. Its impulsional nature makes it robust to multipath fading, as the short duration of the pulses leads most multipath components to arrive isolated. This technology should also enable high precision ranging through time of flight measurements, and operate at ultra low power levels. The main challenge is to design a system that reaches the same or higher degree of energy savings as existing narrowband systems considering all the protocol layers. As these radios are not yet widely available, the first part of this thesis presents Maximum Pulse Amplitude Estimation, a novel approach to symbol-level modeling of UWB-IR systems that enabled us to implement the first network simulator of devices compatible with the UWB physical layer of the IEEE 802.15.4A standard for wireless sensor networks. In the second part of this thesis, WideMac, a novel ultra low power MAC protocol specifically designed for UWB-IR devices is presented. It uses asynchronous duty cycling of the radio transceiver to minimize the power consumption, combined with periodic beacon emissions so that devices can learn each other's wake-up patterns and exchange packets. After an analytical study of the protocol, the network simulation tool presented in the first part of the thesis is used to evaluate the performance of WideMac in a medical body area network application. It is compared to two narrowband and an FM-UWB solutions. The protocol stack parameters are optimized for each solution, and it is observed that WideMac combined to UWB-IR is a credible technology for such applications. Similar simulations, considering this time a static multi-hop network are performed. It is found that WideMac and UWB-IR perform as well as a mature and highly optimized narrowband solution (based on the WiseMAC ULP MAC protocol), despite the lack of clear channel assessment functionality on the UWB radio. The last part of this thesis studies analytically a dual mode MAC protocol named WideMac-High Availability. It combines the Ultra Low PowerWideMac with the higher performance Aloha protocol, so that ultra low power consumption and hence long deployment times can be combined with high performance low latency communications when required by the application. The potential of this scheme is quantified, and it is proposed to adapt it to narrowband radio transceivers by combining WiseMAC and CSMA under the name WiseMAC-HA

Dual protocol performance using WiFi and ZigBee for industrial WLAN

The purpose of this thesis is to study the performance of a WNCS based on utilizing IEEE 802.15.4 and IEEE 802.11 in meeting industrial requirements as well as the extent of improvement on the network level in terms of latency and interference tolerance when using the two different protocols, namely WiFi and ZigBee, in parallel. The study evaluates the optimum performance of WNCS that utilizes only IEEE 802.15.4 protocol (which ZigBee is based on) without modifications as an alternative that is low cost and low power compared to other wireless technologies. The study also evaluates the optimum performance of WNCS that utilizes only the IEEE 802.11 protocol (WiFi) without modifications as a high bit network. OMNeT++ simulations are used to measure the end-to-end delay and packet loss from the sensors to the controller and from the controller to the actuators. It is demonstrated that the measured delay of the proposed WNCS including all types of transmission, encapsulation, de-capsulation, queuing and propagation, meet real-time control network requirements while guaranteeing correct packet reception with no packet loss. Moreover, it is shown that the demonstrated performance of the proposed WNCS operating redundantly on both networks in parallel is significantly superior to a WNCS operating on either a totally wireless ZigBee or WiFi network individually in terms of measured delay and interference tolerance. This proposed WNCS demonstrates the combined advantages of both the IEEE 802.15.4 protocol (which ZigBee is based on) without modifications being low cost and low power compared to other wireless technologies as well the advantages of the IEEE 802.11 protocol (WiFi) being increased bit rate and higher immunity to interference. All results presented in this study were based on a 95% confidence analysis

