Dissertations / Theses on the topic 'Body area networks (BAN)'

"Body area networks (BAN) is a technology gaining widespread attention for application in medical examination, monitoring and emergency therapy. The basic concept of BAN is monitoring a set of sensors on or inside the human body which enable transfer of vital parameters between the patient´s location and the physician in charge. As body area network has certain characteristics, which impose new demands on performance evaluation of systems for wireless access and localization for medical sensors. However, real-time performance evaluation and localization in wireless body area networks is extremely challenging due to the unfeasibility of experimenting with actual devices inside the human body. Thus, we see a need for a real-time hardware platform, and this thesis addressed this need. In this thesis, we introduced a unique hardware platform for performance evaluation of body area wireless access and in-body localization. This hardware platform utilizes a wideband multipath channel simulator, the Elektrobit PROPSimâ„¢ C8, and a typical medical implantable device, the Zarlink ZL70101 Advanced Development Kit. For simulation of BAN channels, we adopt the channel model defined for the Medical Implant Communication Service (MICS) band. Packet Reception Rate (PRR) is analyzed as the criteria to evaluate the performance of wireless access. Several body area propagation scenarios simulated using this hardware platform are validated, compared and analyzed. We show that among three modulations, two forms of 2FSK and 4FSK. The one with lowest raw data rate achieves best PRR, in other word, best wireless access performance. We also show that the channel model inside the human body predicts better wireless access performance than through the human body. For in-body localization, we focus on a Received Signal Strength (RSS) based localization algorithm. An improved maximum likelihood algorithm is introduced and applied. A number of points along the propagation path in the small intestine are studied and compared. Localization error is analyzed for different sensor positions. We also compared our error result with the Cramèr- Rao lower bound (CRLB), shows that our localization algorithm has acceptable performance. We evaluate multiple medical sensors as device under test with our hardware platform, yielding satisfactory localization performance."

Dans cette thèse, on vise deux types d'applications de l’antenne à résonateur diélectrique (DRA): 1) La réalisation d’un élément rayonnant pour un réseau phasé embarqué sur un véhicule terrestre ou un avion. Cet élément de base requiert une couverture en élévation supérieure à celle des éléments imprimés pour permettre une poursuite typique comprise entre ±70°. La couverture dans un cône large est assurée avec une bonne pureté de polarisation circulaire en alimentant l’antenne à travers deux ouvertures à fente en H orthogonales parfaitement découplées en bande X. 2) La deuxième structure est destinée à la diversité d’antennes dans le contexte des réseaux corporels embarqués ou Body Area Network (BAN). L’antenne à diversité combine une antenne fente en boucle avec un DRA ce qui permet dans un espace compact de réaliser des diagrammes de type “broadside” et “endfire” respectivement. Les alimentations considérées sont de 2 types; Soit purement planaire (microruban et coplanaire) soit mixte en combinant une alimentation coaxiale et une alimentation coplanaire. Caractéristiques principales des antennes à résonateur diélectrique (DRA): Pour répondre aux attentes des utilisateurs en termes de débit, les systèmes de communication sans fils se tournent vers des fréquences de plus en plus élevées. La conséquence de cette montée en fréquence est notamment l’augmentation des pertes au niveau des éléments conducteurs et donc une diminution de l’efficacité globale des systèmes de communication. Dans ces circonstances, les DRA offre de meilleurs résultats par rapport à d'autres familles d'antennes à base d’éléments métalliques. De plus, les DRA offrent des pertes diélectriques négligeables, elles sont peu sensibles aux variations de température et s’intègrent facilement sur des technologies de fabrication planaires<br>Technologies such as direct broad cast satellite system (DBSS), Geosynchronous Earth Orbit (GEO) and Low Earth Orbit (LEO) satellite communications , global positioning system (GPS), high accuracy airborne navigation system and a large variety of radar systems demand for high level of antenna performance. Similar is the requirement for upcoming land based wireless systems such as cellular and indoor communication systems that is needed some more specific and additional features added to the antenna to compensate for the deficiencies encountered in system's performance. Though metallic antennas are capable enough to fulfil all the operational requirements, however at very high frequencies and under hostile temperature conditions they are constrained to face certain limitations. To avoid these constraints the performance of Dielectric Resonator Antennas (DRAs) is evaluated and their new applications are proposed. In the thesis, two types of antenna applications are sought :-First is for tracking and satellite applications that needs a larger aperture coverage in elevation plane. This coverage is realized with a good CP purity by proposing two ports dual linearly polarized DRA working at X-band. The DRA is excited by two orthogonal H-shaped aperture slots yielding two orthogonal polarizations in the broadside direction. A common impedance bandwidth of 5.9% and input port isolation of -35 dB are obtained. The broadside radiation patterns are found to be highly symmetric and stable with cross polarization levels -15dB or better over the entire matching frequency band. The maximum measured gain is found to be 2.5dBi at 8.4 GHz.- The 2nd type of antenna is a dual pattern diversity antenna to be used in the Body Area Network (BAN) context. This antenna combines a slot loop and DRA yielding broadside and end-fire radiation patterns respectively. Based upon the feeding techniques, the DG antenna is further divided into two categories one with planar feeds and the other with non-planar feeds (slot loop excited by planar CPW but DRA excited by vertical monopole) .Both types are successfully designed and measured upon body when configured into different propagation scenarios. The non-planar feeds antenna allows wider common impedance bandwidths than the planar feeds (4.95% vs 1.5%).In both cases, a maximum value of DG=9.5dB was achieved when diversity performance tests were carried out in rich fading environments. This value is close to the one (10 dB) theoretically reached in a pure Rayleigh environment and was obtained with efficiencies of 70% and 85% for the slot loop and the DRA respectively. Therefore, we conclude that these antennas could be used on the shoulders or the chest of professional clothes (firemen, policemen, soldier) where full planar integration is not a key issue but where the communication must be efficient in harsh environments and for various gestures, positions and scenarios

The main concept of Body-Coupled Communication (BCC) is to transmit the electrical information through the human body as a communication medium by means of capacitive coupling. Nowadays the current research of wireless body area network are expanding more with the new ideas and topologies for better result in respect to the low power and area, security, reliability and sensitivity since it is first introduced by the Zimmerman in 1995. In contrast with the other existing wireless communication technology such as WiFi, Bluetooth and Zigbee, the BCC is going to increase the number of applications as well as solves the problem with the cell based communication system depending upon the frequency allocation. In addition, this promising technology has been standardized by a task group named IEEE 802.15.6 addressing a reliable and feasible system for low power in-body and on-body nodes that serves a variety of medical and non medical applications. The entire BAN project is divided into three major parts consisting of application layer, digital baseband and analog front end (AFE) transceiver. In the thesis work a strong driver circuit for BCC is implemented as an analog front end transmitter (Tx). The primary purpose of the study is to transmit a strong signal as the signal is attenuated by the body around 60 dB. The Driver circuit is cascaded of two single-stage inverter and an identical inverter with drain resistor. The entire driver circuit is designed with ST65 nm CMOS technology with 1.2 V supply operated at 10 MHz frequency, has a driving capability of 6 mA which is the basic requirement. The performance of the transmitter is compared with the other architecture by integrating different analysis such as corner analysis, noise analysis and eye diagram. The cycle to cycle jitter is 0.87% which is well below to the maximum point and the power supply rejection ratio (PSRR) is 65 dB indicates the good emission of supply noise. In addition, the transmitter does not require a filter to emit the noise because the body acts like a low pass filter. In conclusion the findings of the thesis work is quite healthy compared to the previous work. Finally, there is some point to improve for the driver circuit in respect to the power consumption, propagation delay and leakage power in the future.

Technologies such as direct broad cast satellite system (DBSS), Geosynchronous Earth Orbit (GEO) and Low Earth Orbit (LEO) satellite communications , global positioning system (GPS), high accuracy airborne navigation system and a large variety of radar systems demand for high level of antenna performance. Similar is the requirement for upcoming land based wireless systems such as cellular and indoor communication systems that is needed some more specific and additional features added to the antenna to compensate for the deficiencies encountered in system's performance. Though metallic antennas are capable enough to fulfil all the operational requirements, however at very high frequencies and under hostile temperature conditions they are constrained to face certain limitations. To avoid these constraints the performance of Dielectric Resonator Antennas (DRAs) is evaluated and their new applications are proposed. In the thesis, two types of antenna applications are sought :-First is for tracking and satellite applications that needs a larger aperture coverage in elevation plane. This coverage is realized with a good CP purity by proposing two ports dual linearly polarized DRA working at X-band. The DRA is excited by two orthogonal H-shaped aperture slots yielding two orthogonal polarizations in the broadside direction. A common impedance bandwidth of 5.9% and input port isolation of -35 dB are obtained. The broadside radiation patterns are found to be highly symmetric and stable with cross polarization levels -15dB or better over the entire matching frequency band. The maximum measured gain is found to be 2.5dBi at 8.4 GHz.- The 2nd type of antenna is a dual pattern diversity antenna to be used in the Body Area Network (BAN) context. This antenna combines a slot loop and DRA yielding broadside and end-fire radiation patterns respectively. Based upon the feeding techniques, the DG antenna is further divided into two categories one with planar feeds and the other with non-planar feeds (slot loop excited by planar CPW but DRA excited by vertical monopole) .Both types are successfully designed and measured upon body when configured into different propagation scenarios. The non-planar feeds antenna allows wider common impedance bandwidths than the planar feeds (4.95% vs 1.5%).In both cases, a maximum value of DG=9.5dB was achieved when diversity performance tests were carried out in rich fading environments. This value is close to the one (10 dB) theoretically reached in a pure Rayleigh environment and was obtained with efficiencies of 70% and 85% for the slot loop and the DRA respectively. Therefore, we conclude that these antennas could be used on the shoulders or the chest of professional clothes (firemen, policemen, soldier) where full planar integration is not a key issue but where the communication must be efficient in harsh environments and for various gestures, positions and scenarios

Cooperative wireless communication is an attractive technique to explore the spatial channel resources by coordination across multiple links, which can greatly improve the communication performance over single links. In this dissertation, we study the cooperative multi-link channel properties by geometric approaches in body area networks (BANs) and cellular networks respectively.<p><p>In the part of BANs, the dynamic narrowband on-body channels under body motions are modeled statistically on their temporal and spatial fading based on anechoic and indoor measurements. Common body scattering is observed to form inter-link correlation between links closely distributed and between links having synchronized movements of communication nodes. An analytical model is developed to explain the physical mechanisms of the dynamic body scattering. The on-body channel impacts to simple cooperation protocols are evaluated based on realistic measurements. <p><p>In the part of cellular networks, the cluster-level multi-link COST 2100 MIMO channel model is developed with concrete modeling concepts, complete parameterization and implementation methods, and a compatible structure for both single-link and multi-link scenarios. The cluster link-commonness is introduced to the model to describe the multi-link properties. The multi-link impacts by the model are also evaluated in a distributed MIMO system by comparing its sum-rate capacity at different ratios of cluster link-commonness.<br>Doctorat en Sciences de l'ingénieur<br>info:eu-repo/semantics/nonPublished

Gait analysis is the systematic study of human walking. Clinical gait analysis is the process by which quantitative information is collected for the assessment and decision-making of any gait disorder. Although observational gait analysis is the therapistâ s primary clinical tool for describing the quality of a patientâ s walking pattern, it can be very unreliable. Modern gait analysis is facilitated through the use of specialized equipment. Currently, accurate gait analysis requires dedicated laboratories with complex settings and highly skilled operators. Wearable locomotion tracking systems are available, but they are not sufficiently accurate for clinical gait analysis. At the same time, wireless healthcare is evolving. Particularly, ultra wideband (UWB) is a promising technology that has the potential for accurate ranging and positioning in dense multi-path environments. Moreover, impulse-radio UWB (IR-UWB) is suitable for low-power and low-cost implementation, which makes it an attractive candidate for wearable, low-cost, and battery-powered health monitoring systems. The goal of this research is to propose and investigate a full-body wireless wearable human locomotion tracking system using UWB radios. Ultimately, the proposed system should be capable of distinguishing between normal and abnormal gait, making it suitable for accurate clinical gait analysis.<br>Ph. D.

