Results 141 to 150 of about 3,362 (185)
Some of the next articles are maybe not open access.
2007 IEEE International Conference on Communications, 2007
In this paper, we investigate block-coded QAM constructed by multilevel coding for the noncoherent generalized likelihood ratio test (GLRT) detector. For the AWGN channel, we derive a new GLRT detector and the corresponding distance. The minimum noncoherent distance of block-coded QAM is derived and two construction of noncoherent block-coded QAM (NBC ...
Ruey-Yi Wei +3 more
openaire +1 more source
In this paper, we investigate block-coded QAM constructed by multilevel coding for the noncoherent generalized likelihood ratio test (GLRT) detector. For the AWGN channel, we derive a new GLRT detector and the corresponding distance. The minimum noncoherent distance of block-coded QAM is derived and two construction of noncoherent block-coded QAM (NBC ...
Ruey-Yi Wei +3 more
openaire +1 more source
Multimode modulation and coding of QAM
IEEE Transactions on Communications, 1993A general-purpose modulation and coding implementation that is based on the quadrature amplitude modulation (QAM) family of modulation is described. The technique utilizes the 'superposed' property of certain rectangular QAM constellations, along with the fact that optimal four-state trellis codes for such constellations are essentially identical, to ...
Hong Y. Chung, Stephen G. Wilson
openaire +2 more sources
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
openaire +1 more source
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
openaire +1 more source
Linearity Requirements of QAM Transmitters
Optical Fiber Communication Conference, 201516, 64QAM, and higher-modulation formats impose strict linearity requirements on the modulator-driver response. We experimentally demonstrate the relation between transmitter nonlinearity and OSNR penalty. Simulations confirm experimental data for a wide range of harmonic distortion.
Stuart Hughes +5 more
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
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.
openaire +1 more source
Further Results on Adaptive Equalizer Improvements for 16 QAM and 64 QAM Digital Radio
IEEE Transactions on Communications, 1986Channel distortions due to multipath fading are a principal source of outage for high-capacity digital radio. Time domain equalization is increasingly becoming an effective means to compensate for fading induced ISI. This paper compares the performance of transversal and decision feedback equalizers used for 16 QAM and 64 QAM digital radio systems. The
Mansoor Shafi, David J. Moore
openaire +1 more source