The IEEE 802.15.4 standard is an interesting technology for use in Wireless Body Sensor Networks (WBSN), where entire networks of sensors are carried by humans. In many environments the sensor nodes experience external interference for example, when the WBSN is operated in the 2.4 GHz ISM band and the human moves in a densely populated city, it will likely experience WiFi interference, with a quickly changing ``interference landscape''. In this thesis we propose Adaptive Resource Allocation schemes, to be carried out by the WBSN, which provided noticeable performance gains in such environments. We investigate a range of adaptation schemes and assess their performance both through simulations and experimentally.

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The presented work considers a CDMA-based Wireless Body Area Network (WBAN) where multiple biosensors communicate simultaneously to a central node in an asynchronous fashion. The asynchronous nature of the WBAN introduces Multiple Access Interference (MAI). To combat this problem, presented is a methodology that uses a set of cyclically orthogonal spreading codes extracted from the Walsh-Hadamard matrix. When using the Cyclic Orthogonal Walsh-Hadamard Codes (COWHC) as spreading codes in the CDMA-based WBAN, the cyclic orthogonality property helps mitigate MAI amongst the on-body sensors. Presented is an ideal communication system that is most effective at mitigating MAI in proactive WBANs. The work illustrates the system optimality and effectiveness at mitigating MAI by studying the sensitivity to packet-loss through simulating the link Bit Error Rate (BER) performance. It is shown that the proposed design with COWHC, a Rayleigh flat-fading channel, BPSK modulation and a conventional receiver produce optimum MAI mitigation.

The presented work considers a CDMA-based Wireless Body Area Network (WBAN) where multiple biosensors communicate simultaneously to a central node in an asynchronous fashion. The asynchronous nature of the WBAN introduces Multiple Access Interference (MAI). To combat this problem, presented is a methodology that uses a set of cyclically orthogonal spreading codes extracted from the Walsh-Hadamard matrix. When using the Cyclic Orthogonal Walsh-Hadamard Codes (COWHC) as spreading codes in the CDMA-based WBAN, the cyclic orthogonality property helps mitigate MAI amongst the on-body sensors. Presented is an ideal communication system that is most effective at mitigating MAI in proactive WBANs. The work illustrates the system optimality and effectiveness at mitigating MAI by studying the sensitivity to packet-loss through simulating the link Bit Error Rate (BER) performance. It is shown that the proposed design with COWHC, a Rayleigh flat-fading channel, BPSK modulation and a conventional receiver produce optimum MAI mitigation.

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-12-03T17:40:18Z No. of bitstreams: 2 Dissertação - Roberto Vito Rodrigues Filho - 2013.pdf: 5032081 bytes, checksum: 38e74b2094416a7b86dc95fcf2ace961 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-12-04T14:50:02Z (GMT) No. of bitstreams: 2 Dissertação - Roberto Vito Rodrigues Filho - 2013.pdf: 5032081 bytes, checksum: 38e74b2094416a7b86dc95fcf2ace961 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-12-04T14:50:02Z (GMT). No. of bitstreams: 2 Dissertação - Roberto Vito Rodrigues Filho - 2013.pdf: 5032081 bytes, checksum: 38e74b2094416a7b86dc95fcf2ace961 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-08-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Body Sensor Networks (BSN) are a technology used to supply individual’s vital signs to ubiquitous and pervasive systems. This systems applied to the healthcare area uses BSN to monitor patient’s vital signs remotely, that is without them being in a hospital environment. This technology applied as a base to this application assists healthcare professional to remotely monitor patients, which contribute to solve healthcare services problems. One of those problems is the crowded treatments centers. The usage of BSN, by conditioning remote monitoring, can colaborate to reduce the patients’ needs to consistently go to hospitals, thus contributing to reduce the number of patients in those environments. Given this tecnology potential comes the need to develop good quality applications. However, considering an analysis of BSN projects applied to the healthcare field, the usage of inadequated hardware platforms are noticed. Therefore aiming to make the development of this type of applications easier, it is proposed a simulator specific for BSN applied to the healthcare field. Hence, this work’s goal is to show this application simulator through the usage of a simulated hardware platform which takes intoconsiderationhealthcare demands to provide a test environment. / As Redes de Sensores do Corpo Humano (RSCH) são uma tecnologia utilizada para o fornecimento de sinais vitais de um indivíduo para sistemas pervasivos. Esses sistemas aplicados à área da saúde utilizam as RSCH para o monitoramento de sinais vitais de um paciente de forma remota, sem que o mesmo tenha que estar em um ambiente hospitalar. Essa tecnologia usada como base dessas aplicações, auxiliam os profissionais da saúde no monitoramento de pacientes à distância, ajudando a resolver problemas na prestação de serviço de saúde. Um desses problemas é a lotação dos centros de atendimento. A utilização das RSCH, por condicionar o monitoramento remoto, colabora na redução da necessidadeconstantedaidadopacienteaoshospitais,contribuindoassimcomaredução da lotação nesses ambientes. Com o potencial dessa tecnologia surge a necessidade de desenvolver aplicações de qualidade. Entretanto, considerando uma análise dos projetos de RSCH aplicados à área da saúde, nota-se a realização de testes em ambientes e plataformas de hardware inadequados. Dessa forma, visando facilitar o desenvolvimento deaplicaçõesnestaárea,épropostoumsimuladorespecíficoparaRSCHaplicadasàárea dasaúde.Assim,oobjetivodestetrabalhoémostraressesimuladordeaplicaçõesatravés da utilização de uma plataforma simulada de hardware, a qual leva em consideração as demandas da área médica, para prover um ambiente de testes.

Wireless personal area networks have emerged as an important communication infrastructure in areas such as at-home healthcare and home automation, independent living and assistive technology, as well as sports and wellness. Wireless personal area networks, including body sensor networks, are becoming more mature and are considered to be a realistic alternative as communication infrastructure for demanding services. However, to transmit data from e.g., an ECG in wireless networks is also a challenge, especially if multiple sensors compete for access. Contention-based networks offer simplicity and utilization advantages, but the drawback is lack of predictable performance. Recipients of data sent in wireless sensor networks need to know whether they can trust the information or not. Performance measurements, monitoring and control is of crucial importance for medical and healthcare applications in wireless sensor networks. This thesis focuses on development, prototype implementation and evaluation of a performance management system with performance and admission control for wireless sensor networks. Furthermore, an implementation of a new method to compensate for clock drift between multiple wireless sensor nodes is also shown. Errors in time synchronization between nodes in Bluetooth networks, resulting in inadequate data fusion, are also analysed. / <p>QC 20120529</p>

Body sensor networking is a rapidly growing technology. Today wearable sensors are used to measure and monitor e.g. pulse, temperature, skin conductance, heart activity, and movement (through GPS or inertial measurement units). Mobile phones can act as coordinating nodes in wireless personal area networks used in home automation, healthcare, sport and wellness e.g. to measure pulse and distance. Integration of data from multiple sources sensors (data fusion) means that data from each sensor node needs to be associated with data from other sensor nodes sampled at approximately the same time. Accurate methods for time synchronization are therefore a necessary prerequisite for reliable data fusion. This thesis studies time synchronization problems in Bluetooth piconets between multiple wireless sensor nodes connected to a mobile phone that acts as coordinating node. Three different algorithms to enable correct data fusion have been developed, implemented and evaluated. The first is a single clock solution that synchronizes multiple wireless sensor nodes based solely on the mobile phone’s clock. The other two algorithms synchronize the clocks in sensor nodes to the clock in the coordinating node. / <p>QC 20130605</p>