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

Sharan, Nishant; Ghorai, S.K.

doi:10.1002/dac.4961

Cited by 11 publications

(13 citation statements)

References 31 publications

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“…The OSRAM SFH 4230 LED has been used for data transmission. The sixth order curve fitting approach, as outlined in previous works, matches the LED's V-I response curve [14,15]. The EVM is computed in the presence of an LED for five different bias voltages in the range of 1.6 V -1.7 V. Figure 4 (a) depicts the EVM performance of various NOMA DCO schemes at 1.6 V with input backoff power ranging from 0 to 8 dB.…”

Section: Resultsmentioning

confidence: 99%

“…This paper proposes a hybrid approach based on the union of a precoder and a µ-compander to lower the PAPR and reduce nonlinear characteristics in NOMA-based OFDM-VLC systems for 5G applications. Previously, we used the orthogonal multiplexing access (OMA) scheme to successfully implement the approach for PAPR reduction and nonlinearity mitigation in DCO-OFDM and ADO-OFDM systems [14,15]. The paper presents the extension of our work in [14].…”

Section: Introductionmentioning

confidence: 99%

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LED non-linearity mitigation in a NOMA-OFDM VLC system using a union of precoder and companding

Sharan

Ghorai²,

Kumar³

2022

Opt Quant Electron

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The power domain non-orthogonal multiple access (NOMA) has been considered as an outstanding candidate for 5G visible light communication networks. Due to the various salient features like robustness to multi-path fading, low latency, high compatibility with multiple input multiple output (MIMO) systems, etc. orthogonal frequency division multiplexing access (OFDM) is foreseen to exist in 5G systems. NOMA-based optical OFDM (O-OFDM) is expected to be a promising candidate for supporting high rate internet connectivity, especially for green indoor mobile networks. The OFDM waveform suffers from high PAPR issue. The high PAPR degrades the BER and also enhances the nonlinearity in an O-OFDM system. In this paper, a hybrid technique using a blend of precoder with compander is implemented to reduce the PAPR of NOMA based DC-biased O-OFDM (DCO-OFDM) system. The proposed NOMA DCO-OFDM system exhibits a low PAPR of only 4.3 dB. Also, for a reference bit error rate of 10 −4 , the proposed technique displays an error vector magnitude (EVM) of 13.2 dB.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

LED non-linearity mitigation in a NOMA-OFDM VLC system using a union of precoder and companding

Sharan

Ghorai²,

Kumar³

2022

Opt Quant Electron

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“…LED‐nonlinearity is an essential concern in VLC systems that reduces the performance of the transmitter 26 . The ADO‐OFDM signal can be distorted by the non‐linear behavior of the LED's current‐voltage (I‐V) transfer function, which can clip the higher peaks to the saturated value 16 . The I‐V characteristics of the LED can be expressed as 12 :

I_{normalLED} (V_{in}) = \{\begin{matrix} lmatrix \\ \frac{f (V_{in})}{{((), 1 goodbreak+ {(\frac{f ((), V_{in})}{I_{m}})}^{2 K_{f}})}^{\frac{1}{2}} K_{f}} if V_{in} \geq V_{italicTh} \\ 0 if V_{in} < V_{italicTh} \end{matrix}

where I LED is the LED current, V in is the LED input voltage, V th is turn‐on voltage, I m is the maximum allowable current in the LED, and K f is the non‐linearity factor.…”

Section: Ado‐ofdm System Modelmentioning

confidence: 99%

“…The higher PAPR of OFDM is another source of non‐linearity that creates non‐linear distortions of LED in the VLC system 26 . In References 16,18, many PAPR reduction methods have been proposed for use with ADO‐OFDM in VLC systems. However, the companding techniques have achieved the best PAPR reduction as a reference to the complementary cumulative distribution function (CCDF) of PAPR 18 .…”

