Ofdm
Mostrando 1-12 de 61 artigos, teses e dissertações.
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1. Efficient Low-Complexity Optimized Channel Estimating Methods for OFDM-Based Low-Voltage Broadband Power Line Communication Systems
Abstract Broadband Power Line Communication (BB-PLC) technology enables data transmission for smart grid applications. Nevertheless, channel equalizers are required in the receiver to estimate and compensate for the nonlinear time-variant impulse response and noise interference effects introduced by the BB-PLC channel. In this paper, we append the Particle S
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Low-Overhead Low-Complexity Carrier Phase Recovery Technique for Coherent Multi-Band OFDM-Based Superchannel Systems Enabled by Optical Frequency Combs
Abstract In this paper, we have designed a low-overhead low-complexity carrier phase tracking scheme for OFDM-based superchannel transmission system enabled by optical frequency combs. In this scheme, taking advantage of the broadband phase coherence provided by optical frequency combs among the OFDM-bands, the carrier phase retrieved from pilot-subcarriers
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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3. Spatial Diversity Effect on the Experimental Gain of Capacity of the Outdoor Mobile Radio Channel in the 700 MHz Band
Abstract From measurements performed in the 700 MHz band, this paper analyzes the effect of spatial diversity on the channel capacity through the propagation of an OFDM mobile radio signal and compares with the results of a single branch providing what improvement of the capacity is attained with the SIMO system.
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-06
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4. 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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5. A Low Complexity Iterative SLM-OFDM for SHF band applications
Abstract The transmitted Orthogonal Frequency Division Multiplexing signal in systems such as Wireless LAN, Mobile WiMAX, Digital Video Broadcasting (DVB) operating in the Super High Frequency (SHF) band suffers from high Peak to Average Power Ratio. This is reduced in Selective Level Mapping (SLM)approach but at the expense of increased complexity. In this
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-09
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6. Heuristics for the optimized deployment of small cells in next-generation networks
Abstract Heterogeneous Networks (HetNets) have been introduced as an alternative means of improving the overall network capacity. However, HetNets increase the complexity and cost of transport due to the large number of smallcells (SCs) that have to be connected, and hence, it is essential to investigate the best way to plan the joint deployment of radio and
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-09
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7. Experimental Evaluation of the Mobile Radio Channel Capacity in the 2.48 GHz Band
Abstract This paper deals with the effect of the Single-Input Multiple-Output spatial diversity on the OFDM mobile radio signal propagating in an urban channel. From measurements performed in Rio de Janeiro city, Brazil, by using two receiving antennas at diversity, the calculated capacity presented an improvement when compared to the individual one.
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
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8. Estimação de Probabilidade de Transbordo do Buffer em Redes OFDM-TDMA utilizando Cadeias de Markov e Curva de Serviço
RESUMO Este trabalho apresenta duas abordagens para estimação de probabilidade de transbordo do buffer em redes OFDM-TDMA. A primeira abordagem, se baseia em Cadeias de Markov e em Teoria de Filas para descrever o desempenho do enlace de transmissão em sistemas OFDM-TDMA. A segunda abordagem se baseia em curva de serviço e no conceito de Processo Envelop
TEMA (São Carlos). Publicado em: 2016-04
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9. 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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10. A Compact Dual-Band Octagonal Slotted Printed Monopole Antenna for WLAN/ WiMAX and UWB Applications
AbstractA compact (20 x 20 mm2 size), coplanar waveguide (CPW) fed, octagonal slotted, dual-band antenna is presented in this paper. The proposed antenna has a simple structure consisting of an octagonal slot, L-shape stub, and a two stepped rectangular patch. The introduction of the L-shaped metallic stubs in the ground plane generates a lower resonance fre
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-06
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11. Comparison between OFDM and STDCC mobile channel sounders at 3.5 GHz
In this paper, we present a comparison between OFDM and STDCC sounding techniques used to wide band channel characterization in suburban environments at 3.5 GHz band. Measurements of the received signal's power delay profile and power level for each of the sounding techniques were obtained. These experimental results are presented and compared. For this comp
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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12. Estudos de sistemas OFDM para comunicações ópticas / Studies OFDM systems for optical communications
The development of digital modulation formats in optical communications systems is considered to be a promising way to increase the spectral efficiency and to combat the effects of signal degradation in optical fiber without changing the infrastructure already deployed. In this context, the technique called OFDM (orthogonal frequency division multiplexing) e
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/10/2012