Performance Analysis of a 16-QAM Directly Modulated OFDM Visible Optical Wireless Link Without External Modulators

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Alhalabı M. Y. K.

Journal of Optics and Photonics Research, cilt.0, sa.0, ss.1-11, 2026 (Scopus)

Özet

This paper presents a performance analysis of a directly modulated direct-detection orthogonal frequency divisionmultiplexing-based visible light communication system designed for high-speed and low-complexity transmission. The proposed archi-tecture employs 16-Quadrature Amplitude Modulation (16-QAM) and achieves a data rate of 15 Gbps over a 500 m line-of-sight linkwhile eliminating the need for external optical modulatorsand transmission-line amplifiers. The system was modeled and evaluated intheThis paper presents a performance analysis of a directly modulated direct-detection orthogonal frequency divisionmultiplexing-based visible light communication system designed for high-speed and low-complexity transmission. The proposed archi-tecture employs 16-Quadrature Amplitude Modulation (16-QAM) and achieves a data rate of 15 Gbps over a 500 m line-of-sight linkwhile eliminating the need for external optical modulatorsand transmission-line amplifiers. The system was modeled and evaluated inthe OptiSystem environment using a 1024-point fast Fouriertransform with 512 active subcarriers, a cyclic prefix, and adirectly modu-lated laser operating at 550 nm. Performance was assessed in terms of bit error rate (BER), optical signal-to-noise ratio (OSNR), errorvector magnitude (EVM), maximum Q factor, and received optical power. The results show that the proposed architecture maintainsBER≤10−3when the OSNR is approximately 32 dB or higher, confirming thefeasibility of reliable 16-QAM orthogonal frequencydivision multiplexing (OFDM) transmission without external amplification. In addition, the analysis demonstrates that beam diver-gence is a critical design factor, since larger divergence angles reduce received optical power density and degrade both BER and EVM.A comparison between theoretical and simulated received power shows close agreement, validating the adopted link-budget model.The results confirm that the proposed dirThis paper presents a performance analysis of a directly modulated direct-detection orthogonal frequency divisionmultiplexing-based visible light communication system designed for high-speed and low-complexity transmission. The proposed archi-tecture employs 16-Quadrature Amplitude Modulation (16-QAM) and achieves a data rate of 15 Gbps over a 500 m line-of-sight linkwhile eliminating the need for external optical modulatorsand transmission-line amplifiers. The system was modeled and evaluated inthe OptiSystem environment using a 1024-point fast Fouriertransform with 512 active subcarriers, a cyclic prefix, and adirectly modu-lated laser operating at 550 nm. Performance was assessed in terms of bit error rate (BER), optical signal-to-noise ratio (OSNR), errorvector magnitude (EVM), maximum Q factor, and received optical power. The results show that the proposed architecture maintainsBER≤10−3when the OSNR is approximately 32 dB or higher, confirming thefeasibility of reliable 16-QAM orthogonal frequencydivision multiplexing (OFDM) transmission without external amplification. In addition, the analysis demonstrates that beam diver-gence is a critical design factor, since larger divergence angles reduce received optical power density and degrade both BER and EVM.A comparison between theoretical and simulated received power shows close agreement, validating the adopted link-budget model.The results confirm that the proposed directly modulated OFDM architecture provides an energy-efficient and cost-effective solutionfor short-to-medium-range high-speed visible optical wireless communication.ectly modulated OFDM architecture provides an energy-efficient and cost-effective solutionfor short-to-medium-range high-speed visible optical wireless communication. OptiSystem environment using a 1024-point fast Fouriertransform with 512 active subcarriers, a cyclic prefix, and adirectly modu-lated laser operating at 550 nm. Performance was assessed in terms of bit error rate (BER), optical signal-to-noise ratio (OSNR), errorvector magnitude (EVM), maximum Q factor, and received optical power. The results show that the proposed architecture maintainsBER≤10−3when the OSNR is approximately 32 dB or higher, confirming thefeasibility of reliable 16-QAM orthogonal frequencydivision multiplexing (OFDM) transmission without external amplification. In addition, the analysis demonstrates that beam diver-gence is a critical design factor, since larger divergence angles reduce received optical power density and degrade both BER and EVM.A comparison between theoretical and simulated received power shows close agreement, validating the adopted link-budget model.The results confirm that the proposed directly modulated OFDM architecture provides an energy-efficient and cost-effective solutionfor short-to-medium-range high-speed visible optical wireless communication.