Performance analysis of NLOS ultraviolet communications with correlated branches over turbulent channels

Garg, Kamal; Singya, Praveen Kumar; Bhatia, Vimal

doi:10.1364/jocn.11.000525

Cited by 21 publications

(7 citation statements)

References 22 publications

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“…For the first time, for a mixed RF/free space optics (FSO) based relay network, the superiority of HQAM is verified through the results obtained in [117]. Further, [118]- [120], authors have justified HQAM superiority in NLoS ultraviolet communication (UVC) based relay networks.…”

Section: Comparison Of Irregular Hqam Constellation With Other Qammentioning

confidence: 85%

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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: Comparison Of Irregular Hqam Constellation With Other Qammentioning

confidence: 85%

“…In recent years, UV NLoS communication has gained prominence, several notable works were performed employing QAM constellations to improve the spectral efficiency [118], [119], [368]- [378]. In [117], [356], [371], [379]- [387], authors have presented the application of QAM and adaptive modulation in FSO communications.…”

Section: Spatial Diversitymentioning

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.

Self Cite

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“…At present, most of the research work related to UVC systems focuses on establishing UVC channel models [8], [9], studying channel characteristics [10], examining noise components, and exploring signal-to-noise (SNR) estimation methods. In UVC systems, noise can cause serious interference to signal; therefore, extensive research has been conducted on noise-related issues to improve communication performance.…”

Section: Introductionmentioning

confidence: 99%

Noise Reduction on Received Signals in Wireless Ultraviolet Communications Using Wavelet Transform

et al. 2020

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In wireless ultraviolet optical communications, noise is one of the most essential factors affecting the communication system performance. This paper presents a scheme of reducing noise in the received ultraviolet signal using wavelet transform algorithms. An effective signal-to-noise ratio (SNR) calculation method for the received signals is also proposed, and adopted by our wavelet denoising scheme so that an optimal wavelet basis function can be selected. The proposed denoising method is applied to both the ultraviolet signals generated from the multi-scattering transmission simulation model and the signals received from physical experiments, under different conditions of transceiver elevation angles and communication distances. The results show consistently that the wavelet transform algorithm can significantly improve the SNRs at the receiving end. When the wavelet basis is coif2, the best denoising effect is achieved where the improved SNR reaches 11.9925 dB on average for various physical conditions. INDEX TERMS Ultraviolet optical communication, scattering transmission, Wavelet transform, signal-tonoise ratio, signal denoising.

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“…To overcome the limitation of severe fading in turbulence channel, more sophisticated UV communication systems were proposed [5]- [10]. Particularly, in [5], to extend the NLOS link range in Gamma-Gamma distributed turbulence fading, a receiver diversity scheme was reported.…”

Section: Introductionmentioning

confidence: 99%

“…A cooperative based decode-andforward relay-assisted NLOS UV communication system over log-normal distributed fading was reported in [9], where the outage analysis based on the best relay selection adaptive to the channel conditions was addressed. A spatial diversity scheme with selection combing was proposed with log-normal distributed channel [10]. The authors considered rectangular quadrature amplitude modulation (RQAM), cross-QAM, and hexagonal QAM modulation schemes and carried out the outage and error rate analysis.…”

Section: Introductionmentioning

confidence: 99%

Multiuser Interference-Limited Petahertz Wireless Communications Over Málaga Fading Channels

Arya

Chung

2020

IEEE Access

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Petahertz frequency bands have a unique characteristic of atmospheric scattering that enables non-line-of-sight (NLOS) communications. In this paper, we analyze the performance of petahertz wireless communications (PWC) with a novel statistical model derived over a multiuser interferencelimited optical turbulence channel. Specifically, we derive a novel probability density function of the received signal-to-interference ratio when the distribution of the received signal is quantified with each scattered path following a Málaga distribution. Moreover, novel closed-form expressions for the outage and the bit error probabilities are derived in the interference-limited PWC. The outage performance is evaluated over non-identical Málaga fading channels, where the fading characteristics of the transmitter and the interferer are different. We also investigate the achievable capacity of the multiuser interference-limited PWC over Málaga fading channels. The analytical results obtained are corroborated with simulation results. It is shown that the analysis performed with the proposed statistical model is reliable and accurate and thus the statistical model can be useful for emerging multiuser interference-limited petahertz wireless communications.INDEX TERMS Optical communications, outage probability, signal-to-interference ratio, turbulence fading.

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Performance analysis of NLOS ultraviolet communications with correlated branches over turbulent channels

Cited by 21 publications

References 22 publications

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

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

Noise Reduction on Received Signals in Wireless Ultraviolet Communications Using Wavelet Transform

Multiuser Interference-Limited Petahertz Wireless Communications Over Málaga Fading Channels

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