Section: Ado‐ofdm System Modelmentioning

confidence: 99%

“…The spectral efficiency of ACO‐OFDM is less than that of DCO‐OFDM, but it has efficient optical power 9 . Asymmetrically biased DC‐biased O‐OFDM (ADO‐OFDM) was proposed to improve the performance of VLC by combing both ACO‐OFDM and DCO‐OFDM and reaping their benefits 9,14,16,17 . Our previous works 12,17,18 described ADO‐OFDM as a possible way to achieve VLC systems.…”

Section: Introductionmentioning

confidence: 99%

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Visible light communication performance using MIMO‐ADO‐OFDM system

Hameed

Abdulsatar

Sabri

2022

Trans Emerging Tel Tech

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Visible light communications (VLC) and optical orthogonal frequency division multiplexing (O-OFDM) have recently been identified as hopeful wireless techniques. Asymmetrically clipped DC-biased O-OFDM (ADO-OFDM)is a modern performance enhancement technology used in VLC. This article proposes a performance improvement model using a novel approach that collaborates with ADO-OFDM and multiple-input multiple-output (MIMO) in different design scenarios. In the first scenario, the bit-error-rate (BER) performance improvement is examined using different setups of MIMO-ADO-OFDM with maximal ratio combining (MRC). 8 × 8 MIMO good performance can be attained with about 15 dB signal-to-noise ratio for BER = 10 −4 . Another scenario is to boost the spectral efficiency of MIMO-ADO-OFDM by employing spatial multiplexing (SMX). However, 8 × 8 MIMO with SMX can improve spectral efficiency eight times that of single-input single-output ADO-OFDM by fragmenting source data into numerous independent data streams. In the last scenario, multi-user MIMO is developed by adopting ADO-OFDM with zero-forcing equalisers, allowing each user to consume all available bandwidth. The proposed technologies are evaluated by comparison with other MIMO systems, different O-OFDM, and under a non-linear LED model.

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An ADO‐OFDM with integrated precoding, companding and optimized power allocation methods for high‐speed data transmission in visible light communication

S.,

N. R.

2024

Trans Emerging Tel Tech

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Visible light communications (VLC) has received a lot of attention in recent studies because of its benefits over radio‐frequency (RF) communications. It is a short‐range optical wireless communication system that uses light‐emitting diodes (LEDs) as transmitters. Optical orthogonal frequency division multiplexing (OFDM) is an auspicious technology for VLC high‐speed data transfer. The use of OFDM in a VLC system raises the system's peak‐to‐average power ratio (PAPR). The intrinsic non‐linearity of LED is a key concern in an asymmetrically clipped DC‐biased optical OFDM (ADO‐OFDM) system due to its high PAPR. Also, conventional ADO‐OFDM modulation scheme cannot be used for accommodating different demands of services in downlink multiple access due to the restriction of direct current biased optical OFDM (DCO‐OFDM) and asymmetrically clipped optical (ACO‐OFDM) transmission on odd and even subcarriers. To tackle this issue, a modified ADO‐OFDM (MADO‐OFDM) is proposed that adjusts the numbers of subcarriers required for the transmission of ACO‐OFDM and DCO‐OFDM adaptively based on the requests of services in downlink multiple access. Also, the proposed MADO‐OFDM is integrated with a discrete Hartley Matrix transform (DisHMT) precoder and Generalized Piecewise Linear Compander (GPLD) to provide high‐speed data transmission with less PAPR. In addition, the power is allocated to the proposed MADO‐OFDM system optimally by maximizing the channel capacity based on the Aquila optimizer algorithm. The simulation results reveal that the suggested system's PAPR is reduced by 2.4 dB and 0.8 dB, respectively, compared to conventional ADO and hybrid ADO‐OFDM. It also confirms that the suggested generalized PLC can greatly increase BER without affecting the PAPR performance.

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

Cited by 11 publications

References 31 publications

LED non-linearity mitigation in a NOMA-OFDM VLC system using a union of precoder and companding

LED non-linearity mitigation in a NOMA-OFDM VLC system using a union of precoder and companding

Visible light communication performance using MIMO‐ADO‐OFDM system

An ADO‐OFDM with integrated precoding, companding and optimized power allocation methods for high‐speed data transmission in visible light communication

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