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access icon free LED non-linearity mitigation techniques for optical OFDM-based visible light communications

The visible light communication (VLC) utilising the light emitting diodes (LEDs) as transmitters has gained much interest for the indoor wireless access due to its abundance of unregulated spectrum. However, the LED non-linearities cause a detrimental non-linear distortion especially for the adoption of optical orthogonal frequency-division multiplexing (O-OFDM), which is known to suffer high peak-to-average power ratio (PAPR). Specifically, the authors consider the direct current biased O-OFDM (DCO-OFDM) to realise the O-OFDM signals. This study aims to develop the mitigation techniques for LED non-linearities at transmitter through the combined advantages of PAPR reduction and the technique of linearising the non-linear LED characteristics. The orthogonal cover code sequence is exploited to design a transform precoding to reduce the PAPR. An uncomplicated pre-distorter at transmitter is adopted to linearise the LED non-linearity. In addition, the authors propose a dynamic DC biasing method to avoid the clipping noise in DCO-OFDM. As a whole, the proposed techniques at VLC transmitter can improve the LED non-linearities even for large input signals.

References

    1. 1)
      • 9. Kaur, N., Kansal, L.: ‘Reducing the peak to average power ratio of OFDM signals through Walsh Hadamard transform’, Glob. J. Res. Eng., 2013, 13, (1), pp. 1723.
    2. 2)
      • 2. Chandrasekhar, V., Andrews, J.G., Gatherer, A: ‘Femtocell networks: a survey’, IEEE Commun. Mag., 2008, 46, (9), pp. 5967.
    3. 3)
      • 6. Mesleh, R., Elgala, H., Haas, H.: ‘On the performance of different OFDM based optical wireless communication systems’, IEEE/OSA J. Opt. Commun. Netw., 2011, 3, (8), pp. 620628.
    4. 4)
      • 3. Burchardt, H., Serafimovski, N., Tsonev, D., et al: ‘VLC: beyond point-to-point communication’, IEEE Commun. Mag., 2014, 52, (7), pp. 98105.
    5. 5)
      • 18. Haykin, S.: ‘Adaptive filter theory’ (Prentice-Hall, Englewood Cliffs, NJ, 1996, 3rd edn.).
    6. 6)
      • 12. Asatani, K., Kimura, T.: ‘Linearization of LED nonlinearity by predistortions’, IEEE J. Solid-State Circuits, 1978, 13, (1), pp. 133138.
    7. 7)
      • 11. Elgala, H., Mesleh, R., Haas, H.: ‘Non-linearity effects and predistortion in optical OFDM wireless transmission using LEDs’, Int. J. Ultra Wideband Commun. Syst., 2009, 1, pp. 143150.
    8. 8)
      • 7. Zhang, H., Yuan, Y., Xu, W.: ‘PAPR reduction for DCO-OFDM visible light communications via semidefinite relaxation’, IEEE Photonics Technol. Lett., 2014, 26, (17), pp. 17181721.
    9. 9)
      • 16. Besbes, H., Le-Ngoc, T., Lin, H.: ‘A fast adaptive polynomial predistorter for power amplifiers’. Proc. IEEE Global Telecommunications Conf., July 2001, pp. 659663.
    10. 10)
      • 10. Kazuaki, T., Kishiyama, Y., Tanno, M., et al: ‘Investigation of two-dimensional orthogonal sequence mapping to multi-layer reference signal for LTE-advanced downlink’. Proc. IEEE Vehicular Technology Conf., Fall 2010, pp. 15.
    11. 11)
      • 4. Armstrong, J.: ‘OFDM for optical communications’, J. Lightwave Technol., 2009, 27, (3), pp. 189204.
    12. 12)
      • 15. Muhonen, K.J., Kavehrad, M., Krishnamoorthy, R.: ‘Look-up table techniques for adaptive digital predistortion: a development and comparison’, IEEE Trans. Veh. Technol., 2000, 49, (5), pp. 19952002.
    13. 13)
      • 13. Qian, H., Yao, S.J., Cai, S.Z., et al: ‘Adaptive postdistortion for nonlinear LEDs in visible light communications’, IEEE Photonics J., 2014, 6, (4), pp. 18.
    14. 14)
      • 5. Armstrong, J., Schmidt, B.: ‘Comparison of asymmetrically clipped optical OFDM and DC-biased optical OFDM in AWGN’, IEEE Commun. Lett., 2008, 12, (5), pp. 343345.
    15. 15)
      • 17. Cavers, J.K.: ‘Amplifier linearization using a digital predistorter with fast adaptation and low memory requirements’, IEEE Trans. Veh. Technol., 1990, 39, (11), pp. 374382.
    16. 16)
      • 8. Yu, B., Zhang, H., Wei, L., et al: ‘Subcarrier grouping OFDM for visible-light communication systems’, IEEE Photonics J., 2015, 7, (5), pp. 112.
    17. 17)
      • 1. Rappaport, T., Sun, S., Mayzus, R., et al: ‘Millimeter wave mobile communications for 5G cellular: it will work!’, IEEE Access, 2013, 1, pp. 335349.
    18. 18)
      • 14. Elgala, H., Mesleh, R., Haas, H.: ‘An LED model for intensity-modulated optical communication systems’, IEEE Photon. Technol. Lett., 2010, 22, (11), pp. 835837.
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