Channel Impairments
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Assessment of Total Attenuation and Adaptive Scheme for Quality of Service Enhancement in Tropical Weather for Satellite Networks and 5G Applications in Nigeria
Abstract The dynamic weather condition is a major concern for optimum channel utilization in recent times, especially at higher frequencies with larger bandwidth for 5G applications. Over the years, rain-induced attenuation among the hydrometeors has been linked as the major cause of signal impairment especially at the frequency, f ≥ 10 GHz. However, when
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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2. Link Optimization and Performance Analysis of a 40 Gbps DQPSK Modulated Ultra DWDM System with 32 Orthogonally Polarized channels
Abstract The demand for higher speed at a lesser transmission cost per bit resulted in growth of optical networks with improved spectral efficiency even at narrower channel spacing. Incorporation of multilevel modulation formats in DWDM system led to the exploration of the 25 GHz channel grid, popularly known as Ultra Dense Wavelength Division Multiplexed (U
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-12
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3. Phase Noise Effects on Wideband Mobile Radio Channel Sounding
Abstract In this work three wideband mobile radio channel sounding methods are simulated and compared using computational tools. The considered sounders include the traditional STDCC and two other proposed sounding methods that are based on OFDM digital transmission and detection procedures and on matched filtering. The impact of the phase noise introduced b
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-12
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4. Algoritmos RWA para redes ópticas transparentes considerando limitações da camada física / RWA algorithms for optical transparent networks considering physical impairments
With the proliferation of new multimedia services such as VoIP and IP-TV, an increasing demand for high rates of data transfer is being seen. Thus, the demand on the core of the network is continuously growing, so its capacity must increase in the same ratio to provide a reliable service to end users. The Transparent Optical Networks with WDM appears as a so
Publicado em: 2010
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5. m estudo sobre o uso da codificação de canal para otimização do consumo de energia em redes de sensores
Wireless Sensor Networks (WSN) are a set of tiny electronic devices, which monitor physical phenomena over a specific region and send this data to a sink node. The sensor nodes connect to the other ones in the range of the transmitted signal, establishing a collaborative network operation. The collected data are forwarded to other nodes until the sink is rea
Publicado em: 2007
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6. Caracterização e análise de desempenho dos amplificadores ópticos Raman discretos em sistemas de comunicações ópticas na banda O
The optical amplifier has improved the optical communication systems because they lead to an increase in transmission capacity of medium and long haul optical systems, with technological advantages over electronic regenerators. The optical amplifier are relatively simple to deploy and can be used in optical links without any troubles regarding signal transmi
Publicado em: 2006
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7. Tecnicas autodidatas e soluções de baixa complexidade para equalização e estimação turbo
This work concerns the use of iterative receivers, which jointly perform equalization, decoding and channel estimation, to mitigate the impairments introduced by the transmission medium into the transmitted signal. First, we make a comparative study of exponential-and reduced-complexity turbo equalizers and establish the advantages and the limitations of eac
Publicado em: 2005
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8. Processamento adaptativo para cancelamento da interferencia de polarização cruzada em sistemas radio digitais
A interesting approach to improve the spectral efficiency of a digital radio system is the utilization the frequency reuse technique. However due to of the propagation impairments, there exist mutual interference between these two orthogonal channels, known as cross polarization interference. This work studies the interference cancellation by means of adapti
Publicado em: 1991
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9. EFECT OF LINEAR DISTORTION IN DIGITAL TRANSMISSSION SYSTEMS / EFEITO DE DISTORÇÕES LINEARES EM SISTEMAS DE TRANSMISSÃO DIGITAL
O trabalho analisa o desempenho de sistemas de transmissão digital com modulação de amplitude em quadratura (QAM), considerando o efeito de distorções na função de transferência do canal de transmissão. Assumindo formas polinomiais, senoidais e exponenciais para a função de transferência do canal, são calculados analiticamente o valor médio qua
Publicado em: 1991
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10. Congenital sick sinus syndrome caused by recessive mutations in the cardiac sodium channel gene (SCN5A)
Sick sinus syndrome (SSS) describes an arrhythmia phenotype attributed to sinus node dysfunction and diagnosed by electrocardiographic demonstration of sinus bradycardia or sinus arrest. Although frequently associated with underlying heart disease and seen most often in the elderly, SSS may occur in the fetus, infant, and child without apparent cause. In thi
American Society for Clinical Investigation.
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11. Noninactivating voltage-gated sodium channels in severe myoclonic epilepsy of infancy
Mutations in SCN1A, the gene encoding the brain voltage-gated sodium channel α1 subunit (NaV1.1), are associated with at least two forms of epilepsy, generalized epilepsy with febrile seizures plus and severe myoclonic epilepsy of infancy (SMEI). We examined the functional properties of five SMEI mutations by using whole-cell patch-clamp analysis of heterol
National Academy of Sciences.
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12. Differential abscisic acid regulation of guard cell slow anion channels in Arabidopsis wild-type and abi1 and abi2 mutants.
Abscisic acid (ABA) regulates vital physiological responses, and a number of events in the ABA signaling cascade remain to be identified. To allow quantitative analysis of genetic signaling mutants, patch-clamp experiments were developed and performed with the previously inaccessible Arabidopsis guard cells from the wild type and ABA-insensitive (abi) mutant