Les réseaux BAN (Body Area Network) révolutionnent le concept de la surveillance et de la prise en charge à distance de la santé du patient. Le BAN fournit des informations sur l'état de santé du patient en temps réel quelque soit l'endroit où il se trouve. Dans le « télé monitoring », des capteurs de mouvement, de respiration ou du rythme cardiaque placés à l'intérieur ou sur le corps humain transmettent des données via le réseau sans fil constituant le BAN, une antenne étant associée à chaque nœud du réseau. La communication peut être in/on, on/on ou on/off selon que les antennes sont placées à l'intérieur, sur ou à l'extérieur du corps. Le développement des BAN nécessite la réalisation de modèles (ou fantômes) simulant au mieux les propriétés électromagnétiques du corps humain. Des antennes portables, miniaturisées doivent être réalisées avec des contraintes d'intégration d'une part (aux vêtements, à des objets type montre ou badge), des contraintes de résistance ou de prise en compte de l'influence du corps d'autre part. La réduction de l'impact des antennes sur les tissus en terme de SAR (Specific Absorption Rate) doit également être considérée. Dans ce travail, l'objectif est de développer des fantômes valables pour les communications dans et sur le corps. Les matériaux de base sélectionnés sont d'origine biologique (biocéramiques et biopolymères) avec des propriétés proches de celles des tissus humains. Ces fantômes étant biocompatibles, ils sont essentiellement non toxiques alors que les fantômes usuels le sont en général. D'autre part, différents types d'antennes conformables, fonctionnant dans la bande ISM 2.4 GHz ont été développées et étudiées dans la perspective du BAN. Les antennes voient leur adaptation et leur efficacité chuter au contact ou à proximité du corps, ce qui constitue un écueil majeur pour établir une bonne communication. Différentes méthodes permettant de réduire l'influence du corps (plan de masse à l'arrière, surface haute impédance, feuille de ferrite polymère) sont testés et leurs avantages et inconvénients développés. Des mesures de SAR permettent aussi de démontrer l'efficacité de ces méthodes sur la réduction de la puissance absorbée par les tissus. Au final, ce travail apporte une contribution à l'étude théorique et expérimentale de l'interaction entre corps humain et antenne dans le cadre des réseaux BAN appliqués à la télésurveillance de la santé

[ES] La población mundial en países desarrollados está envejeciendo y con ello existe un aumento de enfermedades en gran medida causadas por la edad. Las nuevas tecnologías médicas pueden ayudar a detectar, diagnosticar y tratar estas enfermedades y con ello ahorrar dinero, tiempo y recursos de los sistemas sanitarios. Las tecnologías inalámbricas implantables han abierto un nuevo panorama para la próxima generación de tecnologías médicas. Frecuencias como la Ultra Wide-Band (UWB) de 3.1 a 10.6 GHz están siendo consideradas para la nueva generación de dispositivos inalámbricos para dentro del cuerpo humano. Las características como el reducido tamaño de las antenas, la baja potencia de transmisión y la alta velocidad de datos son las más buscadas en este tipo de dispositivos. El problema surge porque el cuerpo humano depende de la frecuencia de modo que a mayores frecuencias, mayores son las pérdidas por propagación. Conociendo el canal de transmisión se puede solventar el problema de las altas pérdidas. Esta tesis tiene como objetivo caracterizar el canal de radio frecuencia (RF) para la nueva generación de dispositivos médicos implantables. Para caracterizar el canal se han empleado tres diferentes metodologías: simulaciones numéricas, medidas en phantom y experimentos en animales vivos. Las medidas en phantom fueron realizadas en un nuevo sistema de medidas expresamente disen¿ados para medidas de dentro a fuera del cuerpo humano en la banda de frecuencias UWB. Además, se utilizó un novedoso recipiente con dos capas de phantom imitando la zona gastrointestinal del cuerpo. Estos phantoms fueron creados para este tipo de medidas y son extremadamente precisos a las frecuencias UWB. Para los experimentos en animales se utilizaron cerdos y se intentó reproducir en ellos las medidas previamente realizadas en phantom. Las simulaciones software se realizaron con la intención de replicar ambas metodologías. Una vez realizados los experimentos se realizó un extensivo estudio del canal en dominio frecuencial y temporal. Mas en detalle, se compararon las antenas usadas en la recepción y transmisión, el efecto de la grasa en el canal, la formas del recipiente contenedor de phantom y las componentesmulticamino. Como resultado se ha propuesto un modelo de propagación del canal para la banda baja de las frecuencias UWB (3.1 -5.1 GHz) para la zona gastrointestinal del cuerpo humano. Este modelo de propagación ha sido validado utilizando las tres metodologías previamente descritas y comparada con otros estudios existentes en literatura. Finalmente, se midió el canal de propagación para una determinada aplicación a bajas frecuencias con señales UWB. También se realizaron medidas del canal de propagación en la zona cardíaca del cuerpo humano desde un punto de vista de seguridad de datos. Los resultados obtenidos en esta tesis confirman los beneficios que tendría la utilización de frecuencias UWB para las futuras generaciones de dispositivos médicos implantables.<br>[CA] La població mundial a països desenvolupats està envellint-se i enfrontant-se a un augment d'infermetats principalment causades per la edat. Les noves tecnologies mèdiques poden ajudar a detectar, diagnosticar i tractar aquestes malalties, estalviant diners, temps i recursos sanitaris. Els dispositius implantables sense fils han generat un nou panorama per a les noves generacions de dispositius mèdics. Les freqüències com la banda de UWB estan sent considerades per a les futures tecnologies implantables. La reduïda grandària de les antenes, la baixa potència de transmissió i les altes velocitats de dades son característiques buscades per als dispositius implantables. Per contra, els éssers humans depenen de la freqüència en el sentit que a majors freqüències, majors les pèrdues per propagació quan el senyal travessa el cos humà d'interior a exterior. Per solventar aquestes pèrdues el canal de propagació s'ha d'entendre i conèixer de la millor manera possible. Aquesta tesi doctoral te com a objectiu caracteritzar el canal de radio freqüència (RF) per a la nova generació de dispositius mèdics implantables. S'han emprat tres metodologies diferents per a realitzar aquesta caracterització: simulacions software, mesures amb fantomes i experiments amb animals vius. Els experiments amb fantomes es van realitzar a un sistema de mesures dissenyat expressament per a les transmissions de dins a fora del cos humà a les freqüències UWB. També es van utilitzar un contenidor per als fantomes de dues capes, imitant l'area gastrointestinal dels humans. Per als experiments a animals es van emprar porcs, replicant els experiments al laboratori en fantomes de la forma més semblant possible. Les simulacions software foren dissenyades per a imitar les experiments amb fantomes i animals. Després dels experiments el canal de propagació es va investigar exhaustivament des del domini freqüèncial i temporal. S'ha observat com les antenes en transmissió i recepció afecten al senyal, la influència de la grassa, la forma del contenidor de fantoma i les possibles contribucions multicamí. Finalment es proposa un nou model de propagació per a les baixes freqüències UWB (3.1 a 5.1 GHz) per a la zona GI del cos humà. El model es va validar utilitzant les tres metodologies abans esmentades i també foren comparades amb model ja existents a la literature. Finalment des d'un punt de vista aplicat, el canal es va avaluar per al senyal UWB a baixes freqüències (60 MHz). A més a més, per a la nova generació de marcapassos sense fil es va investigar el canal des d'un punt de vista de seguretat de dades. Els resultats obtinguts a aquesta tesi confirmen els avantatges d'emprar la banda de freqüències UWB per a la nova generació de dispositius médics implantables.<br>[EN] The current global population in developed countries is becoming older and facing an increase in diseases mainly caused by age. New medical technologies can help to detect, diagnose and treat illness, saving money, time, and resources of physicians. Wireless in-body devices opened a new scenario for the next generation of medical devices. Frequencies like the Ultra Wide-band (UWB) frequency band (3.1 - 10.6 GHz) are being considered for the next generation of in-body wireless devices. The small size of the antennas, the low power transmission, and the higher data rate are desirable characteristics for in-body devices. However, the human body is frequency ependent, which means higher losses of the radio frequency (RF) signal from in- to out-side the body as the frequency increases. To overcome this, the propagation channel has to be understood and known as much possible to process the signal accordingly. This dissertation aims to characterize the (RF) channel for the future of in-body medical devices. Three different methodologies have been used to characterize the channel: numerical simulations, phantom measurements, and living animals experiments. The phantom measurements were performed in a novel testbed designed for the purpose of in-body measurements at the UWB frequency band. Moreover, multi-layer high accurate phantoms mimicking the gastrointesintal (GI) area were employed. The animal experiments were conducted in living pigs, replicating in the fairest way as possible the phantom measurement campaigns. Lastly, the software simulations were designed to replicate the experimental measurements. An in-depth and detail analysis of the channel was performed in both, frequency and time domain. Concretely, the performance of the receiving and transmitting antennas, the effect of the fat, the shape of the phantom container, and the multipath components were evaluated. Finally, a novel path loss model was obtained for the low UWB frequency band (3.1 - 5.1 GHz) at GI scenarios. The model was validated using the three methodologies and compared with previous models in literature. Finally, from a practical case point of view, the channel was also evaluated for UWB signals at lower frequencies (60 MHz) for the GI area. In addition, for the next generation of leadless pacemakers the security link between the heart and an external device was also evaluated. The results obtained in this dissertation reaffirm the benefits of using the UWB frequency band for the next generation of wireless in-body medical devices.<br>Pérez Simbor, S. (2019). In-body to On-body Experimental UWB Channel Characterization for the Human Gastrointestinal Area [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/133034<br>TESIS

Having a device with the capability of measure motions from gait produced by a human being, could be of most importance in medicine and sports. Physicians or researchers could measure and analyse key features of a person's gait for the purpose of rehabilitation or science, regarding neurological disabilities. Also in sports, professionals and hobbyists could use such a device for improving their technique or prevent injuries when performing. In this master thesis, I present the research of what technology is capable of today, regarding gait analysis devices. The research that was done has then help the development of a suggested standalone hardware sensor node for a Body Area Network, that can support research in gait analysis. Furthermore, several algorithms like for instance UWB Real-Time Location and Dead Reckoning IMU/AHRS algorithms, have been implemented and tested for the purpose of measuring motions and be able to run on the sensor node device. The work in this thesis shows that a IMU sensor have great potentials for generating high rate motion data while performing on a small mobile device. The UWB technology on the other hand, indicates a disappointment in performance regarding the intended application but can still be useful for wireless communication between sensor nodes. The report also points out the importance of using a high performance micro controller for achieving high accuracy in measurements.

Long-term evolution (LTE) standard has been successfully stabilized, and launched in several areas. However, the required channel capacity is expected to increase significantly as the explosively increasing number of smart-phone users implies. Hence, this is already the time for leading researchers to concentrate on a new multiple access scheme in wireless communications to satisfy the channel capacity that those smart users will want in the not-too-distant future. The diversity and multiplexing in a new domain - polarization domain - can be a strong candidate for the solution to that problem in future wireless communication systems. This research contributes largely to the comprehensive understanding of polarized wireless channels and a new multiple access scheme in the polarization domain - polarization division multiple access (PDMA). The thesis consists of three streams: 1) a novel geometrical theory and models for fixed-to-mobile (F2M) and mobile-to-mobile (M2M) polarized wireless channels; 2) a new wireless body area network (BAN) polarized channel modeling; and 3) a novel PDMA scheme. The proposed geometrical theory and models reveal the origin and mechanism of channel depolarization with excellent agreement with empirical data in terms of cross-polarization discrimination (XPD), which is the principal measure of channel depolarization. Further, a novel PDMA scheme utilizing polarization-filtering detection and collaborative transmitter-receiver-polarization (Tx-Rx-polarization) adjustment, is designed considering cellular orthogonal frequency division multiplexing (OFDM) systems. The novel PDMA scheme has large potential to be utilized with the conventional time, frequency, and code division multiple access (TDMA, FDMA, and CDMA); and spatial multiplexing for next-generation wireless communication systems.

Les réseaux à l'origine métropolitains, ont connu une tendance à rétrécir pour aujourd'hui se concentrer autour de l'être humain. Avec des équipements de plus en plus miniatures et les utilisateurs désireux de disposer en permanence des services qui leur sont accessibles à domicile, le réseau est envisagé plus petit, plus proche du corps. On assiste alors à l'émergence du réseau corporel, le Body Area Network (BAN), qui est constitué d'éléments situés sur le corps, à l'intérieur ou encore à une courte distance. Ce réseau à portée du corps génère de nouvelles problématiques, notamment celles de la puissance rayonnée par les équipements, leur taille, leur poids...Les applications et usages envisagés pour un tel réseau sont variés et couvrent plusieurs domaines d'activités, en l'occurrence le secteur du médical, du sport, et le multimédia. Ce réseau doit donc reposer sur une couche physique qui s'adapte aux contraintes de ces diverses applications, tout en favorisant des équipements de faible taille, faible complexité et de forte autonomie. La technologie Ultra Large Bande impulsionnelle (UWB-IR) est porteuse de nombreuses promesses pour satisfaire en partie les besoins des réseaux BAN, car autorisant des débits aussi bien réduits qu'élevés, et les architectures d'émission et réception utilisables pour cette technologie rendent possibles des équipements à faible complexité et faible coût, et dont la consommation énergétique est réduite.Ce travail de thèse a débuté alors qu'un processus de normalisation sur les BAN était en cours. L'objectif des travaux menés était de pouvoir contribuer en partie à ce processus de normalisation par la proposition d'une couche physique basée sur la radio impulsionnelle UWB (UWB-IR). Ainsi notre étude a porté sur le paramétrage de cette couche physique à partir de l'analyse des contraintes et requis techniques d'un réseau BAN. Les performances de cette couche physique ont ensuite été évaluées dans un contexte de canal UWB BAN et suivant le type d'architecture en réception, en particulier pour le récepteur non-cohérent. Enfin, une attention a été apportée sur la robustesse de la liaison en présence d'interférences bande étroite. Dans l'ensemble, ce travail a permis d'étudier et d'évaluer la pertinence d'une couche physique UWB-IR dans le contexte du réseau BAN

Patient’s mobility throughout his lifetime leaves a trial of information scattered in laboratories, clinical institutes, primary care units, and other hospitals. Hence, the medical history of a patient is valuable when subjected to special healthcare units or undergoes home-care/personal-care in elderly stage cases. Despite the rhetoric about patient-centred care, few attempts were made to measure and improve in this arena. In this thesis, we will describe and implement a high-level view of a Patient Centric information management, deploying at a preliminary stage, the use of Agent Technologies and Grid Computing. Thus, developing and proposing an infrastructure that allows us to monitor and survey the patient, from the doctor’s point of view, and investigate a Persona, from the patients’ side, that functions and collaborates among different medical information structures. The Persona will attempt to interconnect all the major agents (human and software), and realize a distributed grid info-structure that directly affect the patient, therefore, revealing an adequate and cost-effective solution for most critical information needs. The results comprehended in the literature survey, consolidating Healthcare Information Management with emerged intelligent Multi-Agent System Technologies (MAS) and Grid Computing; intends to provide a solid basis for further advancements and assessments in this field, by bridging and proposing a framework between the home-care sector and the flexible agent architecture throughout the healthcare domain.

