Design of Cyclic Shifted PAM-DMT Signals in HACO-OFDM Visible Light Communication

Hu, Wei-Wen

doi:10.1109/lcomm.2020.3019051

Cited by 7 publications

(6 citation statements)

References 15 publications

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“…The complexity of the OFDM-based system is dominated by IFFT/FFT, while the complexity of other operations can be negligible [21]. Therefore, the computational complexity of the IFFT/FFT operations is analyzed to characterize the complexity of the proposed scheme.…”

Section: Complexity Analysismentioning

confidence: 99%

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Reconstructed Hybrid Optical OFDM-NOMA for Multiuser VLC Systems

Shi

Feng

2022

Photonics

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Non-orthogonal multiple access (NOMA) is deemed to be a prospective multiple access technology of the next generation. However, in visible light communication (VLC), when advanced hybrid optical orthogonal frequency division multiplexing (O-OFDM), such as hybrid asymmetrically clipped O-OFDM (HACO-OFDM), is combined with NOMA, error propagation is induced, which degrades the system performance. Therefore, a novel reconstructed hybrid O-OFDM-NOMA (RHO-OFDM-NOMA) scheme is conceived in this paper. In order to eliminate the error propagation, the users in RHO-OFDM-NOMA opt for the ACO-OFDM or clipping-free O-OFDM signals according to their channel qualities, which are subsequently superimposed on pulse-amplitude-modulated discrete multitone (PAM-DMT) to yield the spectrum-efficient hybrid O-OFDM signal. Furthermore, a reconstruction process is designed to ensure the non-negativity. Compared with HACO-OFDM, the proposed RHO-OFDM can retain the error propagation in NOMA-VLC, whilst maintaining the superiorities of high spectral and power efficiency. It is demonstrated by simulation results that RHO-OFDM-NOMA can support a notably higher data rate than the NOMA schemes using conventional O-OFDM.

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Section: Complexity Analysismentioning

confidence: 99%

“…Compared with conventional schemes, HACO-OFDM can achieve substantial improvement of the spectral efficiency, whist maintaining high power efficiency. Therefore, HACO-OFDM has been widely applied in various scenarios of VLC [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Reconstructed Hybrid Optical OFDM-NOMA for Multiuser VLC Systems

Shi

Feng

2022

Photonics

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“…The nonlinear outcomes of LEDs can be mitigated either by lowering power backoff values using PAPR reduction techniques or by directly increasing the linear region of input and output signal of V – I characteristics of LED. Some PAPR reduction strategies have been probed to curb the LED's nonlinearity in OFDM‐based VLC systems 22–28 . Hu 22 and Binita and Hema 23 have proposed PAPR reduction techniques in a HACO system.…”

Section: Introductionmentioning

confidence: 99%

“…Some PAPR reduction strategies have been probed to curb the LED's nonlinearity in OFDM‐based VLC systems 22–28 . Hu 22 and Binita and Hema 23 have proposed PAPR reduction techniques in a HACO system. In Hu, 22 cyclic shifted PAM‐DMT method is proposed to reduce the PAPR in a HACO system.…”

Section: Introductionmentioning

confidence: 99%

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Hybrid scheme of precoder with μ‐law compander for PAPR reduction and nonlinearity improvement in ADO‐OFDM system

Sharan

Ghorai

2021

Int J Communication

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Summary The application of orthogonal frequency division multiplexing (OFDM) in a visible light communication (VLC) system increases the peak‐to‐average power ratio (PAPR) of the system. Owing to high PAPR, the intrinsic nonlinearity of LED is an important issue in an asymmetrically clipped DC‐biased optical OFDM (ADO‐OFDM) system. In this paper, a hybrid scheme is proposed to reduce the PAPR as well as to mitigate the nonlinearity in an ADO‐OFDM system. The proposed method is a combination of two ADO‐OFDM formats: precoded ADO‐OFDM and μ‐ADO‐OFDM. The preprocessing of the input using a predetermined matrix (PM) in the precoder relieves the need for a handshake at the receiver. The compression of the peak values and enhancement of low amplitudes of the precoded signal in the time domain yield a low PAPR of 2.4 dB only. Besides PAPR reduction, the union of precoder and compander boosts the bit error rate (BER) performance of the traditional ADO‐OFDM system for μ≤128. The combination of precoder with compander decreases the power requirements for high bit rate transmission for a reference BER of 10−3. In this work, nonlinearity is quantified in terms of error vector magnitude (EVM) in percent. The hybrid scheme shows an EVM of 17.23% for 0 dB input backoff power (IBO) much less than 66.4% EVM for a simple ADO‐OFDM system. In addition to low PAPR and mitigation of nonlinearity, the proposed method shows the improvement in power spectral density (PSD) of the system.

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