Multicarrier Modulation
Mostrando 1-7 de 7 artigos, teses e dissertações.
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1. Evaluation of OFDM Channel Sounding Techniques with Three Modulation Sequences
Abstract This paper presents an evaluation of multicarrier channel sounding techniques using different random and pseudo-random sequences to modulate the OFDM sounding signal. The Random (Rand), Pseudo-Noise (PN) and Zadoff-Chu (ZC) were tested, both in laboratory simulations and in field measurements. For the laboratory simulations Matlab routines were used
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 11/11/2019
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2. MI-SBTVD: a proposal for the Brazilian digital television system SBTVD
The objective of this paper is to present a general overview of the Innovative Modulation System Project -MI-SBTVD - developed for the Brazilian Digital TV System. The MI-SBTVD Project includes an LDPC high performance error correcting code, an advanced transmit spatial diversity and an efficient multi-carrier modulation scheme. The building blocks of the sy
Journal of the Brazilian Computer Society. Publicado em: 2007-03
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3. Frequency domain concurrent channel equalization for multicarrier systems
Receivers for wireless Orthogonal Frequency Division Multiplexing (OFDM) systems usually perform the channel estimation based on pilot carriers in known positions of the channel spectrum. Interpolation between pilot carriers is applied to determine the channel transfer function in all carrier frequencies. Channel variations along time are compensated by mean
Journal of the Brazilian Computer Society. Publicado em: 2007-03
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4. EQUALIZAÇÃO E ESTIMAÇÃO DE CANAL EM SISTEMAS DE TRANSMISSÃO OFDM / EQUALIZATION AND CHANNEL ESTIMATION IN OFDM TRANSMISSION SYSTEMS
crescimento dos sistemas de comunicações móveis celulares e dos sistemas de rádio difusão de sinais de áudio e vídeo tem despertado grande interesse na pesquisa de novos métodos para a transmissão de sinais nestas redes. A necessidade de se transmitir dados em altas taxas, com significante eficiência no uso da largura de faixa de freqüências disp
Publicado em: 2005
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5. Modulação Multiportadora M-QAM Não-Quadrada Codificada por Blocos para Canais com Modelo de Rummler
Um dos principais fatores que provocam a degradação da qualidade dos sistemas digitais de longo alcance em linha de visada com taxas de transmissão na ordem de algumas dezenas de Mb/s, são os desvanecimentos seletivos em freqüência. Uma das alternativas para diminuir o efeito provocado pelos desvanecimentos seletivos em freqüência é a utilização d
Publicado em: 2004
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6. Performance Analisys of Multicarrier Systems in Peak Clipping Channels / Análise de Desempenho de Sistemas Multiportadora em Canais com Ceifamento de Pico
The advent of Digital Television brought a new scenario to the digital telecommunication systems, presenting new problems and challenges to be efficiently solved. Today, there are three different standards for Digital Television available: the ATSC developed in USA, DVB-T developed in Europe and ISDB-T developed in Japan. Two of these standards use a transmi
Publicado em: 2003
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7. Modulação multiportadora codificada por bloco para radioenlaces digitais em microondas com linha de visada
The availability of line-of-sight (LOS) microwave digital systems which work at high transmission rates such as 155 Mb/s, may be strongly limited by frequency-selective fading effects. The main countermeasure techniques against the fading are equalizations, diversity and error control coding. Under adverse geoclimatic conditions, the path length and/or the t
Publicado em: 2002