Récemment la bande 60 GHz a été mise en avant pour le développement des réseaux de communication sans fil centrés sur le corps humain. Cet intérêt de la bande 60 GHz pour les applications BAN (Body Area Network) s'explique par les avantages clefs qu'elle procure par rapport aux bandes de fréquence plus basses (possibilité de débits de données supérieurs à 7 Gbit/s, réduction des interférences avec les réseaux voisin, compacité des dispositifs, etc). Le nombre d'application de communication BAN est amené à croître dans les années à venir avec le déploiement de la 5ème génération de réseaux de télécommunications mobiles. Afin de protéger efficacement les utilisateurs des expositions générées par ces applications BAN à 60 GHz, il est nécessaire de se pencher sur les problématiques de réduction du couplage corps/antennes, mais également sur l'évaluation et la quantification du niveau d'exposition du corps à 60 GHz. Pour cela, les travaux de thèse ont été organisés suivant trois axes de recherche : le premier consiste à mettre en évidence et à quantifier l'impact de certains choix de conception en matière d'antennes sur le couplage avec le corps humain ; le second porte sur les outils et les méthodes utilisés pour estimer l'impact thermique d'une exposition électromagnétique 60 GHz sur le fantôme équivalent de la peau ; et le troisième propose une nouvelle approche à la fois dosimétrique et thermique pour évaluer et analyser le couplage corps/antennes en bande millimétrique<br>The 60-GHz frequency band has been identified recently as attractive for body centric wireless communication development. Indeed, this band has several key advantages compared to lower frequency bands as high data rates above 7 Gbit/s, low risks of interference with neighboring wireless networks and compact devices. With the development of the future 5th generation of mobile networks in the millimeter-wave band, the number of BAN applications at 60 GHz should increase. To avoid health effects and protect user against an electromagnetic exposure of BAN devices at 60 GHz, the reduction of the coupling between human body and antennas, as well as the evaluation and quantification of exposure are main research aspect of the thesis. The main thesis contributions are divided in three parts: a quantification of antenna design effects on the interactions between human body and antennas; a study of tools and methods used to assess thermal effects due to 60 GHz exposure on a skin-equivalent phantom; and a new dosimetric and thermal approach to evaluate interaction between human body and BAN antennas at 60 GHz

Les études présentées dans cette thèse font l'objet d'un travail innovant concernant la conception des antennes pour les réseaux de type BAN et la modélisation des canaux associés. L'ouvrage de thèse est réparti en quatre chapitres. Deux chapitres sont consacrés à la modélisation de la propagation le long du corps où l'on montre que les formulations analytiques d'ondes de surface et d'ondes rampantes sont applicables dans ce contexte. L'effet des tissus adipeux est également pris en compte par le biais d'un modèle à trois couches (peau, graisse et muscle) et renseigne sur la variabilité du bilan de liaison suivant les personnes. Ce type de modélisation est le premier à inclure les formes du corps, les caractéristiques électriques des tissus biologiques et les caractéristiques de rayonnement des antennes. Une méthode basée sur l'autocorrélation du canal est également présentée afin de connaître les temps de cohérences des évanouissements lents et rapides. Par la suite, il est montré comment les évanouissements lents sont extraits par le biais d'un filtrage FFT fonction du temps de cohérence associé. L'étude des canaux se termine sur une série de mesures en chambre anéchoïde qui a permis de vérifier la validité des modèles analytiques. Des mesures en milieu indoor ont abouti à la proposition de plusieurs modèles statistiques basés sur une loi de Nakagami-m fonction de la distance sur le corps. Deux autres chapitres sont consacrés à la conception d'antennes à proximité de tissus biologiques et devant être intégrées dans des biocapteurs ou des vêtements. Pour cela, nous nous sommes particulièrement intéressés aux structures en F-inversé comme les IFA imprimées et les PIFA. Nous avons également réalisé des monopôles courts ayant un comportement de type magnétique. Nous montrons par le biais de simulations et de mesures sur un fantôme que seules les antennes du type monopôle et PIFA permettent une bonne excitation des ondes de surface. On montre par la suite l'influence du facteur de qualité d'une antenne sur son rendement et l'on en conclue qu'une antenne doit présenter un facteur de qualité faible pour avoir un bon rendement. La désensibilisation d'une antenne face au corps est également présentée. L'emploi de feuilles de ferrites aide à concentrer le champ réactif et limite ainsi les inévitables désadaptations dues au corps. Le coefficient de qualité joue également un rôle important dans le comportement de l'antenne face aux variabilités des tissus biologiques. L'estimation du rendement est un autre point difficile à réaliser lorsque les antennes sont sur le corps. Malgré tout nous proposons une nouvelle méthode que nous vérifions par simulation. Finalement, une structure à diversité est également proposée. Cette dernière tient compte des connaissances acquises au long de ce travail de recherche. Une sélection des meilleurs types d'antennes du point de vu canal et rendement est réalisée. La structure choisie est composée d'une PIFA et d'un monopôle court découplés par le biais de fentes λ/4. Des mesures in situ en milieu indoor donnent un gain en diversité maximum de 8.1 dB pour un schéma de type sélection

Body Area Networks (BAN) are unique in that the large-scale mobility of users alongside the complexity of body movements allows the network itself to travel across a diverse range of operating domains or even to enter new and unknown environments. These body movements along with the diversity of these unknown environments can create unique transmission channels. This network mobility is unlike node mobility in that sensed changes in inter-network interference level may be used to identify opportunities for intelligent inter-networking, for example, by merging or splitting from other networks, thus providing an extra degree of freedom. As the BAN network travels it will cause and be subject to inter-network interference but it also has the opportunity to sense and interact with a range of other networks. Using a series of carefully controlled measurements of the mesh interconnectivity both within and between ambulatory BANs as well as a stationary desk-based network, this thesis presents an investigation of context aware body area network (CABAN) interference detection at the physical layer. This thesis, also gives consideration to the co-existence of multiple co-located BAN users and the complex interaction of body-shadowing, user movement as well as the multi:"path environment itself and its impact on channel conditions. The final aspect of the thesis investigates the interaction between physical layer characteristics and packet error rate (PER) at the data link layer as two independent BANs operating in CSMA networks as they could merge and split

Mestrado em Engenharia Electrónica e de Telecomunicações<br>Actualmente existem diversos meios de pagamentos electrónicos, os quais têm vindo a ser cada vez mais utilizados a nível mundial. Com a evolução da tecnologia e dos dispositivos móveis no decorrer da última década, surgiram novas tendências para os sistemas de pagamento, nomeadamente a realização de pagamentos móveis através de telemóveis ou smartphones. O sistema de pagamento via NFC, o qual tem vindo a afirmar-se cada vez mais neste paradigma, é um sistema que permite realizar pagamentos móveis por proximidade e de forma segura utilizando um smartphone equipado com a devida tecnologia. Contudo, é necessário que o utilizador aproxime o seu dispositivo do terminal de pagamentos durante todo o processo de pagamento, algo que poderá ser incómodo ou mesmo inconveniente em determinadas situações. O sistema de pagamento via BCC, desenvolvido neste projecto de dissertação de mestrado, procura oferecer uma nova solução no âmbito dos sistemas de pagamento móveis. O mesmo utiliza o corpo humano como meio de comunicação, fazendo uso de tecnologia que permite a transmissão e a recepção da informação por acoplamento capacitivo ao corpo humano. Devido ao confinamento da comunicação no corpo humano, com este sistema aumenta-se a segurança de um pagamento e eliminam-se os incómodos e inconveniências do sistema de pagamento via NFC.<br>There are currently various means of electronic payments, which have been increasingly used worldwide. With the evolution of technology and mobile devices over the last decade, new trends in payment systems have emerged, namely the realization of mobile payments using mobile phones or smartphones. The NFC payment system, which has been increasingly asserting itself in this paradigm, is a system that allows performing mobile payments by proximity and securely using an equipped smartphone with the proper technology. However, it is necessary that the user approaches the mobile device to the POS terminal throughout the whole payment process, something that can be uncomfortable or inconvenient in certain situations. The BCC payment system, developed in this Master’s dissertation project, seeks to offer a new solution in the framework of mobile payment systems. It uses the human body as a communication medium, making use of technology that allows the transmission and reception of information through capa-itive coupling to the human body. Due to the communication confinement in the human body, this system increases the security of a payment and eliminates the hassle and inconveniences of the NFC payment system.

Healthcare is changing, correction ... healthcare is in need of change. The population ageing, the increase in chronic and heart diseases and just the increase in population size will overwhelm the current hospital-centric healthcare. There is a growing interest by individuals to monitor their own physiology. Not only for sport activities, but also to control their own diseases. They are changing from the passive healthcare receiver to a proactive self-healthcare taker. The focus is shifting from hospital centred treatment to a patient-centric healthcare monitoring. Continuous, everyday, wearable monitoring and actuating is part of this change. In this setting, sensors that monitor the heart, blood pressure, movement, brain activity, dopamine levels, and actuators that pump insulin, 'pump' the heart, deliver drugs to specific organs, stimulate the brain are needed as pervasive components in and on the body. They will tend for people's need of self-monitoring and facilitate healthcare delivery. These components around a human body that communicate to sense and act in a coordinated fashion make a Body Area Network (BAN). In most cases, and in our view, a central, more powerful component will act as the coordinator of this network. These networks aim to augment the power to monitor the human body and react to problems discovered with this observation. One key advantage of this system is their overarching view of the whole network. That is, the central component can have an understanding of all the monitored signals and correlate them to better evaluate and react to problems. This is the focus of our thesis. In this document we argue that this multi-parameter correlation of the heterogeneous sensed information is not being handled in BANs. The current view depends exclusively on the applica- tion that is using the network and its understanding of the parameters. This means that every application will oversee the BAN's heterogeneous resources managing them directly without taking into consideration other applications, their needs and knowledge. There are several physiological correlations already known by the medical field. Correlating blood pressure and cross sectional area of blood vessels to calculate blood velocity, estimating oxygen delivery from cardiac output and oxygen saturation, are such examples. This knowledge should be available in a BAN and shared by the several applications that make use of the network. This architecture implies a central component that manages the knowledge and the resources. And this is, in our view, missing in BANs. Our proposal is a middleware layer that abstracts the underlying BAN's resources to the applica- tion, providing instead an information model to be queried. The model describes the correlations for producing new information that the middleware knows about. Naturally, the raw sensed data is also part of the model. The middleware hides the specificities of the nodes that constitute the BAN, by making available their sensed production. Applications are able to query for information attaching requirements to these requests. The middleware is then responsible for satisfying the requests while optimising the resource usage of the BAN.Our architecture proposal is divided in two corresponding layers, one that abstracts the nodes' hardware (hiding node's particularities) and the information layer that describes information available and how it is correlated. A prototype implementation of the architecture was done to illustrate the concept.

With the advancements in technology and computing environment capabilities, the number of devices that people carry has increased exponentially. This increase initially occurred as a result of necessity to monitor the human body condition due to chronic diseases, heart problems etc. Later, individuals’ interest was drawn towards self-monitoring their physiology and health care. This is achieved by implanting various sensors that can proactively monitor the human body based on medical necessity and the health condition of the user. Sensors connected on a human body perceive phenomena such as locomotion or heartbeat, and act accordingly to form a Body Area Network. The primary concern of these sensors is to ensure a secure way of communication and coordination among the devices to form a flawless system. A secondary concern is wireless sensor authentication, which ensures trustworthiness and reliable gathering of a user’s data. To address this concern, we designed a secure approach using low cost accelerometers to authenticate sensors in Body Area Networks. To ensure authentication in on-body sensor networks, we need a mechanism which intuitively proves all the communicating nodes are trusted ones. In order to achieve sensor authentication, we used accelerometer data gathered from sensors to distinguish whether or not the devices are carried on waist of same individual’s body. Our approach is focused at analyzing walking patterns recorded from smartphone accelerometers placed in the same location of the user’s body, and we present results showing these sensors record similar pattern.

Nowadays, each user or organization is already connected to a large number of sensor nodes which generate a substantial amount of data, making their management not an obvious issue. In addition, these data can be confidential. For these reasons, developing a secure system managing the data from heterogeneous sensor nodes is a real need. In the first part, we developed a composite-based middleware for wireless sensor networks to communicate with the physical sensors for storing, processing, indexing, analyzing and generating alerts on those sensors data. Each composite is connected to a physical node or used to aggregate data from different composites. Each physical node communicating with the middleware is setup as a composite. The middleware has been used in the context of the European project Mobesens in order to manage data from a sensor network for monitoring water quality. In the second part of the thesis, we proposed a new hybrid authentication and key establishment scheme between senor nodes (SN), gateways (MN) and the middleware (SS). It is based on two protocols. The first protocol intent is the mutual authentication between SS and MN, on providing an asymmetric pair of keys for MN, and on establishing a pairwise key between them. The second protocol aims at authenticating them, and establishing a group key and pairwise keys between SN and the two others. The middleware has been generalized in the third part in order to provide a private space for multi-organization or -user to manage his sensors data using cloud computing. Next, we expanded the composite with gadgets to share securely sensor data in order to provide a secure social sensor network

The smart environments and the connected human seems to be the future of wireless communications. The development of new frequency bands in the millimeter range will allow us to create high data rate communications which will led to the Wireless Body Environment Networks. In this kind of scenarios, it is expected that the user and the environment will interact. In order to develop such new applications, it is necessary to first study the propagation mechanisms and then, the communication channel underlying body centric environments. This thesis treats of channel models for 60 GHz Body Area Networks and more particularly of three kinds of scenarios: (i) the communication between an external base station and a worn node (off-body); (ii) the communication between two worn nodes (on-body); the communication between an external base station and a hand-held device (near-body). An indoor off-body channel model is numerically proposed and implemented. The model is based on the IEEE 802.11ad indoor standard channel at 60 GHz and a fast computation solution of the scattering of a plane wave by a circular cylinder. The model is developed for two orthogonal polarizations and the communications performances are studied. The on-body propagation is studied for two different configurations: line-of-sight and non-line-of-sight communications on the body. These scenarios led to different solutions for the channel knowing as, respectively, Norton’s equations and creeping formulations. These solutions are obtained using simplified geometries which has been experimentally validated. Further, in order to improve the propagation on the human body, a technique using metallic plates has been proposed. This technique has been theoretically studied using Milligton’s equations and experimentally assessed on a flat phantom with the properties of the human skin. The proposed method allows to save up to 20 dB. Finally, the near-body communication scenario has been introduced and studied. The near-body region is extended from 5 to 30 cm away of the user body which corresponds to the arm’s reach and models a handheld device. A numerical algorithm has been proposed to model indoor near-body environments. Also, a special has been given to statistical body shadowing. It has been shown that the fading follows a Two-Wave Diffuse Power distribution.<br>Doctorat en Sciences de l'ingénieur et technologie<br>info:eu-repo/semantics/nonPublished

Dans les réseaux WBAN, les capteurs sont utilisés pour surveiller, collecter et transmettre des signes médicaux et d'autres informations sur le corps humain (EEG, ECG, SpO2, température, etc.) à un nœud principal qu’on appelle « Sink ». Il y a plusieurs préoccupations dans les WBAN, allant de la conception de protocoles de communication fiables et efficaces face à la mobilité du corps humain à une communication faible en consommation énergétique. Les WBAN diffèrent des réseaux de capteurs sans fil typiques à grande échelle et se caractérisent par une mobilité dans le réseau qui suit les mouvements du corps humain et une qualité des liens qui varie en fonction de la posture du porteur. Aussi, la puissance d'émission des capteurs est maintenue faible afin d'améliorer leur autonomie et de réduire l’exposition aux ondes électromagnétiques des porteurs. Par conséquent, compte tenu des effets d’absorption du corps, des réflexions et des interférences, il est difficile de maintenir un lien direct (à un saut) entre le « Sink » et les autres nœuds. La communication multi-sauts représente une alternative viable. Nous avons évalué essentiellement deux primitives de communication: broadcast et converge-cast. Nous avons implémenté différentes stratégies de communication avec le simulateur Omnet++ auquel nous avons intégré le projet Mixim et un modèle de canal réaliste pour un scénario représentatif d'un réseau WBAN. Ce modèle est issu d'une recherche récente de l'informatique biomédicale et décrit les liens entre 7 nœuds, qui appartiennent au même WBAN, et qui sont attachés au corps humain sur la tête, la poitrine, le bras, le poignet, le nombril, la cuisse et la cheville. Les atténuations du signal sur ces liens sont calculées pour 7 postures qui varient entre des positions statiques à fortement mobiles et sont présentées, pour chaque couple de nœuds, sous la forme d’une atténuation moyenne et d’écart-type. Ensuite, nous nous sommes intéressés au problème de broadcast dans WBAN. Nous avons analysé plusieurs stratégies de diffusion inspirées des réseaux DTN avec différents niveaux de connaissance du réseau: des stratégies de type flooding, où les nœuds diffusent les paquets à l'aveugle, et des stratégies basées sur la connaissance du voisinage, où la diffusion est plus contraignante. Nos résultats ont montré que les stratégies de diffusion existantes ne résistent pas face à la mobilité du corps humain et ne peuvent pas être transposées sans des modifications significatives dans un contexte WBAN. Ainsi, nous avons proposé deux nouvelles stratégies de diffusion qui surpassent les stratégies existantes en termes de latence, de couverture du réseau et de la consommation d’énergie des capteurs. Nous avons également analysé la capacité de toutes ces stratégies à assurer l’ordre FIFO (c'est-à-dire les paquets sont reçus dans l'ordre de leur envoi) en les stressant avec différents taux de transmission du nœud « Sink ». Sans exception, les stratégies de diffusion à plat existantes enregistrent une baisse drastique de performance lorsque le taux de transmission augmente. Ainsi, nous avons pu proposer le premier protocole de diffusion inter-couches MAC-réseau, CLBP. Notre protocole exploite la mobilité du corps humain en choisissant soigneusement les liens de communication les plus fiables dans chaque posture. De plus, notre protocole a un mécanisme d'attribution de slots qui réduit la consommation d'énergie, les collisions, l'écoute inactive et la sur-écoute des capteurs. Nous nous sommes également concentrés sur le problème de converge-cast dans les réseaux WBAN. Nous avons adapté à partir des réseaux DTN et WSN des stratégies converge-cast représentatives que nous avons classées en trois catégories: basées sur le modèle du canal, basées sur la diffusion et basées sur multi-chemins. Nous avons étudié trois paramètres: la résilience à la mobilité corporelle, le délai de bout en bout et la consommation d'énergie. [...]<br>The rapid advances in sensors and ultra-low power wireless communication has enabled a new generation of wireless sensor networks: Wireless Body Area Networks (WBAN). WBAN is a recent challenging area. There are several concerns in this area ranging from energy efficient communication to designing delay efficient protocols that support nodes dynamic induced by human body mobility. In WBAN tiny devices are deployed in/on or around a human body, are able to detect and collect the physiological phenomena of the human body (such as: EEG, ECG, SpO2, etc.), and transmit this information to a collector point (i.e Sink) that will process it, take decisions, alert or record. WBAN differs from typical large-scale wireless sensor networks WSN in many aspects: Network size is limited to a dozen of nodes, in-network mobility follows the body movements and the wireless channel has its specificities. Links have a very short range and a quality that varies with the wearer's posture. The transmission power is kept low to improve devices autonomy and reduce wearers electromagnetic exposition. Consequently, the effects of body absorption, reflections and interference cannot be neglected and it is difficult to maintain a direct link (one-hop) between the Sink and all WBAN nodes. Thus, multi-hop communication represents a viable alternative. In this work we investigate energy-efficient multi-hop communication protocols in WBAN. Our work is part of SMART-BAN Self-organizing Mobility Aware, Reliable and Timely Body Area Networks project. In order to evaluate our communication protocols described in the sequel in a specific WBAN scenario, we implemented them under the Omnet++ simulator that we enriched with the Mixim project and a realistic human body mobility and channel model issued from a recent research on biomedical and health informatics. We are interested in WBAN where sensors are placed on the body. We focus on two communication primitives: broadcast and converge-cast. For the broadcasting problem in WBAN, we analyze several broadcast strategies inspired from the area of DTN then we propose two novel broadcast strategies MBP: Mixed Broadcast Protocol and Optimized Flooding: -MBP (Mixed Broadcast Protocol): We proposed this strategy as a mix between the dissemination-based and knowledge-based approaches. -OptFlood (Optimized Flooding): This strategy takes into account the strengths and weaknesses of the basic strategy Flooding. Optimized Flooding is a revised version of Flooding whose purpose is to keep the good end-to-end delay given by Flooding while lowering energy consumption with the simplest way and the minimum cost. Additionally, we performed investigations of independent interest related to the ability of all the studied strategies to ensure the FIFO order consistency property (i.e. packets are received in the order of their sending) when stressed with various transmission rates. These investigations open new and challenging research directions. With no exception, the existing flat broadcast strategies register a dramatic drop of performances when the transmission rate is superior to 11Kb/s. There, we propose the first network-MAC layer broadcast protocol, CLBP, designed for multi-hop communication and resilient to human body postures and mobility. Our protocol is optimized to exploit the human body mobility by carefully choosing the most reliable communication paths in each studied posture. Moreover, our protocol includes a slot assignment mechanism that reduces the energy consumption, collisions, idle listening and overhearing. Additionally, CLBP includes a synchronization scheme that helps nodes to resynchronize with the Sink on the fly. Our protocol outperforms existing flat broadcast strategies in terms of percentage of covered nodes, energy consumption and correct reception of FIFO-ordered packets and maintains its good performances up to 190Kb/s transmission rates. [...]

The medical and economic potential of wireless Body Area Networks (BANs) is gradually being realised especially in the area of medical remote monitoring and telemedicine. Medical BANs will employ both implantable and body worn devices to support a diverse range of applications with throughputs ranging from several bits per hour up to 10 Mbps. The main consideration of this thesis was the long-term power consumption of BAN devices, as these devices have to perform all associated functions such as networking, processing, and RF communications powered usually only by a small battery. Implantable devices are expected to have a lifetime of up to 10 years. The challenge was to accommodate this diverse range of applications within a single wireless network based on a suitably flexible and power efficient medium access control (MAC) protocol. Analyses established that in ultra-low data rate wireless sensor networks (WSN) waking up just to listen to a beacon every superframe can be a major waste of energy. Based on these findings a novel medical medium access control (MedMAC) protocol was developed - capable of providing energy efficient and adaptable channel access in body area networks. The MedMAC protocol achieves significant energy efficiency through a novel synchronisation algorithm which allows the device to sleep through beacons while maintaining synchronisation. Energy efficiency simulations show that the MedMAC protocol outperforms the IEEE 802.15.4 protocol. Results from a comparative analysis of MedMAC and the emerging draft IEEE 802.15.6 wireless standard for BANs show that MedMAC has superior efficiency with energy savings of between 25% and 87% for the presented scenarios. Overall this work demonstrates a new mechanism for achieving significant energy savings for a significant sector of BAN devices that operate at ultra-low data rates.

Le déploiement de biocapteurs sur le corps humain, en vue de la collecte des données physiologiques constitue ce qui est appelé un réseau de capteurs corporel sans fil ou Wireless Body Area Network (WBAN). Ainsi, pour assurer les communications entre les diffèrent composants des WBANs, l’organisme IEEE a établi la norme IEEE 802.15.6, comme norme de communication optimisée pour les terminaux et capteurs exigeants de faible consommation énergétique et fonctionnants dans ou autour du corps humain (mais non limitée aux humains). Dans ce contexte, plusieurs études de simulation ont été menées dans la littérature pour analyser et évaluer les performances du protocole d’accès CSMA/CA de la norme IEEE 802.15.6. De plus, des efforts ont été faits en matière de modélisation de ce protocole afin de mieux analyser les caractéristiques de la norme dans un contexte plus général. Cependant, ces modèles sont partiellement applicables aux applications WBANs qui présentent des trafics réseaux hétérogènes.Cette thèse porte sur la modélisation de la norme IEEE 802.15.6 dans le but de fournir un moyen d’évaluation et d’analyse de cette norme dans divers conditions et situations. Nous avons essayé, à travers les principales contributions réalisées dans le cadre de cette thèse de combler les lacunes des travaux existants comme suit : la première contribution concerne une évaluation des performances de la norme IEEE 802.15.6 utilisant de nombreuses stratégies de gestion des files d’attentes, dans un cadre médical réaliste (surveillance à domicile d'un patient souffrant d’un problème cardiaque). La deuxième contribution propose un modèle de gestion de file d’attente LLQ (Low Latency Queuing) comme complément au protocole CSMA/CA afin de répondre efficacement aux exigences du standard en termes de la Qualité de Service (QoS) pour certains types d’applications.La troisième contribution porte sur la proposition d’un modèle analytique permettant l'étude des performances du protocole d'accès CSMA/CA de la norme IEEE 802.15.6, en termes de latence et du taux de délivrance des paquets, sous l’hypothèse que les WBANs sont composés de nœuds hétérogènes qui génèrent un trafic hétérogène en termes de priorité.La dernière contribution traite la problématique de sécurité dans les réseaux WBANs. Elle propose un protocole de sécurité appelé "Server-Based Secure Key Management for the IEEE 802.15.6 standard" (SBSKM) qui permet au standard de pallier à la vulnérabilité d’usurpation d’identité, par l’inclusion d’un serveur de confiance, responsable de la création, de l'initialisation et de la distribution des clés de chiffrement et de leur renouvellement, ainsi que de garantir l'identité des capteurs qui se joignent au réseau.Mots-clés: réseaux de capteurs corporels (WBANs), IEEE 802.15.6, processus de renouvèlement et de récompense, files d’attente avec priorité, attaques d’usurpation d’identité<br>The deployment of several biosensors on the human body for the collection of physiological data forms what is called a Wireless Body Area Network (WBAN). Thus, to ensure wireless communications between the different components of WBANs, the IEEE has established the IEEE 802.15.6 standard, which is an optimized communication standard for low-power devices that operate on, in, or around the human body (but not limited to humans). In this context, several simulation studies have been conducted in the literature to analyze and evaluate the performance of the IEEE 802.15.6 CSMA/CA access scheme. Also, efforts have been made to model this scheme to better analyze the characteristics of the standard in a more general context. However, these models are partially applicable to WBANs applications with heterogeneous network traffic.This thesis deals mainly with a challenge related to the modeling of the IEEE 802.15.6 standard to provide a tool for evaluation and analysis of this standard in various channel conditions and situations. We have tried, through the main contributions made in this thesis, to address the shortcomings noted in existing work as follows: the first contribution concerns an evaluation of the performance of the IEEE 802.15.6 standard using numerous queue management strategies, in a realistic medical setting (home monitoring of a patient with a heart problem). The second contribution proposes an LLQ (Low Latency Queuing) queue management model as a complement to the CSMA/CA protocol to efficiently meet the requirements of the standard in terms of Quality of Service (QoS) for certain types of applications.The third contribution deals with the proposal of an analytical model allowing the study of the CSMA/CA access scheme of the IEEE 802.15.6 standard, in terms of latency and packet delivery rate under the assumption that WBANs are composed of heterogeneous nodes and that each of them generates heterogeneous traffic in terms of priority.The last contribution proposes a security protocol called "Server-Based Secure Key Management for the IEEE 802.15.6 standard" (SBSKM) that allows the standard to address the vulnerability of impersonation attacks, by including a trusted server, responsible for the creation, initialization, and distribution of encryption keys and their renewal, as well as to guarantee the identity of sensors joining the network.Keywords: Body Area Networks (WBANs), IEEE 802.15.6 standard, renewal reward process, priority queues, and impersonation attacks

