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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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Optimization of Linearly Equalized QAM
IEEE Transactions on Communications, 1987A QAM signal transmitted over a channel with linear distortion and additive white Gaussian noise can be linearly equalized at the receiver to eliminate intersymbol interference. If the QAM signal is power constrained and a given symbol error rate is required, we show that it is possible to maximize the bit rate of this system by optimizing the symbol ...
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IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 2000
A multicarrier quadrature amplitude modulation (QAM) modulator has been developed and implemented with programmable logic devices. The multicarrier QAM modulator contains four CORDIC-based QAM modulators. A conventional QAM modulator needs two multipliers, one adder, and sine/cosine ROM's.
J. Vankka +3 more
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A multicarrier quadrature amplitude modulation (QAM) modulator has been developed and implemented with programmable logic devices. The multicarrier QAM modulator contains four CORDIC-based QAM modulators. A conventional QAM modulator needs two multipliers, one adder, and sine/cosine ROM's.
J. Vankka +3 more
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2002
Bandwidth efficient communication systems employ highorder modulation schemes like M-ary QAM modulation for reasons of spectral efficiency. Many sophisticated signal processing algorithms are implemented in a QAM demodulator, including adaptive equalization, timing recovery, carrier recovery, automatic gain control and digital down conversion to name a
Chris Dick, Fred Harris 0001
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Bandwidth efficient communication systems employ highorder modulation schemes like M-ary QAM modulation for reasons of spectral efficiency. Many sophisticated signal processing algorithms are implemented in a QAM demodulator, including adaptive equalization, timing recovery, carrier recovery, automatic gain control and digital down conversion to name a
Chris Dick, Fred Harris 0001
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Error statistic of QAM channel in AM/QAM hybrid optical transmission
IEEE Photonics Technology Letters, 1996The error statistic of the QAM channel in an AM/QAM hybrid optical transmission system is measured. Errors occur randomly in optical transmission without clipping. However, errors are found to occur in bursts when the impulsive noise due to clipping degrades the QAM signal's BER.
K. Maeda, K. Utsumi, K. Fujito
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Phase noise effects in QAM systems
Proceedings of 8th International Symposium on Personal, Indoor and Mobile Radio Communications - PIMRC '97, 2002The effects of oscillator phase noise on the performance of digital transmission systems employing QAM are investigated. The model used for the phase noise is a Wiener-Levy process which allows a moment characterization of the filtered phase noise.
CORVAJA, ROBERTO, PUPOLIN, SILVANO
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Performance of block turbo coded 16-QAM and 64-QAM modulations
Proceedings of GLOBECOM '95, 2002We present the results of our investigation concerning the performance of block turbo codes associated with high spectral efficiency QAM modulations. By using a pragmatic approach, simulation results show that all the block turbo coded QAM modulations we have tested are at 2.9/spl plusmn/0.2 dB of their Shannon's limit.
R. Pyndiah, A. Picart, A. Glavieux
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