Results 141 to 150 of about 46,201 (198)

Odd-bit triangular quadrature amplitude modulations

2009 IEEE 20th International Symposium on Personal, Indoor and Mobile Radio Communications, 2009
Adaptive modulation is a technique which alters constellation size depending on channel condition to achieve highspeed data transmission. However, the well-known modulation schemes transmitting odd bits per symbol, such as 8-ary phase shift keying (PSK) and cross quadrature amplitude modulation (cross QAM), are generally not considered as a candidate ...
Sung-Joon Par, Moo-Kwang Byeon, Jun-Ho Jeon   +2 more
  +4 more sources

Weighted-Quadrature-Amplitude Modulation

IEEE Transactions on Electromagnetic Compatibility, 1986
A family of weighted-quadrature-amplitude-modulation (WQAM) schemes is introduced and analyzed. One of the staggered WQAM (SWQAM) schemes has low spectral sidelobes, even after hardlimiting, and its performance in an adjacent-channel interference (ACI) environment is superior to that of the QPSK; SQPSK, MSK, and SQORC.
Andy D. Kucar, Kamilo Feher
openaire   +1 more source

Quadrature Amplitude Modulation

2019
The Quadrature Modulation Scheme (QUAM) uses sine and cosine orthogonality properties to allow the transmission of two different signals in the same carrier, which occupies a bandwidth that is equivalent to the AM signal. The QUAM modulator can be assembled using two DSB-SC modulators.
Marcelo S. Alencar, Valdemar C. da Rocha
openaire   +1 more source

Hexagonal Quadrature Amplitude Modulation Aided Spatial Modulation

2019 11th International Conference on Electrical and Electronics Engineering (ELECO), 2019
In this study, a new multiple-input multiple-output (MIMO) transmission scheme with energy-efficiency is proposed by combining spatial modulation (SM) and energy-efficient hexagonal quadrature amplitude modulation (HQAM) constellation scheme, briefly called HQAM-SM.
Fatih Cogen, Erdogan Aydin
openaire   +1 more source

Polarized light by quadrature amplitude modulation

Optics and Lasers in Engineering, 2013
Abstract A new method to create elliptically polarized light based on the quadrature amplitude modulation is proposed. This method begins from an unpolarized light and does not use any classical methods, as for instance those using polarizers and retarders or also by refraction, scattering, dichroism or birefringence effects.
Cruz Meneses-Fabian, Uriel Rivera-Ortega
openaire   +2 more sources

Flexible Quadrature Spatial Pulse Amplitude Modulation for VLC Systems

IEEE Systems Journal, 2022
Quadrature-spatial modulation (QSM) offers high spectral efficiency (SE) without interchannel interference for both radio frequency and visible light communication (VLC) systems. In this article, a new QSM scheme called flexible quadrature spatial pulse amplitude modulation (FQSPAM) is proposed for VLC systems.
Yasin Celik, Sultan Aldirmaz-Colak, Ertugrul Basar   +2 more
openaire   +3 more sources

Triangular Quadrature Amplitude Modulation

IEEE Communications Letters, 2007
The square quadrature amplitude modulation (QAM) has been widely used for decades. Though it is not optimum in the sense of power efficiency, simple detection makes it in use for numerous digital communication systems deploying high-order modulation. In this paper, we propose new signal sets which make an effective use of limited power resource.
openaire   +1 more source

Quadrature Null Effect in Amplitude Modulation

International Journal of Technology, 2017
Quadrature null effect (QNE) is a phenomenon in amplitude modulation (AM) demodulator circuit arise if carrier signal generated from local oscillator is not synchronized in phase with input signal. Our main motive is to synchronize phase in this effect by various synchronizing techniques so as to reconstruct input modulated signal completely, are ...
Archi Jain, Divanshu Chhabra
openaire   +1 more source

Jointly optimized quadrature amplitude modulation

2016 IEEE International Conference on Communications (ICC), 2016
Quadrature amplitude modulation has been widely used for high-speed data transmission in modern digital communication systems. In this work, a generalized quadrature amplitude modulation which relaxes the constraint of square lattice is suggested to improve the joint performance of modulation and coding.
openaire   +1 more source

Single sideband quadrature amplitude modulation

Radioelectronics and Communications Systems, 2017
Anew modulation scheme—single sideband quadrature amplitude modulation (SSB QAM) is proposed. This scheme allows to decrease the spectral width of the transferred signal by two times as opposed to the traditional quadrature amplitude modulation, while maintaining its spectral efficiency.
openaire   +2 more sources