The rationale for a telemedicine system is the use of Information and Communications Technology (ICT) for the remote transmission of biomedical data and the remote control of biomedical equipment, in order to improve the provided health service. The integration of Wireless Body Area Networks (WBANs) in telemedicine systems does not only achieve significant improvements in the patient’s healthcare, but also enhances their quality of life. However, the potential benefits provided by these networks are limited by the energy constraints imposed when traditional batteries are used as the power source, since the replacement or recharging of these is not always an easy task. To that end, harvesting energy from the human environment can be a promising solution to the aforementioned problems. In this context, it is important to design efficient energy-aware medium access and resource management schemes to exploit the benefits of energy harvesting while guaranteeing the Quality of Service (QoS) in the network. This dissertation provides a contribution to the design and evaluation of novel solutions focused on energy-aware resource management for WBANs powered by human energy harvesting. In particular, our proposals are oriented to solve the problems caused by the differences in energy levels experienced by nodes due to their power supply by energy harvesting. The main thesis contributions are divided into two parts. The first part presents HEH-BMAC, an energy-aware hybrid-polling Medium Access Control (MAC) protocol for WBANs powered by human energy harvesting. HEH-BMAC is designed to provide medium access taking into account the capabilities of each node with respect to their energy profile. HEH-BMAC combines two types of access mechanisms, i.e., reserved polling access and probabilistic random access, in order to adapt the network operation to the types of human energy harvesting sources. The HEH-BMAC performance in terms of normalized throughput and energy efficiency is assessed by means of extensive computer-based simulations, revealing a good adaptation to potential changes in the energy harvesting rate, packet inter-arrival time and network size. HEH-BMAC has been proven to outperform IEEE 802.15.6 Standard for WBANs in terms of normalized throughput and energy efficiency, as the number of nodes increases under the same conditions of energy harvesting. The second part of the thesis is dedicated to the design and evaluation of PEH-QoS, a Power-QoS control scheme for body nodes powered by energy harvesting. PEH-QoS is designed to use efficiently the harvested energy and ensure that all transmitted packets are useful in a medical context, hence substantially improving the offered QoS. The obtained results show that this scheme efficiently manages the data queue, thus improving the node operation and optimizing the data transmission, and also provides QoS, while maintaining the node in energy neutral operation state.<br>1. Introducción La razón de ser de un sistema de telemedicina es utilizar las tecnologías de la información y la comunicación (TIC) para la trasmisión remota de datos médicos, y el control de dispositivos biomédicos a distancia, con el objetivo de mejorar el servicio de salud prestado. Con la integración de las redes inalámbricas de área corporal (WBANs, por sus siglas en ingles) en los sistemas de telemedicina, no solamente se podría mejorar significativamente el cuidado de la salud del paciente, sino que también se conseguiría mejorar su calidad de vida. Las WBANs están compuestas por dispositivos médicos destinados a aplicaciones clínicas. Dichos dispositivos son llamados nodos corporales. En la WBAN cada nodo desempeña una importante función relacionada con el tratamiento, diagnostico o monitoreo de la salud del paciente. Los nodos corporales deben ser capaces de realizar sus tareas eficientemente e interaccionar con el cuerpo humano de una forma cómoda e indetectable para el paciente. Para tal fin, dichos nodos deben ser pequeños y ligeros para poder colocarlos dentro o sobre el cuerpo humano. Dichas características están íntimamente relacionadas con el tamaño de la batería y el consumo energético del nodo. La energía de la batería no solamente restringe al nodo en peso y tamaño sino que también lo hace en su periodo de vida, puesto que se trata de una fuente finita. Los problemas impuestos por la dependencia energética a este tipo de fuente de poder limitan los beneficios potenciales de las WBANs. Además, cambiar o recargar la batería no siempre es factible, ya que esto podría poner en riesgo la vida del paciente o causar daños al mismo nodo. La más innovadora y prometedora técnica para solucionar los problemas relacionados a la energía de las baterías es la captación de energía del entorno humano. Usando captadores de energía, un BN podría aprovechar fenómenos físicos o químicos (ejemplo: calor, luz, movimiento, vibraciones, etc.) en el cuerpo humano para convertirlos en energía eléctrica. El proceso de captación de energía entrega pequeñas cantidades de energía y es dependiente de la clase, disponibilidad de la fuente y la localización del nodo en el cuerpo humano. La idea de una WBAN que trabaje en sinergia con el cuerpo humano es sumamente alentadora. Sin embargo, ciertas consideraciones deben ser tomadas en cuenta para mantener un nivel aceptable de calidad de servicio (QoS, por sus siglas en ingles) en una WBAN alimentada por captación de energía. Los requerimientos de QoS son más exigentes en las WBANs en comparación a las tradicionales redes de sensores inalámbricos (WSNs, por sus siglas en ingles). En WBAN, la QoS es una demanda fundamental por lo tanto la maximización del rendimiento, la reducción del retardo y la extensión de la vida de la red son algunos de los principales retos a alcanzar. En redes alimentadas por baterías, el principal propósito del control del acceso al medio (MAC) es el de prolongar la vida de la red. Por otra parte, en redes alimentadas por captación de energía el principal objetivo es maximizar el rendimiento utilizando la energía disponible. Mediante la captación de energía, se podría extender la vida de la red, pero otras métricas de QoS podrían ser degradadas (ejemplo: rendimiento, retardo, pérdida de paquetes de datos, etc.). Esta tesis ofrece una contribución al diseño y evaluación de novedosas soluciones enfocadas a la gestión de recursos, para WBANs alimentadas por captación de energía (HEH-WBANs, por sus siglas en ingles), de una forma energéticamente consciente. En particular, nuestras propuestas están orientadas a resolver los problemas causados por las diferencias en los niveles de energía que experimentan los nodos debido a sus fuentes de captación. Las principales contribuciones de esta tesis se dividen en dos partes. La primera parte presenta HEH-BMAC, un protocolo híbrido, energéticamente consciente, para el control del acceso al medio de los nodos en este tipo de WBANs. HEH-BMAC está diseñada para proporcionar acceso al medio teniendo en cuenta las capacidades de cada nodo con respecto a sus características energéticas. HEH-BMAC combina de forma dinámica dos tipos de mecanismos de acceso, acceso reservado (basado en identificación de usuario) y acceso aleatorio (basado en probabilidad de contención), con el fin de adaptar el funcionamiento de la red a los tipos de fuentes de captación de los nodos. El funcionamiento del protocolo HEH-BMAC, es evaluado a través de extensas simulaciones por ordenador utilizando las métricas de rendimiento normalizado y eficiencia energética. Los resultados obtenidos en estas pruebas, muestran que nuestro protocolo tiene una buena adaptación a cambios potenciales en las velocidades de captación de energía, frecuencia de arribo de los paquetes de datos, y en el tamaño de la red. La segunda parte de la tesis está dedicada al diseño y evaluación de PEH-QoS, un esquema de control de potencia y QoS para nodos corporales que estén alimentados por captación de energía. PEH-QoS está diseñado para el uso eficiente de la energía captada y asegurar que todos los paquetes de datos trasmitidos sean útiles en el contexto médico, por lo tanto mejorando sustancialmente la QoS ofertada. Los resultados obtenidos muestran que este esquema gestiona eficientemente la cola de datos, mejora la operación del nodo, optimiza la trasmisión de datos, y provee QoS, mientras mantienen al nodo en estado de operación neutral. 2. Objetivos La planificación, el desarrollo, y la realización de esta tesis doctoral persiguen el siguiente objetivo: Diseño y desarrollo de soluciones energéticamente eficientes y conscientes, destinadas a la gestión de recursos que garanticen los requisitos de calidad de servicio de las aplicaciones médicas en WBANs alimentadas por captación de energía en el entorno humano. Al lograr el objetivo antes mencionado, esta tesis constituirá una contribución al avance de la WBANs alimentadas por captación de energía en el entorno humano en términos de una gestión eficiente de su energía enfocada en mejor la calidad de servicio. Para afrontar con éxito el objetivo general, los siguientes objetivos específicos tuvieron que ser también cumplidos: 1. Proporcionar un una amplia revisión del estado del arte en las áreas de protocolos MAC para WBANs y en captación de la energía en el entorno humano. 2. Proponer y evaluar un protocolo MAC consciente de la energía, capaz de adaptar el funcionamiento de la red a la naturaleza aleatoria y variable en el tiempo de las fuentes de captación de energía en el entorno humano. 3. Diseñar y desarrollar un esquema de control que permita el uso óptimo de la escasa energía recogida por un nodo corporal alimentado por captación de energía en el cuerpo humano, con el fin de mejorar la calidad de servicio prestados. 4. Evaluar los resultados de nuestras propuestas y compararlos con sistemas estándares de referencia utilizando diferentes métricas de calidad de servicio. 3. Resultados a) HEH-BMAC: HYBRID POLLING MAC PROTOCOL FOR WIRELESS BODY NETWORKS OPERATED BY HUMAN ENERGY HARVESTING. Tomando en cuenta los últimos avances en las áreas de WBANs y en captación de energía, propusimos un protocolo MAC hibrido al cual llamamos HEH-BMAC. HEH-BMAC es un protocolo de acceso al medio, el primero dentro de nuestro conocimiento, diseñado para WBANs alimentadas por captación de energía del entorno humano. La principal característica de HEH-BMAC es que es un protocolo energéticamente consciente en condiciones de captación de energía, ya que el funcionamiento de cada nodo es adaptado dinámicamente dependiendo de su nivel de energía. En particular nuestro protocolo tiene las siguientes características: i) Este ofrece dos niveles de prioridades a través de la combinación de dos mecanismos diferentes de acceso al medio. El primer mecanismo de acceso es el de identificación de usuario (ID-POLLING) para acceso reservado, dicho mecanismo está pensado para nodos con captación de energía predecible (por ejemplo: Generadores piezoeléctricos que aprovechan los latidos del corazón o de los movimientos respiratorios) o nodos con alta prioridad (por ejemplo: Electrocardiógrafo, electroencefalógrafo, etc.). El segundo método de acceso es por probabilidad de contención (PC-ACCESS) para acceso aleatorio, este mecanismo está destinado para nodos alimentados con fuentes de captación de energía no predecible (por ejemplo: generadores termoeléctricos sobre la piel, generadores piezoeléctricos que aprovechan la locomoción humana, etc.) o nodos con prioridad normal (por ejemplo: termómetros, flujo sanguíneo, etc.). ii) Los periodos de tiempo para los accesos al medio, ya sea ID-POLLING o PC-ACCESS, son ajustados dinámicamente de acuerdo a los niveles energéticos de los nodos. Dicha asignación es realizada a través de un algoritmo ejecutado en el nodo corporal coordinador de la red (BNC). El BNC ejecuta el algoritmo DYNAMIC SCHEDULE ALGORITHM, pudiendo de esta forma manejar la comunicación de todos los nodos que forman la WBAN. Dicho algoritmo contrala de manera conjunta ambos tipos de acceso a través de una lista dinámica para los nodos en ID-POLLING y a través de un algoritmo de actualización del valor de umbral para la contención en los nodos en PC-Access. Los nodos en ID-POLLING acceden al medio de forma expedita y los nodos en PC-Access tienen un acceso probabilístico. iii) Al ejecutarse el acceso al medio de forma dinámica, HEH-BMAC permite la adición y remoción de nodos en la WBAN, puesto que la actualización de la lista dinámica y del algoritmo de actualización del valor umbral de contención son ajustados dependiendo de la respuesta de la cantidad de nodos que están funcionando en la red. RESULTADOS 1: Primeramente brindamos un comprensivo estado del arte, además expusimos nuestros criterios de diseño y explicamos detalladamente cómo funciona nuestra propuesta. Las pruebas realizadas a nuestro protocolo MAC fueron simuladas (a través de un simulador que desarrollamos en MATLAB) con diferentes velocidades de captación de energía. Las métricas utilizadas para la evaluación de nuestra propuesta fueron eficiencia energética y rendimiento normalizado. Como resultado de este estudio pudimos comprobar la buena adaptación que posee HEH-BMAC a diferentes condiciones energéticas, tiempos de arribo de datos y flexibilidad al agregar o remover nodos en la red. Las pruebas las realizamos con cuatro diferentes velocidades de trasmisión de datos. Como resultado de esta investigación, realizamos el trabajo: E. Ibarra, A. Antonopoulos, E. Kartsakli and C. Verikoukis., “HEH-BMAC: Hybrid Polling MAC Protocol for Wireless Body Area Networks Operated by Human Energy Harvesting”. Journal of Telecommunication Systems, Modeling, Analysis, Design and Management. Special Issue on: Research Advances in Energy Efficient MAC protocols for WBANs. (Accepted, December 2012). El siguiente paso en nuestro proceso investigativo fue comparar el desempeño de nuestro protocolo HEH-BMAC con el recién publicado (29 de febrero de 2012) protocolo IEEE 802.15.6 es el protocolo de red para redes de sensores corporales del IEEE diseñado para comunicación dentro y fuera del cuerpo humano. Tomando en cuenta que el protocolo de la IEEE 802.15.6. no fue diseñado para trabajar en redes WBANs alimentadas por captación de energía, escogimos un escenario en que ambos protocolos tuvieran suficiente energía para trabajar correctamente. Comparamos dos configuraciones del protocolo acceso CSMA/CA del IEEE con nuestra propuesta HEH-BMAC. La comparación entre ambos protocolos se realizó a través de las métricas rendimiento normalizado y eficiencia energética. RESULTADOS 2: Como resultado de este trabajo comprobamos que nuestro protocolo HEH-BMAC tiene mejor rendimiento normalizado y comportamiento que el del IEEE 802.15.6 en condiciones de captación de energía. Además, nuestro protocolo tiene un nivel alto de eficiencia energética (ver figura 1) cuando se aumentan el número de nodos a la WBANs, en comparación al protocolo de la IEEE 802.15.6. Como resultado de esta investigación, realizamos el trabajo: E. Ibarra, A. Antonopoulos, E. Kartsakli and C. Verikoukis, “Energy Harvesting Aware Hybrid MAC Protocol for WBANs”, IEEE HEALTHCOM 2013, October 2013, Lisbon, Portugal. b) JOINT POWER-QoS CONTROL SCHEME FOR ENERGY HARVESTING BODY SENSOR NODES En este trabajo desarrollamos un esquema de control para los BNs alimentados por captación de energía con el fin de mejorar la calidad de servicio (QoS) prestada por cada nodo. Dicho esquema lo hemos llamado esquema de control PEH-QoS. PEH-QoS está formado por tres sub-módulos que interaccionan entre sí con el objetivo de conseguir el mejor QoS posible. Los sub-módulos que componen dicho esquema son: i. PHAM: POWER-EH AWARE MANAGEMENT SUB-MODULE: El objetivo del mismo es realizar un uso óptimo de la escasa energía recabada. Solo realizando las funciones de detección o de trasmisión cuando se tenga la cantidad suficiente de energía para completar los procesos. Controlando el consumo energético del BN para mantenerlo en un estado de Operación Energéticamente Neutral (Estado ENO). El estado ENO, es definido como una condición en que el nodo gasta menos o igual cantidad de energía que la recolectada del ambiente, manteniendo un rendimiento deseado. ii. DQAC: DATA QUEUE AWARE CONTROL SUB-MODULE: El objetivo de este sub-modulo es de estabilizar la cola de datos en condiciones de captación de energía. El principal función de DQAC es evitar la saturación de la cola de datos y mantener la validez clínica de la información almacenada por medio de la eliminación de paquetes que han perdido relevancia y actualizando la cola de datos. iii. PASS: PACKET AGGREGATOR/SCHEDULING SYSTEM SUB-MODULE: La función de este sub-modulo es la de optimizar cada trasmisión realizada, enviando en cada proceso de comunicación la mayor cantidad de paquetes posibles. Esto se realiza a través de un sistema de agregación de paquetes dependiendo de la energía disponible (PHAM) y del estado de la cola de datos (DQAC). RESULTADOS 3: Comparamos un BN aplicándole nuestra propuesta, con el mismo nodo sin PEH-QoS. Ambos fueron comparados en las mismas condiciones de captación de energía. Como resultado de dicho estudio obtuvimos que nuestro sistema supero sustancialmente al nodo de referencia en cuanto a rendimiento normalizado, eficiencia energética, perdida de paquetes de datos, y retardo promedio end-to-end. Además, gracias a PEH-QoS alcanzo niveles altos de eficiencia en la detección de eventos y en la eficiencia de almacenaje de datos. Como resultado de esta investigación, realizamos el trabajo: E. Ibarra, A. Antonopoulos, E. Kartsakli and C. Verikoukis, “Joint Power-QoS Control Scheme for Energy Harvesting Body Sensor Nodes”, IEEE ICC 2014, June 2014, Sydney, Australia. 4. Discusiones y Conclusiones HEH-BMAC asigna períodos de tiempo, tanto para ID-POLLING y el PC- ACCESS a través del DYNAMIC SCHEDULE ALGORITHM. La distribución del tiempo se llevan a cabo de una manera dinámica, logrando el uso óptimo del medio. Todos los nodos del WBAN son energéticamente conscientes, es decir, tratan de acceder al medio sólo si tienen los paquetes de datos a transmitir y si tienen suficiente energía para terminar con éxito una secuencia de transmisión. La combinación de estos dos modos de acceso y el DYNAMIC SCHEDULE ALGORITHM, no sólo mejora el rendimiento normalizado y la eficiencia de energía del sistema, sino que también permite la adaptación de la red a los cambios en el número de nodos, el tiempo entre llegadas de datos y la tasa en que se capta energía del ambiente. Por último, para completar nuestro estudio de investigación acerca de HEH-BMAC, se comparó el rendimiento normalizado y la eficiencia energética de nuestro protocolo con el protocolo estándar IEEE 802.15.6. En comparación con el estándar IEEE 802.15.6, HEH-BMAC logra una ganancia de hasta un 20% en la eficiencia de energía y hasta un 56% en el rendimiento normalizado. Además, los resultados mostraron que nuestro protocolo puede adaptarse mejor a un aumento potencial en el número de nodos en la red, en comparación con el estándar en las mismas condiciones de captación de energía. El proceso de captación de energía introduce variaciones en los niveles de energía de los BNs (debido principalmente a las características y la disponibilidad de las fuentes que se captarán) que afectan directamente a su funcionamiento, reduciendo su rendimiento y la eficiencia de las tareas realizadas. Pequeñas cantidades de energía que pueden ser captadas del cuerpo humano deben utilizarse de una manera óptima y eficiente para evitar que se desperdicie. PEH-QoS aborda de manera eficiente estos problemas con el fin de mejorar la calidad de servicio proporcionadas. Los resultados obtenidos mostraron que cuando se aplica PEH-QoS, la eficiencia de energía del nodo se incrementa de 0,78 MB / J hasta 39,6 MB / J (≈ 50 veces), mientras la pérdida de paquetes se reduce hasta 0,39% y el promedio de retardo hasta 130 ms. Nuestro enfoque mejora sustancialmente la calidad de servicio prestado, mientras que también logra una mayor eficiencia de detección y de almacenamiento de datos, lo que demuestra que las técnicas basadas en la conciencia de la energía son excelentes herramientas para mejorar el rendimiento de la BN. En conclusión, los dos esquemas propuestos, HEH-BMAC y PEH QoS, han introducido importantes mejoras en el rendimiento del sistema, tanto a nivel de las HEH-WBANs y como de los BNs.