A Multi-Hop 6LoWPAN Wireless Sensor Network for Waste Management Optimization

In the first part of this Thesis several Wireless Sensor Network technologies, including the ones based on the IEEE 802.15.4 Protocol Standard like ZigBee, 6LoWPAN and Ultra Wide Band, as well as other technologies based on other protocol standards like Z-Wave, Bluetooth and Dash7, are analyzed with respect to relevance and suitability with the Waste Management Outsmart European FP7 Project. A particular attention is given to the parameters which characterize a Large Scale WSN for Smart Cities, due to the amount of sensors involved and to the practical application requested by the project. Secondly, a prototype of sensor network is proposed: an Operative System named Contiki is chosen for its portability on different hardware platforms, its Open Source license, for the use of the 6LoW-PAN protocol and for the implementation of the new RPL routing protocol. The Operative System is described in detail, with a special focus on the uIPv6 TCP/IP stack and RPL implementation. With regard to this innovative routing proto col designed specifically for Low Power Lossy Networks, chapter 4 describes in detail how the network topology is organized as a Directed Acyclic Graph, what is an RPL Instance and how downward and upward routes are constructed and maintained. With the use of several AVR Atmel modules mounting the Contiki OS a real WSN is created and, with an Ultrasonic Sensor, the filling level of a waste basket prototype is periodically detected and transmitted through a multi-hop wireless network to a sink nodeope

Modélisation et simulation de réseaux locaux et personnels sans fil : intégration des couches PHY et MAC

Dans ce travail nous nous intéressons à la modélisation des couches MAC et PHY dans le cadre des réseaux sans fil à faible, portée. Il présente les techniques de modélisation utilisées pour l'intégration des couches MAC-PHYs (Medium Access Control and Physical layer) de type IR-UWB (Impulse Radio Ultra Wideband) d'une part, et des nouvelles techniques de transmission à 60GHz incluant le beamforming d'autre part, dans le simulateur GloMoSim/QualNet. La modélisation de IR-UWB est basée sur la prise en compte directe des collisions d'impulsions et de l'interférence multi-utilisateur au niveau de la couche PHY par l'introduction du concept de séquences de réception et la notion d'orthogonalité en réception. L'architecture de modélisation proposée est basée sur l'utilisation d'une matrice d'interférence, elle a été développée en deux étapes : une première modélisation basée sur des trains d'impulsions uniformément espacées et une deuxième modélisation plus complète prenant en compte l'utilisation des séquences de sauts aléatoires également appelés séquences de time hopping. L'évaluation de performances de cette partie est basée sur une application typique des réseaux de capteurs dans le cadre d'une application de détection d'intrusion sur une surface protégée. La modélisation à 60 GHz à pour but la prise en compte des nouvelles techniques d'amélioration du débit, notamment l'agrégation et le beamforming. La prise en compte du beamforming est basée sur la définition, des diagrammes de rayonnement des antennes ainsi que de l'interface MAC-PHY/Antenne. La modélisation des deux protocoles de beamforming définis dans le standard 802.15.3c est également effectuée. L'évaluation de performances de cette partie est basée sur un système de distribution de contenu multimédia.In this work, we focus on physical and medium access control layer modeling and simulation for short range wireless communication. In particular, the modeling of the Impulse Radio Ultra Wide Band technique for wireless sensor networks and the high data rate communication modeling which uses millimeter wave and beamforming. The first part deals with the modeling of Impulse Radio Ultra Wide Band. The proposed model takes into account the pulse collision induced by multiple concurrent transmissions at the physical layer which is also called multi user interference. This aspect is accurately introduced thanks to the concept of reception time hopping sequences of concurrent reception and their orthogonality. The simulation architecture is built using two models: the first model is based on a uniformly distributed pulse train and the second model, more complete, takes into account variable time hopping sequences. The performance evaluation of this part is based on a typical wireless sensor networks application, in which sensor nodes are scattered on a particular area to detect and report intrusion events to a base station. The second part deals with the modeling of high data rate communication using millimeter wave. The targeted goal of millimeter wave transmission is to increase the data rate using some novel techniques: beamforming and data aggregation. Beamforming is modeled on the so-called codebook beamforming defined as the new beamforming technique for high data rate wireless communication standards. A methodology is developed to take into account the radiation pattern defined by the codebook indexes. For each index the gain of the directional antenna is computed for each direction. This is used in the simulation model physical layer to determine the directional antenna gain in a particular direction during the propagation stage. The defined protocols for sector level and beam level training defined in the 802.15.3c draft are also modeled. The performance evaluation of this part is based on a multimedia distribution system

