The Operation of Dual Polarized QAM Systems in the Presence of Depolarization Crosstalk and Differential Fading

Duvoisin, P.F.; Hsieh, S. Tonia; Williamson, E.P.

doi:10.1109/jsac.1987.1146552

Cited by 2 publications

(1 citation statement)

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“…In [159], authors reviewed the importance of coded modulation for a 1.544 Mbps data-rate in voice modems employing 256-QAM. In [160], authors presented the performance of a dual polarized M -ary QAM up-to 64 levels by considering coherence between cross talk and the desired signal. In [161], authors proposed an equalization technique for multilevel QAM systems which eliminates linear distortions with easy implementation at high data-rates.…”

Section: A Mobile Communicationsmentioning

confidence: 99%

A Survey on Higher-Order QAM Constellations: Technical Challenges, Recent Advances, and Future Trends

Singya

Shaik

Kumar

et al. 2021

IEEE Open J. Commun. Soc.

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Communication system's performance is sensitive to bandwidth, power, cost etc. There have been various solutions to improve the performance, out of them, one of the fundamental solutions over the years is design of optimum modulation schemes. As the research on beyond 5G heats up, we survey and explore power and bandwidth efficient modulation schemes for the next generation communication systems in details. In the existing literature, initially square quadrature amplitude modulation (SQAM) was considered. However, only square constellations are not sufficient for varying channel conditions and rate requirements, thus, efficient odd power of 2 constellations were introduced. For odd power of 2 constellations, rectangular QAM (RQAM) is most commonly used. However, RQAM is not a good choice and modified cross QAM (XQAM) constellation is preferred which provides improved power efficiency over RQAM due to its energy efficient two dimensional (2D) structure. The increasing demand for high data-rates has further encouraged research towards more compact 2D constellations which leads to hexagonal lattice structure based hexagonal QAM (HQAM) constellations. In this work, various QAM constellations are discussed and detailed study of star QAM, XQAM, and HQAM is presented. Generation, peak and average energies, peak-to-average-power ratio, symbol-error-rate, decision boundaries, bit mapping, Gray code penalty, and bit-error-rate of star QAM, XQAM, and HQAM constellations for different constellation orders are presented. Finally, a comparative study of various QAM constellations is presented which justifies the supremacy of HQAM over other QAM constellations for various wireless communication systems and a potential modulation scheme for future standards.

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Section: A Mobile Communicationsmentioning

confidence: 99%