Yazar "Kepezkaya, Talat" seçeneğine göre listele

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    Öğe
    A Novel DC Biasless Optical OFDM Waveform Design
    (Ieee, 2023) Kepezkaya, Talat; Ozen, Ali
    As a solution to the energy inefficiency problem of DC biased optical OFDM (DCO-OFDM) waveform, one of the optical OFDM (O-FDM) waveforms developed for new generation optical wireless communication systems, DC bias-free DCO-OFDM (DC Biasless O-OFDM) waveform is suggested by this study. The proposed waveform is compared with DCO-OFDM, NDC-O-OFDM and ACO-OFDM waveforms in AWGN and flat optic LOS channel environments over the BER-SNR and SE-SNR performance criteria. From the acquired performances, it is perceived that the recommended DC Biasless O-OFDM waveform gives an SNR gain of approximately 8 to 13 dB at 1E-4 BER value without sacrificing the spectral efficiency.
  • [ X ]
    Öğe
    Improving the BER and PAPR performances of optical OFDM with lazy lifting wavelet transform
    (Springer, 2023) Kepezkaya, Talat; Ozen, Ali
    Visible light communication (VLC), which is seen as an alternative and complementary technology to radio frequency (RF) communication systems, has emerged as a promising new generation system. Because of its potential to combat inter-symbol interference (ISI), orthogonal frequency division multiplexing (OFDM) has been validated as the best candidate for high-speed optical wireless communications (OWC). Asymmetrically clipped optical OFDM (ACO-OFDM), DC-biased optical OFDM (DCO-OFDM), and Flip-OFDM, which are made suitable for intensity modulation/direct detection (IM/DD) systems, are unipolar OFDM schemes widely accepted for OWC in the literature. In this study, it is proposed to combine the lifting wavelet transform (LLWT), which uses the lazy wavelet, with these three optical OFDM waveforms to increase the performance of the ACO-OFDM, DCO-OFDM, and Flip-OFDM systems proposed for OWC systems. In the environment where M-level color shift keying (M-CSK) and M-level quadrature amplitude modulation (M-QAM) modulations are used, proposed waveforms are tested with computer simulations for bit error rate (BER) and peak average power ratio (PAPR) performance measures. From the obtained simulation results, it is observed that the proposed transform technique performs an approximately 6 dB SNR improvement on the waveforms investigated in this study in both modulation methods for the 1E-4 BER value.