One key solution to provide affordable and proactive healthcare facilities to overcome the fast world population growth and a shortage of medical professionals is through health monitoring systems capable of early disease detection and real-time data transmission leading to considerable improvements in the quality of human life. Wireless body area networks (WBANs) are proposed as promising approaches to providing better mobility and flexibility experience than traditional wired medical systems by using low-power, miniaturised sensors inside, around, or off the human body and are employed to monitor physiological signals. However, the design of reliable and energy efficient in-body communication systems is still a major research challenge since implant devices are characterised by strict requirements on size, energy consumption and safety. Moreover, there is still no agreement regarding QoS support in WBANs. The first part of this work concentrates on the design and performance evaluation of WBAN communication systems involving the ‘in-body to in-body’ and ‘in-body to on-body’ scenarios. The essential step is to derive the statistical WBAN path loss (PL) models, which characterise the signal propagation energy loss transmitting via intra-body region. Moreover, from the point of view of human body safety evaluation, the obtained specific absorption rate (SAR) values are compared with the latest Institute of Electrical and Electronics Engineers (IEEE) 802.15.6 Task Group technical standard and the International Commission on Non-Ionizing Radiation Protection (ICNIRP) safety guidelines. Link budget analysis is then presented using a range of energy-efficient modulation schemes, and the results are given including the transmission distance, data rate and transmitting power in individual sections. On the other hand, major quality of service (QoS) support challenges in WBANs are discussed and investigated. To achieve higher lifetime and lower network energy consumption, different data routing protocol methods, including incremental relaying and the two-relay based routing technique are taken into account. A set of key QoS metrics for linear mathematical models is given along with the related subjective functions. The incremental relaying routing protocol promises significant enhancements in in-body WBAN network lifetime by minimising the overall communication distance while the two-relay based routing method achieves better performance in terms of emergency data transmission and high traffic condition, QoS-aware WBANs design. Moreover, to handle real-time high data transmission applications such as capsule endoscope image transmission, a flexible QoS-aware wireless body area sensor networks (WBASNs) model is proposed and evaluated that can bring novel solutions for a realistic multi-user hospital environment regarding information packet collision probability, manageable numbers of sensor nodes and a wide range of data rates.

The advent of wireless body area networks (WBANs) and their use in a wide range of applications from consumer electronics to military purposes, dictates the need to investigate to the behaviour of antennas and wave propagation on the body in depth. Although this area has been extensively studied in the past decade, some issues are still not satisfactorily solved for communication systems for WBANs at ISM bands and UWB such as compact and high efficiency antenna design, privacy and security, interference mitigation and achieving high data rates. This thesis proposed an alternative wireless solution for body area networks by adopting 60 GHz radio. On-body channels at 60 GHz have been characterised using monopole and horn antennas. Horn antennas achieve significantly improved path gain in the stable channels but are susceptible to shadowing in the mobile channels due to body movements. However, interference mitigation and covertness for 60 GHz WBANs at the physical layer are improved due to high attenuation of 60 GHz signals. Significant increase of carrier-to-interference ratio is observed for 60 GHz WBANs compared to 2.45 GHz. A model of estimating the maximum detection distance at a threshold probability for detecting a WBAN wearing soldier in a battlefield is proposed. Fixed-beam directional antennas and reconfigurable antennas are designed for 60 GHz WBANs and channel measurements using these antennas are conducted. Results show beam-reconfigurability of the antenna improves the link performance compared to fixed-beam antennas at 60 GHz.

Pour réduire la consommation d'énergie due aux transmissions radio dans les réseaux de capteurs sans fil, nous proposons une nouvelle approche associant les techniques de précodage MIMO et de relais, appelé précodage distribué max-dmin (DMP). Considérant une source et un relais avec une antenne chacun, et une destination disposant de deux antennes, nous déployons un système MIMO précodé virtuel 2 × 2. Dans ce contexte, nous étudions deux techniques de relais Amplify and Forward (AF) et Decode and Forward (DF). Des comparaisons en termes de taux d'erreur et d'efficacité énergétique par rapport aux systèmes plus classiques comme les codes spatio-temporels distribués ou les combinaisons à gain maximal montrent que notre système est intéressant pour des distances de transmission moyennes (à partir de 16 mètres). Toujours dans l'objectif de maximiser l'efficacité énergétique, nous proposons une allocation de puissance sur les nœuds source et relais. Pour cela, nous dérivons analytiquement les performances du système précodage distribué max-dmin selon le mode AF et DF. Enfin,pour améliorer les performances des systèmes avec décodage au relais (DF), nous proposons un nouveau récepteur (à la destination) qui tient compte des erreurs éventuelles au niveau du relais<br>Among various cooperative techniques aiming to reduce power consumption for transmissions between Wireless Body Area Networks (WBAN) and base stations, we present a new approach, named distributed max-dmin precoding (DMP), combining MIMO precoding techniques and relay communications. This protocol is based on the deployment of a virtual 2 × 2 max-dmin precoding over one source, one forwarding relay, both equipped with one antenna and a destination involving 2 antennas. In this context, two kinds of relaying, amplify and forward (AF) or decode and forward (DF) protocols, are investigated. The performance evaluation in terms of Bit-Error-Rate (BER) and energy efficiency are compared with non cooperative techniques and the distributed space time block code (STBC) scheme. Our investigations show that the DMP takes the advantage in terms of energy efficiency from medium transmission distances (after 10 meters). In order to maximise the energy efficiency, we propose a power allocation over the source and the relay. Thus, we derive the performance of our system, both for AF and DF, analytically. To further increase the performance of DF cooperative schemes, we also propose to design a new decoder at the destination that takes profit from side information, namely potential errors at the relay

L’amélioration de la qualité et de l’efficacité en santé est un réel enjeu sociétal. Elle implique la surveillance continue des paramètres vitaux ou de l’état mental du sujet. Les champs d’applications sont vastes : l’application la plus importante est la surveillance des patients à distance. Les avancées en micro-électronique, capteurs et réseaux sans-fil permettent aujourd’hui le développement de systèmes ambulatoires performants pour le monitoring de paramètres physiologiques, capables de prendre en compte d’importantes contraintes techniques : forte intégration pour la réduction de la taille et faible consommation pour une plus grande autonomie [1]. Cependant, la conception de ce type de réseaux de capteurs médicaux WBANs (Wireles Body Area Networks) se heurte à un certain nombre de difficultés techniques, provenant des contraintes imposées par les capacités réduites des capteurs individuels : basse puissance, énergie limitée et faible capacité de stockage. Ces difficultés requièrent des solutions différentes, encore très embryonnaires, selon l’application visée (monitoring à but médical). La forte mobilité et le changement rapide de la topologie du réseau dévoilent un verrou scientifique et social. En outre, l’interférence de différents capteurs constituant le WBAN augmente la difficulté de la mise en place de ce type de réseaux. De nombreuses solutions dans la littérature ont été étudiées, comme nous allons illustrer dans ce manuscrit, néanmoins elles restent limitées. Nous nous intéresserons tout particulièrement à la gestion des interférences Intra- et Inter-WBAN, leur impacte sur la fiabilité des transmissions (des liens) et la durée de vie de ce type de réseaux. Plus précisément, nous abordons ces problématiques en se basant sur des modélisations théoriques et analytiques et avec une conception pratique des solutions proposées. Afin d’atteindre les objectifs cités ci-dessous, nous abordons quatre solutions : • Une gestion des interférences intra-WBAN • Une gestion coopérative des interférences Inter-WBAN • Une gestion non coopérative des interférences, Inter-WBAN • Une gestion des interférences WBAN dans un contexte IoT Dans la première partie de cette thèse et afin de répondre en partie aux problèmes de gestion des interférences Intra-WBAN. Nous présentons deux mécanismes pour le WBAN : (a) CFTIM qui alloue dynamiquement des slots et des canaux dit- stables (avec un taux d’interférences le bas possible dans le temps) pour réduire les interférences intra-WBAN. (b) IAA ajuste dynamiquement la taille du superframe et limite le nombre de canaux à 2 pour abaisser les interférences Intra-WBAN et ainsi économiser l’énergie. Une validation avec un model probabiliste est proposé afin de valider théoriquement l’efficacité de notre solution. Les résultats de la simulation démontrent l’efficacité du CFTIM et de l’IAA en termes de réduction de la probabilité d’interférence, l’extension de la durée de vie du réseau et l’amélioration du débit et de la fiabilité des transmissions. Notre seconde contribution, propose une gestion coopératives des interférences Inter-WBAN en utilisant des codes orthogonaux. Motivé par un approvisionnement temporel distribué basé sur la norme [2] IEEE 802.15.6, nous proposons deux solutions. (a) DTRC qui fournit à chaque WBAN les connaissances sur les superframes qui se chevauchent. Le second, (b) OCAIM qui attribue des codes orthogonaux aux capteurs appartenant à deux listes de groupe de capteur en interférences de deux WBAN différents (SIL). Les résultats démontrent qu’OCAIM diminue les interférences, améliore le débit et préserve la ressources énergétiques. La troisième partie nous a permis d’aborder la gestion des interférences, mais cette fois ci d’une manière non-coopérative en se basant sur l’affectation couple Slot/Canal. Plus précisément, nous proposons deux schémas basés sur les carrés latins. (...)<br>A Wireless Body Area Network (WBAN) is a short-range network that consists of a coordinator (Crd) and a collection of low-power sensors that can be implanted in or attached to the human body. Basically, WBANs can provide real-time patient monitoring and serve in various applications such as ubiquitous health-care, consumer electronics, military, sports, etc. [1]. As the license-free 2.4 GHz ISM band is widely used among WBANs and across other wireless technologies, the fundamental problem is to mitigate the resulting co-channel interference. Other serious problems are to extend the network lifetime and to ensure reliable transmission within WBANs, which is an urgent requirement for health-care applications. Therefore, in this thesis, we conduct a systematic research on a few number of research problems related to radio co-channel interference, energy consumption, and network reliability. Specifically, we address the following problems ranging from theoretical modeling and analysis to practical protocol design: • Intra-WBAN interference mitigation and avoidance • Cooperative inter-WBAN interference mitigation and avoidance • Non-cooperative inter-WBAN interference mitigation and avoidance • Interference mitigation and avoidance in WBANs with IoT Firstly, to mitigate the intra-WBAN interference, we present two mechanisms for a WBAN. The first is called CSMA to Flexible TDMA combination for Interference Mitigation, namely, CFTIM, which dynamically allocates time-slots and stable channels to lower the intra-WBAN interference. The second is called Interference Avoidance Algorithm, namely IAA that dynamically adjusts the superframe length and limits the number of channels to 2 to lower the intra-WBAN interference and save energy. Theoretically, we derive a probabilistic model that proves the SINR outage probability is lowered. Simulation results demonstrate the effectiveness and the efficiency of CFTIM and IAA in terms of lowering the probability of interference, extending network lifetime, improving throughput and reliability. Secondly, we address the problem of interference among cooperative WBANs through using orthogonal codes. Motivated by distributed time provisioning supported in IEEE 802.15.6 standard [2], we propose two schemes. The first is called Distributed Time Correlation Reference, namely, DTRC that provides each WBAN with the knowledge about which superframes overlap with each other. The second is called Orthogonal Code Allocation Algorithm for Interference Mitigation, namely, OCAIM, that allocates orthogonal codes to interfering sensors belonging to sensor interference lists (SILs), which are generated based on the exchange of power-based information among WBANs. Mathematically, we derive the successful and collision probabilities of frames transmissions. Extensive simulations are conducted and the results demonstrate that OCAIM can diminish the interference, improve the throughput and save the power resource. Thirdly, we address the problem of co-channel interference among non-cooperative WBANs through time-slot and channel hopping. Specifically, we propose two schemes that are based on Latin rectangles. The first is called Distributed Algorithm for Interference mitigation using Latin rectangles, namely, DAIL that allocates a single channel to a timeslot combination to each sensor to diminish inter-WBAN interference and to yield better schedules of the medium access within each WBAN. The second is called Channel Hopping for Interference Mitigation, namely, CHIM, which generates a predictable interference free transmission schedule for all sensors within a WBAN. CHIM applies the channel switching only when a sensor experiences interference to save the power resource. Furthermore, we present an analytical model that derives bounds on collision probability and throughput for sensors transmissions. (...)