Ultra-low power IoT applications: from transducers to wireless protocols

This dissertation aims to explore Internet of Things (IoT) sensor nodes in various application scenarios with different design requirements. The research provides a comprehensive exploration of all the IoT layers composing an advanced device, from transducers to on-board processing, through low power hardware schemes and wireless protocols for wide area networks. Nowadays, spreading and massive utilization of wireless sensor nodes pushes research and industries to overcome the main limitations of such constrained devices, aiming to make them easily deployable at a lower cost. Significant challenges involve the battery lifetime that directly affects the device operativity and the wireless communication bandwidth. Factors that commonly contrast the system scalability and the energy per bit, as well as the maximum coverage. This thesis aims to serve as a reference and guideline document for future IoT projects, where results are structured following a conventional development pipeline. They usually consider communication standards and sensing as project requirements and low power operation as a necessity. A detailed overview of five leading IoT wireless protocols, together with custom solutions to overcome the throughput limitations and decrease the power consumption, are some of the topic discussed. Low power hardware engineering in multiple applications is also introduced, especially focusing on improving the trade-off between energy, functionality, and on-board processing capabilities. To enhance these features and to provide a bottom-top overview of an IoT sensor node, an innovative and low-cost transducer for structural health monitoring is presented. Lastly, the high-performance computing at the extreme edge of the IoT framework is addressed, with special attention to image processing algorithms running on state of the art RISC-V architecture. As a specific deployment scenario, an OpenCV-based stack, together with a convolutional neural network, is assessed on the octa-core PULP SoC

Filtered multi-carrier modulations for industrial wireless communications based on cognitive radio

