<p>Wireless Sensor Network is an emerging technology that has applicationsin Wireless Actuators, remote controlling, distribution of softwareupdates and distribution of parameters to sensor nodes. This projectwork basically covers the concept of macro-diversity. This is a situationin which several transmitters are used for transferring the same signal (inmulti-hop sensor networks) to check the increase in connected nodes orin network coverage. Transmitter macro-diversity increases the receivedsignal strength and thus increases the signal-to-noise ratio which resultsin a lower outage probability. To accomplish this task three differentstrategies have been simulated using thirteen different cases. Broadcastingis used when forming SFN of size one (strategy one) and uni-castingis used for forming SFNs of size two (strategy two) and size three (strategythree).In this project reference material has been gathered frombooks, journals and web sources; and MATLAB has been used as thesimulation tool in which codes are written in the M programming language.The algorithm works firstly by discovering all the nodes that areconnected directly with the Base Station through multi-hoping, afterwhich the second algorithm is applied to check how many more nodescan be reached by forming SFNs. A gain of up to 79% was observedusing strategy one and strategy two and up to 83% in strategy three.The results shows that strategy one (Forming SFNs using BroadcastingTechnique) is the best as more nodes can be reached (for different cases)than for the other two strategies (forming SFNs using uni-casting technique).</p>

Wireless Sensor Network is an emerging technology that has applicationsin Wireless Actuators, remote controlling, distribution of softwareupdates and distribution of parameters to sensor nodes. This projectwork basically covers the concept of macro-diversity. This is a situationin which several transmitters are used for transferring the same signal (inmulti-hop sensor networks) to check the increase in connected nodes orin network coverage. Transmitter macro-diversity increases the receivedsignal strength and thus increases the signal-to-noise ratio which resultsin a lower outage probability. To accomplish this task three differentstrategies have been simulated using thirteen different cases. Broadcastingis used when forming SFN of size one (strategy one) and uni-castingis used for forming SFNs of size two (strategy two) and size three (strategythree).In this project reference material has been gathered frombooks, journals and web sources; and MATLAB has been used as thesimulation tool in which codes are written in the M programming language.The algorithm works firstly by discovering all the nodes that areconnected directly with the Base Station through multi-hoping, afterwhich the second algorithm is applied to check how many more nodescan be reached by forming SFNs. A gain of up to 79% was observedusing strategy one and strategy two and up to 83% in strategy three.The results shows that strategy one (Forming SFNs using BroadcastingTechnique) is the best as more nodes can be reached (for different cases)than for the other two strategies (forming SFNs using uni-casting technique).

Orientador: Yuzo Iano / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-08T10:21:08Z (GMT). No. of bitstreams: 1 Arthur_Rangel_D.pdf: 3675976 bytes, checksum: 65350df75e5a9588b1366325ac95ef62 (MD5) Previous issue date: 2007 / Resumo: Esta tese trata da otimização de receptores de TV Digital baseados em OFDM, com avaliação de desempenho em redes de retransmissão em freqüência única (SFN . Single Frequency Networks) regionais. Tal ambiente facilita a distribuição de canais, porém possui características que dificultam o trabalho do receptor. São tratados, inicialmente, de projetos de filtros canceladores de elos de realimentação em estações retransmissoras, que ocorrem quando a antena de transmissão interfere na antena de recepção. Um novo filtro, baseado em técnicas que utilizam informação temporal é proposto. Novas propostas são feitas para as partes de sincronismo, estimação e equalização de canal, e codificação/decodificação. Uma técnica, vinda da teoria de reconhecimento de padrões, é aplicada para diminuição da complexidade no processo de sincronismo temporal. Um sistema de estimação de canal 2D e equalização adaptativa, usando o LMS (Least Mean Square), é comparado com técnicas clássicas da literatura, e um ganho significativo é encontrado. Como novo esquema de codificação e decodificação é proposto um esquema iterativo, baseado em códigos turbo, com número reduzido de iterações. Tal código melhora o desempenho do sistema em relação ao uso combinado dos decodificadores Viterbi e Reed Solomon. Todas as propostas são combinadas para se avaliar o desempenho do receptor diante de condições típicas de SFN e multicaminhos típicos em recepção de TV do Brasil / Abstract: This thesis deals with the optimization of Digital TV receivers based on OFDM, with performance evaluation in regional single frequency networks (SFN). Such environment facilitates the channel distribution, however its characteristics degrade the receiver operation. Initially, projects of loop canceller filters in relay stations are treated, and they are necessary when the transmission antenna causes interference on reception antenna. A new filter, based on time information is proposed. New proposals are made for the synchronism, channel estimation and equalization, and coding/decoding. One technique, coming from the pattern recognition theory, is applied for complexity reduction in the process of time synchronism. A 2D channel estimation system and adaptive equalization, using LMS (Least Mean Square), is compared to classical techniques in the literature, and a significant gain is achieved. As a new coding and decoding scheme, an iterative system based on turbo codes is used with reduced number of iterations. Such code improves the system performance when compared to the Viterbi and Reed Solomon concatenated decoders. The proposals are combined and the performance of the proposed receiver is evaluated on typical conditions of SFN and on typical multipaths for TV reception in Brazil / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica