Visible Light Communication: An Investigation of LED Non-Linearity Effects on VLC Utilising C-OFDM

Abdulwali, Jummah; Boussakta, S.

doi:10.3390/photonics9030192

Cited by 7 publications

(3 citation statements)

References 26 publications

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“…In an OWC system, especially an OCC system, the signals are encoded according to the intensity of the light sources, and nonnegative values are required. Thus, the OFDM signal should be preprocessed before applying the inverse discrete FT. At present, asymmetrically clipped optical OFDM (ACO-OFDM) and DC-biased optical OFDM (DCO-OFDM) are two popular technologies for VLC/LiFi systems [ 24 , 25 ]. Regardless, compared with the FT, the wavelet OFDM provides many advantages, such as no redundancy in the CP, decreased subchannel interference, and increased spectral separation.…”

Section: System Architecturementioning

confidence: 99%

Design and Implementation of a Hybrid Optical Camera Communication System for Indoor Applications

Nguyen,

Le,

et al. 2024

Sensors

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Optical wireless communication is a promising emerging technology that addresses the limitations of radio-frequency-based wireless technologies. This study presents a new hybrid modulation method for optical camera communication (OCC), which integrates two waveforms transmitted from a single transmitter light-emitting diode (LED) and receives data through two rolling shutter camera devices on the receiver side. Then, a smart camera with a high-resolution image sensor captures the high-frequency signal, and a low-resolution image sensor from a smartphone camera captures the low-frequency signal. Based on this hybrid scheme, two data streams are transmitted from a single LED, which reduces the cost of the indoor OCC device compared with transmitting two signals from two different LEDs. In the proposed scheme, rolling-shutter orthogonal frequency-division multiplexing is used for the high-frequency signals, and M-ary frequency-shift keying is used for the low-frequency signals in the time domain. This proposed scheme is compatible with smartphone and USB cameras. By controlling the OCC parameters, the hybrid scheme can be implemented with high performance for a communication distance of 10 m.

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Section: System Architecturementioning

confidence: 99%

Design and Implementation of a Hybrid Optical Camera Communication System for Indoor Applications

Nguyen,

Le,

et al. 2024

Sensors

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“…Symbols are separately modulated for each user, and individual users of transmitting symbols are randomly generated [21]- [23]. Constellation symbols are applied for DCTM pre-coding.…”

Section: B Discrete Cosine Transform -Domain Conversionmentioning

confidence: 99%

Enhanced Artificial Bee Colony, Square Root Raised Cosine Precoding, and Mu law Compandor for Optimization of MIMO-OFDM System

Azeez¹,

Tarannum²

2023

Int. J. Adv. Sci. Eng. Inf. Technol.

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The efficiency and high-speed data transfer rate of the communication system are increased based on Orthogonal Frequency Division Multiplexing (OFDM). The existing research in OFDM involves applying optimization methods to improve the system's efficiency. The high Peak Average Power Ratio (PAPR) value is a major limitation in the OFDM system, and this provides distortion due to the non-linear High-Power Amplifier (HPA). Local optima trap and lower convergence are two main limitations in existing optimization methods. This research proposes Enhanced Artificial Bee Colony (ABC) optimization method with a precoding-compandor technique to increase the efficiency of the OFDM system. Enhanced ABC method is applied with Boltzmann search to increase the exploitation capacity of the optimization efficiency. The selective mapping technique is applied to transform the candidate signal in the system. The ABC method increases exploration, and Boltzmann search increases exploitation. The enhanced ABC method increases the exploitation process that helps to overcome local optima traps and lower convergence. Square Root Raised Cosine (SRRC) precoding and Mu law compandor techniques were applied to reduce the PAPR. The Discrete Cosine Transform (DCT) technique is applied for domain conversion in the OFDM system. The proposed method has a convergence rate of 6.4069, and the existing one has a 6.4033 convergence rate. The enhanced ABC method provides higher efficiency in the MIMO-OFDM system regarding Symbol Error Rate (SER), PAPR, and Bit Error Rate (BER).

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“…Furthermore, VLC has several advantages including high security, huge unregulated bandwidth (400-789 THz), high energy efficiency, low cost and high electromagnetic interference immunity [4]. Despite the tremendous bandwidth of VLC, the limited modulation bandwidth of LEDs (few MHz) limits the full exploitation of VLC potential [5]. In order to effectively overcome this challenge, the application of multiple-input multiple-output (MIMO) and advanced multiple access techniques are proposed [6,7].…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of Power Allocation and User-Pairing Techniques for MIMO-NOMA in VLC Systems

Ibrahim,

Abaza,

Mansour

et al. 2024

Photonics

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In this paper, we evaluate the performance of multiple-input multiple-output (MIMO) communication systems applied with a non-orthogonal multiple access (NOMA)-based indoor visible light communication (VLC). We present two efficient user-pairing algorithms for NOMA in VLC, aiming to enhance achievable data rates effectively. Our investigation involves the application of three low-complexity power allocation techniques. Comparative analysis reveals performance enhancements when employing the proposed schemes, especially when contrasted with NOMA without user pairing and orthogonal frequency division multiple access (OFDMA). Additionally, we explore the performance of both algorithms in scenarios with both even and odd numbers of users. Simulation results demonstrate the superiority of NOMA in comparison to OFDMA.

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Visible Light Communication: An Investigation of LED Non-Linearity Effects on VLC Utilising C-OFDM

Cited by 7 publications

References 26 publications

Design and Implementation of a Hybrid Optical Camera Communication System for Indoor Applications

Design and Implementation of a Hybrid Optical Camera Communication System for Indoor Applications

Enhanced Artificial Bee Colony, Square Root Raised Cosine Precoding, and Mu law Compandor for Optimization of MIMO-OFDM System

Performance Analysis of Power Allocation and User-Pairing Techniques for MIMO-NOMA in VLC Systems

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