In Time-of-Arrival (TOA) based indoor human tracking system, the human body mounted with the target sensor can cause non-line-of-sight (NLOS) scenario and result in significant ranging error. In this thesis, we measured the TOA ranging error in a typical indoor environment and analyzed sources of inaccuracy in TOAbased indoor localization system. To quantitatively describe the TOA ranging error caused by human body, we introduce a statistical TOA ranging error model for body mounted sensors based on the measurement results. This model separates the ranging error into multipath error and NLOS error caused by the on-body creeping wave phenomenon. Both multipath error and NLOS error are modeled as a Gaussian variable. The distribution of multipath error is only relative to the bandwidth of the system while the distribution of NLOS error is relative to the angle between human facing direction and the direction of Transmitter-Receiver, signal to noise ratio (SNR) and bandwidth of the system, which clearly shows the effects of human body on TOA ranging. An efficient way to fight against the TOA ranging error caused by human body is to employ site-specific channel models by using ray-tracing technology. However, existing ray-tracing softwares lack the propagation model that takes the effects of human body into account. To address that issue, this thesis presents a empirical model for near human body ultra-wideband (UWB) propagation channel that is valid for the frequency range from 3GHz to 8GHz. It is based on measurements conducted in a anechoic chamber which can be regarded as free space. The empirical model shows the joint propagation characteristics of the on body channel and the channel between body surface and external access point. It includes the loss of the first path, arrival time of the first path and the total pathloss. Models for all three aspects have been partitioned into two sections by a break point due to the geometrical property of human body and the creeping wave phenomenon. The investigation on first path behavior can be regarded as a theoretical basis of raytracing technique that takes the effects of human body into consideration.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 85-91).<br>In recently published integrated medical monitoring systems, a common thread is the high power consumption of the radio compared to the other system components. This observation is indicative of a natural place to attempt a reduction in system power. Narrowband receivers in-particular can enjoy significant power reduction by employing high-Q bulk acoustic resonators as channel select filters directly at RF, allowing down-stream analog processing to be simplified, resulting in better energy efficiency. But for communications in the ISM bands, it is important to employ multiple frequency channels to permit frequency-division-multiplexing and provide frequency diversity in the face of narrowband interferers. The high-Q nature of the resonators means that frequency tuning to other channels in the same band is nearly impossible; hence, a new architecture is required to address this challenge. A multi-channel ultra-low power OOK receiver for Body Area Networks (BANs) has been designed and tested. The receiver multiplexes three Film Bulk Acoustic Resonators (FBARs) to provide three channels of frequency discrimination, while at the same time offering competitive sensitivity and superior energy efficiency in this class of BAN receivers. The high-Q parallel resonance of each resonator determines the passband. The resonator's Q is on the order of 1000 and its center frequency is approximately 2.5 GHz, resulting in a -3 dB bandwidth of roughly 2.5 MHz with a very steep rolloff. Channels are selected by enabling the corresponding LNA and mixer pathway with switches, but a key benefit of this architecture is that the switches are not in series with the resonator and do not de-Q the resonance. The measured 1E-3 sensitivity is -64 dBm at 1 Mbps for an energy efficiency of 180 pJ/bit. The resonators are packaged beside the CMOS using wirebonds for the prototype.<br>by Phillip Michel Nadeau.<br>S.M.

Wireless body area networks (WBANs) have tremendous potential to benefit from wireless communication technology and are expected to make sweeping changes in the future human health care and medical fields. While the prospects for WBAN products are high, meeting required device performance with a meager amount of power consumption poses significant design challenges. In order to address these issues, IEEE has recently developed a draft of IEEE 802.15.6 standard dedicated to low bit-rate short-range wireless communications on, in, or around the human body. Commercially available SoC (System-on-Chip) devices targeted for WBAN applications typically embed proprietary wireless transceivers. However, those devices usually do not meet the quality of service (QoS), low power, and/or noninterference necessary for WBAN applications, nor meet the IEEE standard specifications. This dissertation presents a design of low-power RF front-end conforming to the IEEE standard in Medical Communication Service (MICS) band of 402-405 MHz. First, we investigated IEEE 802.15.6 PHY specifications for narrow band WBAN applications. System performance analysis and simulation for an AWGN (additive white Gaussian noise) channel was conducted to obtain the BER (bit error rate) and the PER (packet error rate) as the figure of merit. Based on the system performance study, the link budget was derived as a groundwork for our RF front-end design. Next, we examined candidate RF front-end architectures suitable for MICS applications. Based on our study, we proposed to adopt a direct conversion transmitter and a low-IF receiver architecture for the RF front-end. An asynchronous wake-up receiver was also proposed, which is composed of a carrier sensing circuit and a serial code detector. Third, we proposed and implemented low-power building blocks of the proposed RF front-end. Two quadrature signal generation techniques were proposed and implemented for generation of quadrature frequency sources. The two quadrature voltage controlled oscillators (QVCOs) were designed using our proposed current-reuse VCO with two damping resistors. A stacked LNA and a down-conversion mixer were proposed for low supply and low power operation for the receiver front-end. A driver amplifier and an up-conversion mixer for the transmitter front-end were implemented. The proposed driver amplifier uses cascaded PMOS transistors to minimize the Miller effect and enhance the input/output isolation. The up-conversion mixer is based on a Gilbert cell with resistive loads. Simulation results and performance comparisons for each designed building block are presented. Finally, we present a case study on a direct VCO modulation transmitter and a super-regenerative receiver, which can also be suitable for an MICS transceiver. Several crucial building blocks including a digitally-controlled oscillator (DCO) and quench signal generators are proposed and implemented with a small number of external components.<br>Ph. D.

Mobile healthcare offers continuous monitoring of people’s health conditions while they are doing their daily activities. This service is realized using body area networks (BAN) that facilitate ubiquitous monitoring by eliminating wires between body nodes and the system that collect health signals for diagnostics by medical practitioners. To keep a constant flow of medical data over a BAN, body nodes have to have reliable and low-delay access to the medium when they have a sample to report. In an investigation of a proper medium access control (MAC) scheme for BANs, the IEEE 802.15.4 synchronous Beacon-Enabled mode, which is recommended for low-rate wireless personal area networks, is studied. Because of a tight network synchronization requirement of the 802.15.4 MAC, which is hard to maintain in coexistence with heterogeneous networks, an interference-aware MAC for opportunistic access to the shared medium is proposed. The Centralized BAN Access Scheme (CBAS) resolves medium access contention within a BAN while protecting BAN transmissions from being interfered by coexistent networks. Feasibility of CBAS for handling pervasive monitoring and prompt medium access requirements is experimentally investigated over the unlicensed 2.4GHz band. For channel sensing in the experimental setup, the proposed dual-spectrum-sensing strategy is applied to improve robustness of channel state detection without making any assumption about technologies of detected transmissions. Regarding diverse service requirements of collocated BANs, a distributed channel selection strategy, for integration to CBAS, is proposed for quality of service (QoS) provisioning. The kth-MAB strategy establishes a QoS-aware platform over which radio resources are distributed amongst BANs proportional to their QoS levels determined by the health conditions of the respective subject. Considering body nodes’ low power transmissions and continuously changing body posture, an adaptive cross layer design is proposed to capture BAN topology dynamism in packet routing over a BAN. In collaboration with the receiver-initiated CBAS, each body node extracts local information about its connectivity with other nodes within a BAN to contribute in improvement of the network’s packet delivery. By opportunistic capturing of high quality on-body links per packet transmission, this topology-adaptive scheduling scheme improves reliability while minimizing the need for multi-hop cooperative transmissions.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate

Wireless Body Area Network (WBAN) facilitates efficient and cost-effective e-health care and well-being applications. The WBAN has unique challenges and features compared to other Wireless Sensor Networks (WSN). In addition to battery power consumption, the vulnerability and the unpredicted channel behavior of the Medium Access Control (MAC) layer make channel access a serious problem. MAC protocols based on Time Division Multiple Access (TDMA) can improve the reliability and efficiency of WBAN. However, conventional static TDMA techniques adopted by IEEE 802.15.4 and IEEE 802.15.6 do not sufficiently consider the channel status or the buffer requirements of the nodes within heterogeneous contexts. Although there are some solutions that have been proposed to alleviate the effect of the deep fade in WBAN channel by adopting dynamic slot allocation, these solutions still suffer from some reliability and energy efficiency issues and they do not avoid channel deep fading. This thesis presents novel and generic TDMA based techniques to improve WBAN reliability and energy efficiency. The proposed techniques synchronise nodes adaptively whilst tackling their channel and buffer status in normal and emergency contexts. Extensive simulation experiments using various traffic rates and time slot lengths demonstrate that the proposed techniques improve the reliability and the energy efficiency compared to the de-facto standards of WBAN, i.e. the IEEE 802.15.4 and the IEEE 802.15.6. In normal situations, the proposed techniques reduce packet loss up to 61% and 68% compared to the IEEE 802.15.4 and IEEE 802.15.6 respectively. They also reduce energy consumption up to 7.3%. In emergencies, however, the proposed techniques reduce packets loss up to 63.4% and 90% with respect to their counterparts in IEEE 802.15.4 and 802.15.6. The achieved results confirm the significant enhancements made by the developed scheduling techniques to promote the reliability and energy efficiency of WBAN, opening up promising doors towards new horizons and applications.

A Wireless Body Sensor Network (WBSN) consists of several biological sensors. WBSN can be employed to monitor patients’ medical conditions. Energy consumption and reliability are critical issues in WBSNs, as the nodes that are placed near the sink node consume more energy. All biomedical packets are aggregated through these nodes, forming a bottleneck zone. The nodes usually use small batteries and in the case of implantable devices; it is important to prolong battery life. The main consideration of this thesis is the reduction of energy consumption of WBSN devices (sensor nodes) and the successful delivery of biomedical data at sink nodes based on medium access control (MAC) protocol IEEE 802.15.4 standard. A novel mathematical model for WBSN topology is proposed in this thesis to explain the deployment of and connection between biosensor nodes, simple relay nodes, network coding relay nodes, and the sink node. Also, the Coordinated Duty Cycle Algorithm (CDCA) is the proposed novel approach which is adopted for the body area network. CDCA achieves energy savings for nodes through the implementation of mechanisms such as the selection of superframe order based on real traffic and the priority of the nodes in the WBSN, and the calculation of the Coordinated Duty Cycle (CDC). In addition, RLNC is employed to achieve the required level of reliability in WBSNs and delivery of packets through the calculation of the probability of successful reception at the sink node. This research identified that energy consumption in WBSNs is affected by the following parameters: the distances and locations of the nodes on the human body, WBSN topology, employing relay nodes, the propagation model such as the line of sight (LOS) and the non-line of sight (NLOS). Simulation results are presented to show that CDCA improves the energy consumption of biosensor nodes. Also, the results from a comparative analysis of RLNC and XOR NC show that RLNC provides a higher probability of successful reception of data packets at the sink node than the XOR NC technique. Overall, this work demonstrates a new scheme for achieving energy reductions for the biosensor nodes in WBSNs which operate at low data rate; also, it achieves the required level of reliability in WBSNs.

This dissertation will present several novel techniques that use cooperation and diversity to improve the performance of multihop Wireless Sensor Networks, as measured by throughput, delay, and reliability, beyond what is achievable with conventional error control technology. We will investigate the applicability of these new technologies to Wireless Body Area Networks (WBANs) an important emerging class of wireless sensor networks. WBANs, which promise significant improvement in the reliability of monitoring and treating people's health, comprise a number of sensors and actuators that may either be implanted in vivo or mounted on the surface of the human body, and which are capable of wireless communication to one or more external nodes that are in close proximity to the human body. Our focus in this research is on enhancing the performance of WBANs, especially for emerging real-time in vivo traffic such as streaming real-time video during surgery. Because of the nature of this time-sensitive application, retransmissions may not be possible. Furthermore, achieving minimal energy consumption, with the required level of reliability is critical for the proper functioning of many wireless sensor and body area networks. Additionally, regardless of the traffic characteristics, the techniques we introduce strive to realize reliable wireless sensor networks using (occasionally) unreliable components (wireless sensor nodes). To improve the performance of wireless sensor networks, we introduce a novel technology Cooperative Network Coding, a technology that synergistically integrates the prior art of Network Coding with Cooperative Communications. With the additional goal of further minimizing the energy consumed by the network, another novel technology Cooperative Diversity Coding was introduced and is used to create protection packets at the source node. For representative applications, optimized Cooperative Diversity Coding or Cooperative Network Coding achieves ≥ 25% energy savings compared to the baseline Cooperative Network Coding scheme. Cooperative Diversity Coding requires lees computational complexity at the source node compared to Cooperative Network Coding. To improve the performance and increase the robustness and reliability of WBANs, two efficient feedforward error-control technologies, Cooperative Network Coding (CDC) and Temporal Diversity Coding (TDC), are proposed. Temporal Diversity Coding applies Diversity Coding in time to improve the WBAN's performance. By implementing this novel technique, it is possible to achieve significant improvement (50%) in throughput compared to extant WBANs. An example of an implementation of in vivo real-time application, where TDC can improve the communications performance, is the MARVEL (Miniature Anchored Robotic Videoscope for Expedited Laparoscopy) research platform developed at USF. The MARVEL research platform requires high bit rates (100 Mbps) for high-definition transmission. Orthogonal Frequency Division Multiplexing (OFDM), a widely used technology in fourth generation wireless networks (4G) that achieves high transmission rates over dispersive channels by transmitting serial information through multiple parallel carriers. Combining Diversity Coding with OFDM (DC-OFDM) promises high reliability communications while preserving high transmission rates. Most of the carriers transport original information while the remaining (few) carriers transport diversity coded (protection) information. The impact of DC-OFDM can extend far beyond in vivo video medical devices and other special purpose wireless systems and may find significant application in a broad range of ex vivo wireless systems, such as LTE, 802.11, 802.16.