Doktoretza-tesi honetako helburu nagusia, hari gabeko komunikazio industrialetarako fidagarritasun maila onargarria eman dezakeen maila fisikoko modulazio bat aurkitzea da. Eremu industrialetako radio bidezko kanaletan ematen diren komunikazioetarako baldintza bereziki aurkakoak direla eta, helburu hori lortzea benetako erronkatzat jo liteke. Gainera, modulazio horrek \Radio Cognitiva" deritzoten teknikekin bateragarria izan beharra dauka, hauek hari gabeko komunikazioen fidagarritasuna hobetzeko gaitasuna baitute. Bibliografian oinarrituz, gaur egungo baliabideekin hari gabeko komunikazio industrial kasu ugariri konponbidea emateko aukera badela ondoriozta genezake, baina ez kasu guztiei ordea. Hari gabeko kanalen egoera bereziki aurkakoa denerako eta komunikazio sistemek denbora muga bereziki zorrotzak bete behar dituztenerako, ezta erantzun nahikoa ona eman lezakeen hari gabeko komunikazio sistema industrialik bibliografia zientifikoan. Hori dela eta, doktoretza tesi honetan, \Radio Cognitiva" delakoa eta 5G-rako aurreikusita dauden filtro bankuetan oinarrituriko modulazio multigarraiatzaileak bezalako teknologia hasiberrietara jotzen dugu, aurrez aipaturiko arazoari konponbide berriak bilatu nahian. Bibliografian dauden filtro bankuetan oinarrituriko modulazio multi-garraiatzaileak aztertu eta ondoren beraien egokitasuna ebaluatzen dugu, kanal dispertsiboen aurkako sendotasuna eta \Radio Cognitiva" teknikekin izan lezaketen bateragarritasuna irizpide hartuz. Ebaluaketa horretan oinarrituz, doktoretza-tesi honetan \Radio Cognitiva" teknikekin bateragarria den WCP-COQAM proposatzen dugu modulazio industrial gisa. Modulazio teknika berau erakusteaz gain, bibliografian eskuragarri ez dauden WCP-COQAM-rentzat sinkronizazio eta kanal estimazio teknikak ere aurkezten ditugu.El objetivo principal de esta tesis doctoral consiste en encontrar una modulación de capa física capaz de proporcionar robustez y fiabilidad suficientes a sistemas de comunicaciones inalámbricas industriales. Esto supone un desafío, dadas las adversas condiciones del canal inalámbrico propias de entornos industriales. Además, dicha modulación debería presentar una alta compatibilidad con las técnicas de Radio Cognitiva, debido al potencial de éstas para mejorar la fiabilidad de las comunicaciones inalámbricas. Basándonos en la bibliografía, concluimos que las soluciones presentes en el estado del arte actual cubren una amplia variedad de escenarios dentro de las comunicaciones inalámbricas industriales, pero no todas. Para los escenarios con canales altamente dispersivos y requerimientos de tiempo especialmente estrictos, no existe ninguna solución en la industria ni dentro de la bibliografía científica. En esta tesis doctoral nos centramos en tecnologías incipientes como la Radio Cognitiva y las modulaciones multi-portadora con bancos de filtros para 5G para tratar de buscar nuevas soluciones al problema anteriormente descrito. Por lo tanto, analizamos algunas de las técnicas multi-portadora con bancos de filtros presentes en la bibliografía científica y las evaluamos basándonos en su robustez frente a canales altamente dispersivos y su compatibilidad con la Radio Cognitiva. Basándonos en dicha evaluación, proponemosWCP-COQAM como posible candidata a modulación industrial compatible con Radio Cognitiva. Además de la propia técnica de modulación, presentamos métodos de sincronización y estimación de canal para la misma que no se encuentran presentes en el estado del arte.The main goal of this doctoral thesis is to find a physical layer modulation able to provide high enough robustness and reliability levels for wireless industrial communications systems. Considering the harsh wireless channel conditions of industrial environments, that goal implies a considerable challenge. Besides, this modulation should be highly compatible with Cognitive Radio techniques, due to their potential to improve the reliability of wireless communications. Based on the bibliography, we conclude that the existent solutions in the current state of the art cover a wide range of wireless industrial communications scenarios, but not all of them. There is no solution, neither in the industry nor in the scientific bibliography, for those scenarios involving highly dispersive wireless channels and particularly stringent timeliness requirements. In this doctoral thesis, we focus on upcoming technologies such as Cognitive Radio and multi-carrier modulations based on filter banks for 5G, in order to search new solutions for the aforementioned problem. Therefore, we analyse some of the multi-carrier modulations based on filter banks of the scientific bibliography and we evaluate them in terms of robustness against highly dispersive channels and in terms of compatibility with Cognitive Radio. In this doctoral thesis we propose the modulation WCP-COQAM as possible candidate for industrial wireless modulation and compatible with Cognitive Radio. In addition to the modulation technique itself, we also introduce some synchronization and channel estimation techniques which are not present in the state of the art

Cognitive Security Framework For Heterogeneous Sensor Network Using Swarm Intelligence

