Optimum Signal Shaping in OFDM-Based Optical Wireless Communication Systems

In this paper, a framework for optimum signal shaping in multi-carrier modulation is presented for optical wireless communications (OWC). The two fundamental multi-carrier transmission schemes based on orthogonal frequency division multiplexing (OFDM), direct-current-biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM), are studied. The optimum signal shaping is defined as optimum biasing and optimum scaling of the time domain signal within the optical power constraints of the transmitter front-end. These include the boundaries of the limited linear dynamic range, such as minimum and maximum radiated optical power, and the desired average optical power level. As a result, the minimum required electrical signal-to-noise ratio (SNR) to maintain a target bit-error ratio (BER) is obtained for a desired multi-level quadrature amplitude modulation (M-QAM) scheme and a given combination of optical power constraints. The average optical power is varied over dynamic ranges of 10 dB, 20 dB and 30 dB. With the increase of the dynamic range and for a major portion of the average optical power levels, DCO-OFDM demonstrates a lower minimum electrical SNR requirement for a target BER as compared to ACO-OFDM for modulation orders with similar spectral efficiencies.

[1]  Jean Armstrong,et al.  Power efficient optical OFDM , 2006 .

[2]  G. Sarychev,et al.  Prophylactic UV Radiation and CIE Standard on Photobiological Safety of Lamps and Lamp Systems , 2004 .

[3]  David Tse,et al.  Fundamentals of Wireless Communication , 2005 .

[4]  Svilen Dimitrov,et al.  Clipping Noise in OFDM-Based Optical Wireless Communication Systems , 2012, IEEE Transactions on Communications.

[5]  Peter Grant,et al.  DIGITAL COMMUNICATIONS , 2022 .

[6]  Davide Dardari,et al.  A theoretical characterization of nonlinear distortion effects in OFDM systems , 2000, IEEE Trans. Commun..

[7]  Joseph M. Kahn,et al.  Wireless Infrared Communications , 1994 .

[8]  J.E. Mazo,et al.  Digital communications , 1985, Proceedings of the IEEE.

[9]  H. Haas,et al.  Practical considerations for indoor wireless optical system implementation using OFDM , 2009, 2009 10th International Conference on Telecommunications.

[10]  Masao Nakagawa,et al.  Indoor visible communication utilizing plural white LEDs as lighting , 2001, 12th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications. PIMRC 2001. Proceedings (Cat. No.01TH8598).

[11]  Harald Haas,et al.  Non-linearity effects and predistortion in optical OFDM wireless transmission using LEDs , 2009, Int. J. Ultra Wideband Commun. Syst..

[12]  P. M. Grant,et al.  Digital communications. 3rd ed , 2009 .

[13]  Svilen Dimitrov,et al.  On the SIR of a cellular infrared optical wireless system for an aircraft , 2009, IEEE Journal on Selected Areas in Communications.

[14]  Joseph M. Kahn,et al.  Multiple-Subcarrier Modulation for Nondirected Wireless Infrared Communication , 1994, IEEE J. Sel. Areas Commun..