The continuous miniaturisation of sensors, as well as the progression in wearable electronics, embedded software, digital signal processing and biomedical technologies, have led to new usercentric networks, where devices can be carried in the user’s pockets, attached to the user’s body. Body-centric wireless communications (BCWCs) is a central point in the development of fourth generation mobile communications. Body-centric wireless networks take their place within the personal area networks, body area networks and sensor networks which are all emerging technologies that have a wide range of applications (such as, healthcare, entertainment, surveillance, emergency, sports and military). The major difference between BCWC and conventional wireless systems is the radio channels over which the communication takes place. The human body is a hostile environment from a radio propagation perspective and it is therefore important to understand and characterise the effects of the human body on the antenna elements, the radio channel parameters and, hence, system performance. This thesis focuses on the study of body-worn antennas and on-body radio propagation channels. The performance parameters of five different narrowband (2.45 GHz) and four UWB (3.1- 10.6 GHz) body-worn antennas in the presence of human body are investigated and compared. This was performed through a combination of numerical simulations and measurement campaigns. Parametric studies and statistical analysis, addressing the human body effects on the performance parameters of different types of narrowband and UWB antennas have been presented. The aim of this study is to understand the human body effects on the antenna parameters and specify the suitable antenna in BCWCs at both 2.45 GHz and UWB frequencies. Extensive experimental investigations are carried out to study the effects of various antenna types on the on-body radio propagation channels as well. Results and analysis emphasize the best body-worn antenna for reliable and power-efficient on-body communications. Based on the results and analysis, a novel dual-band and dual-mode antenna is proposed for power-efficient and reliable on-body and off-body communications. The on-body performance of the DBDM antenna at 2.45 GHz is compared with other five narrowband antennas. Based on the results and analysis of six narrowband and four UWB antennas, antenna specifications and design guidelines are provided that will help in selecting the best body-worn antenna for both narrowband and UWB systems to be applied in body-centric wireless networks (BCWNs). A comparison between IV the narrowband and UWB antenna parameters are also provided. At the end of the thesis, the subject-specificity of the on-body radio propagation channel at 2.45 GHz and 3-10 GHz was experimentally investigated by considering eight real human test subjects of different shapes, heights and sizes. The subject-specificity of the on-body radio propagation channels was compared between the narrowband and UWB systems as well.

This thesis presents work on antennas and propagation for WBANs at 60 GHz. First, a compact, wearable Vivaldi antenna and Vivaldi antenna array covering the whole unlicensed band from 57 to 64 GHz are proposed to overcome the shadowing due to human movements. Second, multi-hop channels for on-body communication at 60 GHz are investigated through applying the proposed antennas, and it is found that multi-hop wireless network adaption can increase reliability when the separation between sensors exceeds 40 cm compared to single-hop. Radiation pattern diversity is selected among different diversity techniques for providing stable links for 60 GHz WBANs. Results show that radiation pattern diversity enlarges the signal coverage area on the human body, which compensates for the narrow beamwidth antenna, thus more stable links can be established. Finally, a representative channel model for 60 GHz on-body network with an appropriate power control method is presented. With this model and power control method, it has been proved in this thesis that a multi-hop method for on-body communication at 60 GHz is feasible to establish a stable network for different applications.

Doctor of Philosophy<br>Department of Electrical and Computer Engineering<br>William B. Kuhn<br>Balasubramaniam Natarajan<br>Wireless body area networks (WBANs) are an important part of the developing internet of things (IOT). NASA currently uses space suits with wired sensors to collect limited biomedical data. Continuous monitoring and collecting more extensive body vital signs is important to assess astronaut health. This dissertation investigates wireless biomedical sensor systems that can be easily incorporated into future space suits to enable real time astronaut health monitoring. The focus of the work is on the radio-wave channel and associated antennas. We show that the space suit forms a unique propagation environment where the outer layers of the suit’s thermal micrometeoroid garment are largely radio opaque. This environment can be modeled as a coaxial one in which the body itself plays the role of the coax center conductor while the space suit shielding materials play the role of the outer shield. This model is then validated through simulations and experiments. Selecting the best frequency of operation is a complex mixture of requirements, including frequency allocations, attenuation in propagation, and antenna size. We investigate the propagation characteristics for various frequency bands from 315 MHz to 5.2 GHz. Signal attenuation is analyzed as a function of frequency for various communication pathways through 3D simulations and laboratory experiments. Small-scale radio channel results indicate that using lower frequency results in minimal path loss. On the other hand, measurements conducted on a full-scale model suggest that 433 MHz and 2400 MHz yield acceptable path loss values. Propagation between the left wrist and left ankle yielded the worst overall path loss, but signals were still above –100 dBm in raw measurements for a 0dBm transmission indicating that the intra-suit environment is conducive to wireless propagation. Our findings suggest that the UHF bands are best candidate bands since there is interplay between the body conductivity favoring lower frequencies, and the difficulty of coupling RF energy into and out of the channel using suitably sized antennas favoring higher frequencies. Finally, a new self-shielded folded bow-tie antenna is proposed that can be a promising choice for the general area of WBAN technologies as well as potential new space suit environments.

Rowing is an intensive, all-body sport, where bad technique can lead to injury. Crew cohesion, particularly timing, is vital to the performance of the boat. The coaching process, and injury prevention, could be enhanced if data relating to the movement of the oarsmen could be collected, without hindrance to the oarsmen, during on-water training. Literature until recently has concentrated upon boat-centric measurement. Advances in wireless technology have made feasible the collection of data from multiple physically separate sites, including on-body. After analysis of candidate radio standards, a Zigbee wireless Body Sensor Network (BSN) was designed and developed to synchronously collect data from several sensors across the wireless BSN. By synchronising sensor nodes via scheduled synchronising messages from the central coordinating node, synchronisation within 0.79msec ±0.39ms was achieved. Minimisation of the on-time of the sensor node radios currently extends the battery life by a factor of 5. Acceleration and muscle activity data collected using the wireless BSN was compared to data synchronously collected using proven motion analysis techniques to validate the system. Synchronous muscle activity data was collected via the wireless BSN from several muscles during both land-based and on-water rowing and the results compared. The system was proven to facilitate the identification of bad rowing technique, as well as differences in muscle recruitment between land- and water-based rowing. Data collection from a rowing crew was also demonstrated, and their muscle activity and inter-crew timing analysed. With an additional sensor node upon the boat, it is possible to correlate acceleration and muscle activity from the oarsman with acceleration of the boat itself. A novel, power-optimised wireless sensor network has been designed and demonstrated to facilitate on-water rowing monitoring that can be extended beyond single oarsman measurements to analyse the interaction and cohesion of a crew and their impact upon boat performance.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 99-103).<br>Body Area Networks (BANs) are gaining prominence for their use in medical and sports monitoring. This thesis develops the specifications of a ultra-low power 2.4GHz transmitter for use in a Body Area Networks, taking advantage of the asymmetric energy constraints on the sensor node and the basestation. The specifications include low transmit output powers, around -10dBm, low startup time, simple modulation schemes of OOK, FSK and BPSK and high datarates of 1Mbps. An architecture that is suited for the unique requirements of transmitters in these BANs is developed. RF Resonators, and in particular Film Bulk Acoustic Wave Resonators (FBARs) are explored as carrier frequency generators since they provide stable frequencies without the need for PLLs. The frequency of oscillation is directly modulated to generate FSK. Since these oscillators have low tuning range, the architecture uses multiple resonators to define the center frequencies of the multiple channels. A scalable scheme that uses a resonant buffer is developed to multiplex the oscillators' outputs to the Power Amplifier (PA). The buffer is also capable of generating BPSK signals. Finally a PA optimized for efficiently delivering the low output powers required in BANs is developed. A tunable matching network in the PA also enables pulse-shaping for spectrally efficient modulation. A prototype transmitter supporting 3 FBAR-oscillator channels in the 2.4GHz ISM band was designed in a 65nm CMOS process. It operates from a 0.7V supply for the RF portion and 1V for the digital section. The transmitter achieves 1Mbps FSK, up to 10Mbps for OOK and BPSK without pulse shaping and 1Mbps for OOK and BPSK with pulse shaping. The power amplifier has an efficiency of up to 43% and outputs between -15dBm and -7.5dBm onto a 50Q antenna. Overall, the transmitter achieves an efficiency of upto 26% and energy per bit of 483pJ/bit at 1Mbps.<br>by Arun Paidimarri.<br>S.M.

The main contribution of the thesis is to provide modeling, analysis, and design for Medium Access Control (MAC) and link-quality based routing protocols of Wireless Body Area Sensor Networks (WBASNs) for remote patient monitoring applications by considering saturated and un-saturated traffic scenarios. The design of these protocols has considered the stringent Quality of Service (QoS) requirements of patient monitoring systems. Moreover, the thesis also provides intelligent routing metrics for packet forwarding mechanisms while considering the integration of WBASNs with the Internet of Things (IoTs). First, we present the numerical modeling of the slotted Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) for the IEEE 802.15.4 and IEEE 802.15.6 standards. By using this modelling, we proposed a MAC layer mechanism called Delay, Reliability and Throughput (DRT) profile for the IEEE 802.15.4 and IEEE 802.15.6, which jointly optimize the QoS in terms of limited delay, reliability, efficient channel access and throughput by considering the requirements of patient monitoring system under different frequency bands including 420 MHz, 868 MHz and 2.4 GHz. Second, we proposed a duty-cycle based energy efficient adaptive MAC layer mechanism called Tele-Medicine Protocol (TMP) by considering the limited delay and reliability for patient monitoring systems. The proposed energy efficient protocol is designed by combining two optimizations methods: MAC layer parameter tuning and duty cycle-based optimization. The duty cycle is adjusted by using three factors: offered network traffic load, DRT profile and superframe duration. Third, a frame aggregation scheme called Aggregated-MAC Protocol Data Unit (A- MPDU) is proposed for the IEEE 802.15.4. A-MPDU provides high throughput and efficient channel access mechanism for periodic data transmission by considering the specified QoS requirements of the critical patient monitoring systems. To implement the scheme accurately, we developed a traffic pattern analysis to understand the requirements of the sensor nodes in patient monitoring systems. Later, we mapped the requirements on the existing MAC to find the performance gap. Fourth, empirical reliability assessment is done to validate the wireless channel characteristics of the low-power radios for successful deployment of WBASNs/IoTs based link quality routing protocols. A Test-bed is designed to perform the empirical experiments for the identification of the actual link quality estimation for different hospital environments. For evaluation of the test-bed, we considered parameters including Received Signal Strength Indicator (RSSI), Link Quality Indicator (LQI), packet reception and packet error rate. Finally, there is no standard under Internet Engineering Task Force (IETF) which provides the integration of the IEEE 802.15.6 with IPv6 networks so that WBASNs could become part of IoTs. For this, an IETF draft is proposed which highlights the problem statement and solution for this integration. The discussion is provided in Appendix B.

Mestrado em Engenharia de Computadores e Telemática<br>Internet of Things (IoT) is a generic category of ICT architectures that includes the use of sensor-based, communication-enabled systems. A common architectural element in IoT is the sensors gateway that collects data from nearby sensors and relays them to higher-order remote services. The VR2Market project, in which this work is integrated, uses two implementations of the gateway, based on Android smartphones and RPI boards. With the new proposed IoT-inspired computing module, it is possible to migrate gateways to a smaller, more efficient hardware, while retaining the high-level programming abstraction. In this work, we propose and implement a new version of the gateway, named VR-Banway, using the Intel Edison compute module, taking into consideration the integration with additional service layers in VR2Market system, especially with respect to the required Ad hoc networks support. VR-Banway proved to be a solution capable of replacing the existing gateway component in the VR2Market system. The new approach uses a smaller module, reduces power consumption and is more portable. VR-Banway has been used in the context of firefighters monitoring, but is ready to be deployed in other domains.<br>A Internet of Things (IoT) é uma categoria genérica das arquiteturas de TIC que inclui o uso de sistemas baseados em sensores e comunicações. Um elemento comum das arquiteturas IoT é o agregador que recolhe dados de sensores nas proximidades e reencaminha-os para serviços remotos de mais alto nível. O projeto VR2Market, no qual este trabalho está integrado, usa duas implementações do agregador de dados, implementados em Android e RPI. Com o novo módulo proposto, inspirado na IoT, é possível migrar os agregadores de dados para dispositivos mais pequenos e mais eficientes mantendo a abstração de programação de alto nível. Neste trabalho, propomos e implementamos uma nova versão do agregador de dados, chamado VR-Banway, usando o módulo computacional Intel Edison, tendo em consideração a integração de novas camadas de serviços no VR2Market, especialmente no que diz respeito ao suporte de redes Ad hoc. VR-Banway provou ser uma solução capaz de substituir o componente de agregador de dados existente no sistema VR2Market. A nova abordagem usa um módulo mais pequeno, reduz o consumo de energia e é mais portátil. VR-Banway foi usado no contexto de monitorização de bombeiros, mas está preparado para ser implementado noutros domínios.