• Chinese Optics Letters
  • Vol. 18, Issue 9, 090601 (2020)
Monette H. Khadr* and Hany Elgala
Author Affiliations
  • Electrical and Computer Engineering Department, University at Albany, New York 12222, USA
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    DOI: 10.3788/COL202018.090601 Cite this Article Set citation alerts
    Monette H. Khadr, Hany Elgala. Augmented communications: spectral efficiency and security enhanced visible light communications by design[J]. Chinese Optics Letters, 2020, 18(9): 090601 Copy Citation Text show less
    Block diagram detailing an ACom-based VLC system using OFDM, depicting the transmitter, receiver, and the optical channel in between.
    Fig. 1. Block diagram detailing an ACom-based VLC system using OFDM, depicting the transmitter, receiver, and the optical channel in between.
    Example of the time-domain representation of an ACom signal, with an IFFT length of 16. The construction is showing the parameters η and α and their effect on the generated signal s for a specific b.
    Fig. 2. Example of the time-domain representation of an ACom signal, with an IFFT length of 16. The construction is showing the parameters η and α and their effect on the generated signal s for a specific b.
    Simulation results depicting the relative spectral efficiency gain of ACom versus various system parameters. (a) Modulation order M at η=N=64, (b) IFFT length N at η=N and M=4, and (c) η for various M.
    Fig. 3. Simulation results depicting the relative spectral efficiency gain of ACom versus various system parameters. (a) Modulation order M at η=N=64, (b) IFFT length N at η=N and M=4, and (c) η for various M.
    BER versus SNR performance with the solid red line denoting the analytical performance and the remaining curves showing ACom at different γ for both the legitimate user (User) and the eavesdropper (Eve) at η=N=64.
    Fig. 4. BER versus SNR performance with the solid red line denoting the analytical performance and the remaining curves showing ACom at different γ for both the legitimate user (User) and the eavesdropper (Eve) at η=N=64.
    Effective SNR reduction versus γ showing that at γ=0.2 the effective SNR is reduced to only be 0.3 dB.
    Fig. 5. Effective SNR reduction versus γ showing that at γ=0.2 the effective SNR is reduced to only be 0.3 dB.
    Experimental setup of ACom using a USRP-N210 with two integrated daughterboards showing the optical frontends and the NUC used for ACom signal processing.
    Fig. 6. Experimental setup of ACom using a USRP-N210 with two integrated daughterboards showing the optical frontends and the NUC used for ACom signal processing.
    Experimental BER performance at 4-QAM with an IFFT length of 64 for the legitimate user at η=N, where γ=0 is equivalent to conventional DCO-OFDM transmission.
    Fig. 7. Experimental BER performance at 4-QAM with an IFFT length of 64 for the legitimate user at η=N, where γ=0 is equivalent to conventional DCO-OFDM transmission.
    Experimental BER performance of the eavesdropper as a function of η and γ at an SNR level of 20 dB at 4-QAM with an IFFT length of 64.
    Fig. 8. Experimental BER performance of the eavesdropper as a function of η and γ at an SNR level of 20 dB at 4-QAM with an IFFT length of 64.
    OFDM TechniqueSpectral Efficiency
    ACO-OFDMN/4log2M
    DCO-OFDMN/2log2M
    eU-OFDM[11]N/2log2M
    SEE-OFDM[12]3N/8log2M
    AComN/2log2M+N
    Table 1. Spectral Efficiency of Optical OFDM Techniques
    Monette H. Khadr, Hany Elgala. Augmented communications: spectral efficiency and security enhanced visible light communications by design[J]. Chinese Optics Letters, 2020, 18(9): 090601
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