The Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard presents a very useful technology for implementing low-cost, low-power, wireless sensor networks. Its main focus, which is to applications requiring simple wireless connectivity with relaxed throughout and latency requirements, makes it suitable for connecting devices that have not been networked, such as industrial and control instrumentation equipments, agricultural equipments, vehicular equipments, and home appliances. Its usage of the license-free 2.4 GHz frequency band makes the technique successful for fast and worldwide market deployments. However, concerns about interference have arisen due to the presence of other wireless technologies using the same spectrum. Although the IEEE 802.15.4 standard has provided some mechanisms, to enhance capability to coexist with other wireless devices operating on the same frequency band, including Carrier Sensor Multiple Access (CSMA), Clear Channel Assessment (CCA), channel alignment, and low duty cycle, it is essential to design and implement adjustable mechanisms for an IEEE 802.15.4 based system integrated into a practical application to deal with interference which changes randomly over time. Among the potential interfering systems (Wi-Fi, Bluetooth, cordless phones, microwave ovens, wireless headsets, etc) which work on the same Industrial, Scientific, and Medical (ISM) frequency band, Wi-Fi systems (IEEE 802.11 technique) have attracted most concerns because of their high transmission power and large deployment in both residential and office environments. This thesis aims to propose a methodology for IEEE 802.15.4 wireless systems to adopt proper adjustment in order to mitigate the effect of interference caused by IEEE 802.11 systems through energy detection, channel agility and data recovery. The contribution of this thesis consists of five parts. Firstly, a strategy is proposed to enable IEEE 802.15.4 systems to maintain normal communications using the means of consecutive transmissions, when the system s default mechanism of retransmission is insufficient to ensure successful rate due to the occurrence of Wi-Fi interference. Secondly, a novel strategy is proposed to use a feasible way for IEEE 802.15.4 systems to estimate the interference pattern, and accordingly adjust system parameters for the purpose of achieving optimized communication effectiveness during time of interference without relying on hardware changes and IEEE 802.15.4 protocol modifications. Thirdly, a data recovery mechanism is proposed for transport control to be applied for recovering lost data by associating with the proposed strategies to ensure the data integrity when IEEE 802.15.4 systems are suffering from interference. Fourthly, a practical case is studied to discuss how to design a sustainable system for home automation application constructed on the basis of IEEE 802.15.4 technique. Finally, a comprehensive design is proposed to enable the implementation of an interference mitigation strategy for IEEE 802.15.4 based ad hoc WSNs within a structure of building fire safety monitoring system. The proposed strategies and system designs are demonstrated mainly through theoretical analysis and experimental tests. The results obtained from the experimental tests have verified that the interference caused by an IEEE 802.11 system on an IEEE 802.15.4 system can be effectively mitigated through adjusting IEEE 802.15.4 system s parameters cooperating with interference pattern estimation. The proposed methods are suitable to be integrated into a system-level solution for an IEEE 802.15.4 system to deal with interference, which is also applicable to those wireless systems facing similar interference issues to enable the development of efficient mitigation strategies.

Orientador: João Mauricio Rosario / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-15T00:29:26Z (GMT). No. of bitstreams: 1 Carvalho_MarcosCorreade_M.pdf: 12573489 bytes, checksum: ef9faf7fa22617d76e44ea3d342a5073 (MD5) Previous issue date: 2009 / Resumo: Automação Predial é uma área da Engenharia que envolve a integração de diferentes conhecimentos, e através do crescimento explosivo da Internet e investimentos em infra-estrutura de comunicações, tem estimulado a incorporação de soluções tecnológicas inovadoras para automação em novos e já existentes empreendimentos, baseadas na busca do conforto, segurança, entretenimento e acessibilidade que se tornam disponíveis a um grande número de usuários. Neste contexto, este trabalho tem como principal objetivo apresentar uma proposta de metodologia para integração de sistemas de automação predial, baseados em conceitos já utilizados para sistemas automatizados industriais, direcionando a área de Automação Predial, a partir da integração dos sistemas independentes e modulares, visando a melhoria da qualidade de vida através da sistematização e planejamento de recursos, otimização de tempos, segurança, racionalização de serviços, qualidade, utilização do espaço, e uso eficiente de energia e recursos naturais. A comprovação experimental deste trabalho será realizada através de três aplicações industriais que mostram vantagens e benefícios dos conceitos apresentados, estruturação do problema, especificação de sensores e atuadores, sistema de supervisão e controle remoto (WeLlab) e integração de soluções em automação predial. / Abstract: Building automation is an engineering area that integrates others such as the ones of electrical, mechanics, electronics and computer science. It is thanks to the internet vast growth and communication infrastructure investments that innovative technical solutions for automation have taken place in the search for guaranteeing user's comfort, security, entertaining and accessibility. From the previous perspective, this work establish as main objective, the presentation of a methodology for systems integration in building automation based on industrial automation concepts applied to the building area. This allows the integration of independent and modular systems for offering an improved life quality thanks to the time, space and security handling and planning through the efficient use of natural and energetic resources. The experimental validation is done through three industrial applications which allow analyzing from the proposed methodology, how the problem structure, sensor and actuator selection, supervisory system and remote control (WebLab) can be integrated within a building automation solution. / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica