A novel optical OFDM waveform design for visible light communication systems

Öz

In this study, a new spread-based optical OFDM waveform is proposed for intensity modulation/direct detection (IM/DD) communication systems. The proposed waveform is a combination of the spreading technique and the Flip OFDM waveform (Spread Flip OFDM, s-Flip OFDM). Simulation studies are carried out to evaluate the performance of the proposed waveform and compare it with optical OFDM waveforms such as Flip OFDM, DCO-OFDM and VLC-OFDM. In addition, the effect of the proposed spreading technique on other optical OFDM waveforms is analyzed in the presented study. It is understood that the proposed spreading technique provides a gain in the range of 5 to 10 dB SNR to the performance of optical OFDM waveforms in AWGN channel and diffused optical wireless channel environments, where ceiling bounce, exponential decay and exponential risen channel models are used. From the obtained numerical results, it is seen that the proposed s-Flip OFDM waveform is approximately 10 dB superior than the s-DCO-OFDM waveform and 15 dB superior than the s-VLC-OFDM waveform in both AWGN channel and diffused multipath optical channel environments.

Anahtar Kelimeler

• spread technique
• ceiling bounce optical channel model
• diffused multipath optical channel
• optical OFDM waveform
• IM/DD
• s-Flip OFDM waveform

Görünür ışık haberleşme sistemleri için yeni bir optik OFDM dalga formu tasarımı

Öz

Bu çalışmada, yoğunluk modülasyonu/doğrudan algılama (IM/DD) haberleşme sistemleri için yayma tabanlı yeni bir optik OFDM dalga formu önerilmektedir. Önerilen dalga formu yayma tekniği ile Flip OFDM dalga formunun birleşiminden oluşmaktadır (Spread Flip OFDM, s-Flip OFDM). Önerilen dalga formunun performansını değerlendirmek ve Flip OFDM, DCO-OFDM ve VLC-OFDM gibi optik OFDM dalga formları ile karşılaştırmak için benzetim çalışmaları yapılmaktadır. Ayrıca sunulan çalışmada, önerilen yayma tekniğinin diğer optik OFDM dalga formlarına etkisi analiz edilmektedir. AWGN kanal, tavan sıçrama, üstel azalan ve üstel artan kanal modellerinin kullanıldığı dağınık optik kablosuz kanal ortamlarında, önerilen yayma tekniğinin optik OFDM dalga formalarının performansına 5 ila 10 dB SNR aralığında kazanç sağladığı anlaşılmaktadır. Elde edilen nümerik sonuçlardan hem AWGN kanal ortamında hem de dağınık çok yollu optik kanal ortamlarında, önerilen s-Flip OFDM dalga formunun s-DCO-OFDM dalga formundan yaklaşık olarak 10 dB ve s-VLC-OFDM dalga formundan da 15 dB daha iyi olduğu görülmektedir.

Anahtar Kelimeler

• Yayma tekniği
• tavan sıçrama optik kanal modeli
• dağınık çok yollu optik kanal
• optik OFDM dalga formu
• IM/DD
• s-Flip OFDM dalga formu

Kaynakça

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