Rapid development of sensor technology has led to applications ranging from academic to military in a short time span. These tiny sensors are deployed in environments where security for data or hardware cannot be guaranteed. Due to resource constraints, traditional security schemes cannot be directly applied. Unfortunately, due to minimal or no communication security schemes, the data, link and the sensor node can be easily tampered by intruder attacks. This dissertation presents a security framework applied to a sensor network that can be managed by a cohesive sensor manager. A simple framework that can support security based on situation assessment is best suited for chaotic and harsh environments. The objective of this research is designing an evolutionary algorithm with controllable parameters to solve existing and new security threats in a heterogeneous communication network. An in-depth analysis of the different threats and the security measures applied considering the resource constrained network is explored. Any framework works best, if the correlated or orthogonal performance parameters are carefully considered based on system goals and functions. Hence, a trade-off between the different performance parameters based on weights from partially ordered sets is applied to satisfy application specific requirements and security measures. The proposed novel framework controls heterogeneous sensor network requirements,and balance the resources optimally and efficiently while communicating securely using a multi-objection function. In addition, the framework can measure the affect of single or combined denial of service attacks and also predict new attacks under both cooperative and non-cooperative sensor nodes. The cognitive intuition of the framework is evaluated under different simulated real time scenarios such as Health-care monitoring, Emergency Responder, VANET, Biometric security access system, and Battlefield monitoring. The proposed three-tiered Cognitive Security Framework is capable of performing situation assessment and performs the appropriate security measures to maintain reliability and security of the system. The first tier of the proposed framework, a crosslayer cognitive security protocol defends the communication link between nodes during denial-of-Service attacks by re-routing data through secure nodes. The cognitive nature of the protocol balances resources and security making optimal decisions to obtain reachable and reliable solutions. The versatility and robustness of the protocol is justified by the results obtained in simulating health-care and emergency responder applications under Sybil and Wormhole attacks. The protocol considers metrics from each layer of the network model to obtain an optimal and feasible resource efficient solution. In the second tier, the emergent behavior of the protocol is further extended to mine information from the nodes to defend the network against denial-of-service attack using Bayesian models. The jammer attack is considered the most vulnerable attack, and therefore simulated vehicular ad-hoc network is experimented with varied types of jammer. Classification of the jammer under various attack scenarios is formulated to predict the genuineness of the attacks on the sensor nodes using receiver operating characteristics. In addition to detecting the jammer attack, a simple technique of locating the jammer under cooperative nodes is implemented. This feature enables the network in isolating the jammer or the reputation of node is affected, thus removing the malicious node from participating in future routes. Finally, a intrusion detection system using `bait\u27 architecture is analyzed where resources is traded-off for the sake of security due to sensitivity of the application. The architecture strategically enables ant agents to detect and track the intruders threateningthe network. The proposed framework is evaluated based on accuracy and speed of intrusion detection before the network is compromised. This process of detecting the intrusion earlier helps learn future attacks, but also serves as a defense countermeasure. The simulated scenarios of this dissertation show that Cognitive Security Framework isbest suited for both homogeneous and heterogeneous sensor networks

Development of a Random Time-Frequency Access Protocol for M2M Communication

This thesis focuses on the design and development of the random time-frequency access protocol in Machine-to-Machine (M2M) communication systems and covers different aspects of the data collision problem in these systems. The randomisation algorithm, used to access channels in the frequency domain, represents the key factor that affects data collisions. This thesis presents a new randomisation algorithm for the channel selection process for M2M technologies. The new algorithm is based on a uniform randomisation distribution and is called the Uniform Randomisation Channel Selection Technique (URCST). This new channel selection algorithm improves system performance and provides a low probability of collision with minimum complexity, power consumption, and hardware resources. Also, URCST is a general randomisation technique which can be utilised by different M2M technologies. The analysis presented in this research confirms that using URCST improves system performance for different M2M technologies, such as Weightless-N and Sigfox, with a massive number of devices. The thesis also provides a rigorous and flexible mathematical model for the random time-frequency access protocol which can precisely describe the performance of different M2M technologies. This model covers various scenarios with multiple groups of devices that employ different transmission characteristics like the number of connected devices, the number of message copies, the number of channels, the payload size, and transmission time. In addition, new and robust simulation testbeds have been built and developed in this research to evaluate the performance of different M2M technologies that utilise the random time-frequency access protocol. These testbeds cover the channel histogram, the probability of collisions, and the mathematical model. The testbeds were designed to support the multiple message copies approach with various groups of devices that are connected to the same base station and employ different transmission characteristics. Utilising the newly developed channel selection algorithm, mathematical model, and testbeds, the research offers a detailed and thorough analysis of the performance of Weightless-N and Sigfox in terms of the message lost ratio (MLR) and power consumption. The analysis shows some useful insights into the performance of M2M systems. For instance, while using multiple message copies improves the system performance, it might degrade the reliability of the system as the number of devices increases beyond a specific limit. Therefore, increasing the number of message copies can be disadvantageous to M2M communication performance