Information Rate of OFDM-Based Optical Wireless Communication Systems With Nonlinear Distortion

In this paper, a piecewise polynomial function is proposed as a generalized model for the nonlinear transfer characteristic of the transmitter for optical wireless communications (OWC). The two general multicarrier modulation formats for OWC based on orthogonal frequency-division multiplexing (OFDM), direct-current-biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM), are studied. The nonlinear distortion of the electrical signal-to-noise ratio (SNR) at the receiver is derived in closed form, and it is verified by means of a Monte Carlo simulation. This flexible and accurate model allows for the application of pre-distortion and linearization of the dynamic range of the transmitter between points of minimum and maximum radiated optical power. Through scaling and DC-biasing the transmitted signal is optimally conditioned in accord with the optical power constraints of the transmitter front-end, i.e., minimum, average and maximum radiated optical power. The mutual information of the optimized optical OFDM (O-OFDM) schemes is presented as a measure of the capacity of these OWC systems under an average electrical power constraint. When the additional DC bias power is neglected, DCO-OFDM is shown to achieve the Shannon capacity when the optimization is employed, while ACO-OFDM exhibits a 3-dB gap which grows with higher information rate targets. When the DC bias power is counted towards the signal power, DCO-OFDM outperforms ACO-OFDM for the majority of average optical power levels with the increase of the information rate target or the dynamic range. The results can be considered as a lower bound on the O-OFDM system capacity.

[1]  Julian J. Bussgang,et al.  Crosscorrelation functions of amplitude-distorted gaussian signals , 1952 .

[2]  C.E. Shannon,et al.  Communication in the Presence of Noise , 1949, Proceedings of the IRE.

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

[4]  J. Rice.  Mathematical Statistics and Data Analysis , 1988 .

[5]  R.J. Green,et al.  Bit-error-rate performance of lightwave hybrid AM/OFDM systems with comparison with AM/QAM systems in the presence of clipping impulse noise , 1996, IEEE Photonics Technology Letters.

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

[7]  C. Shannon,et al.  Communication In The Presence Of Noise , 1998, Proceedings of the IEEE.

[8]  G. David Forney,et al.  Modulation and Coding for Linear Gaussian Channels , 1998, IEEE Trans. Inf. Theory.

[9]  Gordon L. Stüber,et al.  Clipping noise mitigation for OFDM by decision-aided reconstruction , 1999, IEEE Communications Letters.

[10]  J. Campello.  Practical bit loading for DMT , 1999, 1999 IEEE International Conference on Communications (Cat. No. 99CH36311).

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

[12]  Howard E. Levin.  A complete and optimal data allocation method for practical discrete multitone systems , 2001, GLOBECOM'01. IEEE Global Telecommunications Conference (Cat. No.01CH37270).

[13]  Joseph M. Kahn,et al.  Upper-bounding the capacity of optical IM/DD Channels with multiple-subcarrier modulation and fixed bias using trigonometric moment space method , 2002, IEEE Trans. Inf. Theory.

[14]  Hideki Ochiai,et al.  Performance analysis of deliberately clipped OFDM signals , 2002, IEEE Trans. Commun..

[15]  Jeffrey B. Carruthers,et al.  Wireless infrared communications , 2003, Proc. IEEE.

[16]  Alexander M. Haimovich,et al.  Iterative estimation and cancellation of clipping noise for OFDM signals , 2003, IEEE Communications Letters.

[17]  John M. Cioffi,et al.  Maximum-likelihood detection of nonlinearly distorted multicarrier symbols by iterative decoding , 2003, IEEE Trans. Commun..

[18]  Frank R. Kschischang,et al.  Capacity bounds for power- and band-limited optical intensity channels corrupted by Gaussian noise , 2004, IEEE Transactions on Information Theory.

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

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

[21]  Sang Joon Kim,et al.  A Mathematical Theory of Communication , 2006 .

[22]  Harald Haas,et al.  OFDM Visible Light Wireless Communication Based on White LEDs , 2007, 2007 IEEE 65th Vehicular Technology Conference - VTC2007-Spring.

[23]  Xia Li,et al.  Channel Capacity of IM/DD Optical Communication Systems and of ACO-OFDM , 2007, 2007 IEEE International Conference on Communications.

[24]  Holger Claussen.  Performance of Macro- and Co-Channel Femtocells in a Hierarchical Cell Structure , 2007, 2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications.

[25]  Jian Li,et al.  Exact BEP Analysis for Coherent M-ary PAM and QAM over AWGN and Rayleigh Fading Channels , 2008, VTC Spring 2008 - IEEE Vehicular Technology Conference.

[26]  Steve Hranilovic,et al.  Capacity of Optical Intensity Channels with Peak and Average Power Constraints , 2009, 2009 IEEE International Conference on Communications.

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

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

[29]  Sebastian Randel,et al.  Advanced Modulation Schemes for Short-Range Optical Communications , 2010, IEEE Journal of Selected Topics in Quantum Electronics.

[30]  K. Langer,et al.  513 Mbit/s Visible Light Communications Link Based on DMT-Modulation of a White LED , 2010, Journal of Lightwave Technology.

[31]  P. Winzer,et al.  Capacity Limits of Optical Fiber Networks , 2010, Journal of Lightwave Technology.

[32]  Steve Hranilovic,et al.  Capacity Bounds for Wireless Optical Intensity Channels With Gaussian Noise , 2010, IEEE Transactions on Information Theory.

[33]  S. Dimitrov,et al.  Signal Shaping and Modulation for Optical Wireless Communication , 2012, Journal of Lightwave Technology.

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

[35]  Svilen Dimitrov,et al.  Optimum Signal Shaping in OFDM-Based Optical Wireless Communication Systems , 2012, 2012 IEEE Vehicular Technology Conference (VTC Fall).

[36]  Xia Li,et al.  On the Capacity of Intensity-Modulated Direct-Detection Systems and the Information Rate of ACO-OFDM for Indoor Optical Wireless Applications , 2012, IEEE Transactions on Communications.

[37]  Dov Wulich,et al.  On Achievable Rate of Multicarrier with Practical High Power Amplifier , 2012, EW.