Results 181 to 190 of about 14,247 (230)
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IEEE Wireless Communications Letters, 2012
This letter investigates the construction methods of perfect 8-QAM+ sequences, which relate to one of three open problems proposed by Boztas and Parampalli in 2010, and two constructions that transform the known perfect ternary sequences (PTSs) into the required sequences are presented.
Fanxin Zeng +4 more
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This letter investigates the construction methods of perfect 8-QAM+ sequences, which relate to one of three open problems proposed by Boztas and Parampalli in 2010, and two constructions that transform the known perfect ternary sequences (PTSs) into the required sequences are presented.
Fanxin Zeng +4 more
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Demodulation of cochannel QAM signals
International Conference on Acoustics, Speech, and Signal Processing, 2003The authors describe a technique for demodulating a quadrature amplitude modulated (QAM) signal in the presence of a second cochannel QAM interferer and intersymbol interference. The method consists of a two-step procedure whereby tentative estimates of both the desired and interfering signals are made and then converted into final estimates by ...
Richard P. Gooch, Brian J. Sublett
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Energy Minimization of a QAM System
2007 IEEE Wireless Communications and Networking Conference, 2007In this paper, an energy minimization problem for a quadrature amplitude modulation (QAM) system with automatic repeat request (ARQ) is considered. We formulate an optimization problem with constellation size and transmit power as the variables. We give an efficient and accurate geometric programming (GP) approximation to the problem and illustrate the
Raghavendra S. Prabhu +2 more
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Simplified analysis of QAM BER impairment in hybrid AM/QAM lightwave systems
IEEE Transactions on Communications, 1999A new simplified approach for QAM signal error analysis in hybrid AM/QAM lightwave systems is proposed. The method allows fast and accurate BER calculation.
Qi Pan, Roger J. Green
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Information rates for the SP 128-QAM and DP 16-QAM modulation formats
2015 European Conference on Optical Communication (ECOC), 2015Information rates for the set-partitioning (SP) 128-QAM and dual-polarization (DP) 16-QAM modulation formats are compared for the same bit rate (256 Gbit/s) and baud rate (32 Gbaud). For 256 Gbit/s transmission over 3600 km, SP 128-QAM offers an increase of 8.2%.
Aazar S. Kashi +8 more
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QAM for terrestrial and cable transmission
IEEE Transactions on Consumer Electronics, 1995We introduce quadrature amplitude modulation (QAM) and discuss QAM architectures used to overcome transmission impairments typically encountered on 6 MHz wide terrestrial and cable TV VHF/UHF channels. The input data to the QAM transmitter is mapped into N bit words called symbols; N determines the QAM level.
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Construction and Labeling of Triangular QAM
IEEE Communications Letters, 2017We propose two algorithms: one is for building and the other for labeling triangular QAM (TQAM) constellations. A root distribution algorithm (also referred as RD) is used to construct TQAM constellations of low average energy. The proposed labeling algorithm, termed the layer labeling algorithm, results in bit-to-symbol mappings that minimize the ...
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Polarization QAM Modulation (POL-QAM) for Coherent Detection Schemes
Optical Fiber Communication Conference and National Fiber Optic Engineers Conference, 2009A new polarization constellation diagram leads to polarization QAM modulation formats. At 28Gbaud (112Gb/s) POL-QAM 6-4 with six QPSK modulated states-of-polarization enables 1.7-dB higher sensitivity than PDM-QPSK by applying coded-modulation with an inner RS(511,455) FEC.
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Experimental Comparison of 64-QAM and Combined Geometric-Probabilistic Shaped 64-QAM
2017 European Conference on Optical Communication (ECOC), 2017We present a novel format of combined geometric-probabilistic shaped QAM constellation. We measure about 1 dB sensitivity gain compared to conventional 64-QAM at 54.2 GBaud and 25% of overhead under different scenarios including back-to-back, single-channel and WDM transmissions.
Fanny Jardel +6 more
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A hybrid lightwave subcarrier CATV/16-QAM/16-QAM OFDM transmission system
Asia Communications and Photonics Conference 2013, 2013A hybrid lightwave subcarrier CATV/16-QAM/16-QAM orthogonal frequency-division multiplexing (OFDM) transmission system employing light injection/optoelectronic feedback techniques and photonic crystal fiber (PCF) is proposed and demonstrated. Good performance of carrier-to-noise ratio (CNR), composite second order, and composite triple beat were ...
Chia-Yi, Chen +5 more
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