Efficient coding techniques for ADO-OFDM in IM/DD systems

Eltoukhi, Muhammed Abd El-Aziz; Abd‐Elnaby, Mohammed; El-Dolil, Sami A.; El‐Samie, Fathi E. Abd

doi:10.1007/s11107-018-0762-z

Cited by 7 publications

(5 citation statements)

References 20 publications

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“…A hybrid technique combines data arrangement between even and odd subcarriers, known as ADO-OFDM. It operates similarly to ACO-OFDM by utilizing the odd subcarriers, but it also incorporates even subcarriers, resembling DCO-OFDM [31]. Figure 4 provides an overview of the block diagram of ADO-OFDM.…”

Section: Ado-ofdmmentioning

confidence: 99%

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Optical-OFDM VLC System: Peak-to-Average Power Ratio Enhancement and Performance Evaluation

A. Zenhom,

Hamad,

Alghassab

et al. 2024

Sensors

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Visible Light Communication (VLC) systems are favoured for numerous applications due to their extensive bandwidth and resilience to electromagnetic interference. This study delineates various constructions of Optical Orthogonal Frequency Division Multiplexing (O-OFDM) approaches employed in VLC systems. Various factors are elaborated within this context to ascertain a more effective O-OFDM approach, including constellation size, data arrangement and spectral efficiency, power efficiency, computational complexity, bit error rate (BER), and peak-to-average power ratio (PAPR). This paper seeks to assess these approaches’ BER and PAPR performance across varying modulation orders. Regrettably, in VLC systems based on OFDM methodology, the superposition of multiple subcarriers results in a high PAPR. Therefore, this study aims to diminish the PAPR in VLC systems, enhancing system performance. We propose a non-distorting PAPR reduction technique, namely the Vandermonde-Like Matrix (VLM) precoding technique. The suggested technique is implemented across various O-OFDM approaches, including DCO-OFDM, ADO-OFDM, ACO-OFDM, FLIP-OFDM, ASCO-OFDM, and LACO-OFDM. Notably, this method does not affect the system’s data rate because it does not require the mandatory transmission of side information. Furthermore, this technique can decrease the PAPR without impacting the system’s BER performance. This study compares the proposed PAPR reduction technique against established methods documented in the literature to evaluate their efficacy and validity rigorously.

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Section: Ado-ofdmmentioning

confidence: 99%

“…𝑆(𝑊) is applied to H.S as denoted as 𝑋(𝐾). 𝑋(𝐾)is divided into two parts as dedicated in Equation ( 13) for odd subcarriers and Equation (14) for even subcarriers [31][32][33].…”

Section: Ado-ofdmmentioning

confidence: 99%

Optical-OFDM VLC System: Peak-to-Average Power Ratio Enhancement and Performance Evaluation

A. Zenhom,

Hamad,

Alghassab

et al. 2024

Sensors

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“…ConVolutional code is a kind of error-correcting code that is easy to implement based on logic operations. It is a channel coding technology and is widely used in digital communication systems [15].…”

Section: The Proposed Ber Enhancement Modelmentioning

confidence: 99%

“…ADO-OFDM has the same spectral efficiency as DCO-OFDM, but it has better optical power efficiency [14]. The Bit Error Rate (BER) of ACO-OFD is better than ADO and DCO-OFDM because it is independent of DC bias, where the DC bias value increases BER [15]. In [10], the authors presented the performance enhancement model for various O-OFDM based on the minimum mean square error equalizer and Hamming codes.…”

Section: Introductionmentioning

confidence: 99%

“…The simulation considers the LED nonlinearity for LOS and NLOS channels. The Rapps model is used for modeling the output current (I) to input Voltage (V) characteristic of LED, which describes the LED non-linearity [12][13][14][15]. The BER enhancement for VLC systems is proposed using a conVolutional encoder at the transmitter and the Vetribi decoder at the receiver.…”

Section: Introductionmentioning

confidence: 99%

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BER Comparison and Enhancement of Different Optical OFDM for VLC

Hameed¹,

Abdulsatar²,

Sabri³

2021

IJIES

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Visible Light Communication (VLC) becomes a promising technology in the Optical Wireless Communication OWC field. VLC has been developed based on Optical Orthogonal Frequency Division Multiplexing (O-OFDM) in recent years. The Bit Error Rate (BER) performance for various O-OFDM is studied in this paper. The non-linearity characteristic of Light-Emitting Diode (LED), modulation constellation size, O-OFDM scheme, and channel types impacts the BER performance of VLC systems significantly. The proposed model utilizes the conVolutional encoder of 2/3 rate and seven memory cells in the transmitter with O-OFDM for BER enhancement.At the receiver, the Viterbi algorithm system is employed with hard or soft-decision decoding. The proposed system is evaluated in Line-of-Sight and Non-Line-of-Sight (NLOS) channels. In the NLOS model, Zero Forcing Equalizer (ZFE) with channel estimation is added at the receiver path for equalizing the multipath diffused components. This study proves the capability of the proposed system in mitigating the LED non-linearity and reducing BER. The simulation results show the Signal-to-Noise Ratio (SNR) enhancement of the exanimated O-OFDM-based softdecision between 7 to 10 dB for the BER 10-5 in the LOS model, and for the NLOS model, the BER can be improved from 0.02 up to 10-5 at SNR 45dB.

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Throughput improvement and PAPR reduction for OFDM-based VLC systems using an integrated STC-IMADJS technique

Elbakry¹,

Mohammed

Ismail

2022

Opt Quant Electron

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Visible light communication (VLC) is a technology that is currently being employed to achieve high data rates. Orthogonal frequency division multiplexing (OFDM) is a powerful scheme for intensity modulation and direct detection (IM-DD) that is becoming increasingly important. OFDM systems based on VLC are accomplished through the implementation of IM-DD constraints, including direct current biased optical OFDM (DCO-OFDM), asymmetrically clipped optical OFDM (ACO-OFDM), and asymmetrically clipped DC-biased (ADO-OFDM), among others. The OFDM technique based on VLC is inefficient in terms of spectral efficiency and has a high peak to average power ratio (PAPR). In this article, the symbol time compression-image adjust (STC-IMADJS) technique will be proposed for throughput maximization and PAPR reduction in the DCO-OFDM, ACO-OFDM, and ADO-OFDM systems. Furthermore, the STC technique enables the simultaneous transmission of two sub-carriers through Walsh spreading codes without inference between them. As a result, the OFDM symbol has been reduced by 50%. The IMADJS strategy reduces the high PAPR of transmitted signals by compressing large signals and expanding small signals, as long as the average power level remains constant after compression. Therefore, the proposed STC-IMADJS technique doubles the throughput as well as significantly reduces the PAPR for OFDM systems based on VLC. The simulation results are performed using Matlab-2021a for 1024 sub-carriers. As a result, the simulation results show that the proposed technique reduces the PAPR by 3.7 dB ($$86\%$$ 86 % ), 8.16 dB ($$93\%$$ 93 % ), and 1.81 dB ($$20\%$$ 20 % ) for DCO-OFDM, ACO-OFDM, and ADO-OFDM systems respectively. Furthermore, the technique has a significantly lower computational complexity than conventional OFDM systems based on VLC. Finally, the measures of performance through this article are bit error rate and complementary cumulative distribution function.

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Efficient coding techniques for ADO-OFDM in IM/DD systems

Cited by 7 publications

References 20 publications

Optical-OFDM VLC System: Peak-to-Average Power Ratio Enhancement and Performance Evaluation

Optical-OFDM VLC System: Peak-to-Average Power Ratio Enhancement and Performance Evaluation

BER Comparison and Enhancement of Different Optical OFDM for VLC

Throughput improvement and PAPR reduction for OFDM-based VLC systems using an integrated STC-IMADJS technique

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