• Chinese Optics Letters
  • Vol. 20, Issue 5, 050601 (2022)
Gang Chen, Ming Chen*, Wen Chen, Lede Yin, Aitao Deng, Yuxin Cai, and Dengqiao Wang
Author Affiliations
  • School of Physics and Electronics, Hunan Normal University, Changsha 410081, China
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    DOI: 10.3788/COL202220.050601 Cite this Article Set citation alerts
    Gang Chen, Ming Chen, Wen Chen, Lede Yin, Aitao Deng, Yuxin Cai, Dengqiao Wang. Real-time reception of NHS-OFDM signal with SPA-enhanced channel estimation for intensity-modulated direct-detection systems[J]. Chinese Optics Letters, 2022, 20(5): 050601 Copy Citation Text show less

    Abstract

    In this Letter, we have experimentally verified a low-complexity subcarrier pairwise-averaging (SPA)-enhanced channel estimation (CE) method for small-size fast Fourier transform (FFT) non-Hermitian symmetric orthogonal frequency-division multiplexing (NHS-OFDM) transceivers. Compared with intra-symbol frequency averaging (ISFA), more than 20% look-up tables and 10% logic power consumption can be saved. The least-square (LS), ISFA, and SPA CE methods are compared by offline and real-time digital signal processing approaches. The results show that the receiver sensitivity of the SPA NHS-OFDM transmission system with 64/128-point FFT can be improved by more than 1 dB at the bit error rate of 3.8 × 10-3 compared to the LS.
    t^re(n)=tre(n)h(n)+wre(n),

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    t^im(n)=tim(n)h(n)+wim(n),

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    t^(n)=t^re(n)+jt^im(n).

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    T^(k)=FFT{t^(n)}=FFT{t^re(n)}+jFFT{t^im(n)}=12[T(k)+T*(k)]·H(k)+Wre(k)+j{12j[T(k)T*(k)]·H(k)+Wim(k)}=T(k)H(k)+Wre(k)+jWim(k),

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    H^LS(k)=T^(k)T(k)=H(k)+Wre(k)+jWim(k)T(k),

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    H^LS(k)=H*(k)+Wre*(k)+jWim*(k)T(k).

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    H^ISFA(k)={1AB+1k=BAH^LS(k),k[kmax,kmin]1CD+1k=DCH^LS(k),k[kmin,kmax]A=min(kmin,k+m)B=max(kmax,km)C=min(kmax,k+m)D=max(kmin,km).

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    H^SPA(k)=H^SPA*(k)=H^LS(k)+H^LS*(k)2.

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    H^SPA(k)={H(k)±Wre(k),TTS(k)=TTS(k)H(k)±jWim(k),TTS(k)=TTS(k).

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    Gang Chen, Ming Chen, Wen Chen, Lede Yin, Aitao Deng, Yuxin Cai, Dengqiao Wang. Real-time reception of NHS-OFDM signal with SPA-enhanced channel estimation for intensity-modulated direct-detection systems[J]. Chinese Optics Letters, 2022, 20(5): 050601
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