• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.103-109
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• 2003

We have proposed the 4-Dimensional Multiple-Subcarrier Modulation with fixed bias in Optical Wireless Communications. Here, the 4-D signal vectors are derived from the optimization technique of signal waveforms maximizing the minimum distance between signal points in an n-dimensional Euclidean sphere. The resulting vectors are used in generating the output amplitude of impulse generator in a Multiple-Subcarrier Modulation scheme. We have achieved that the normalized power requirement of the proposed system is maximum 3 dB and 3.3 dB smaller than those of normal QPSK, Reserved Subcarrier, and Minimum Power scheme, respectively. Also, in the range of 1.125 ∼ 1.25 of the normalized bandwidth, the proposed system has maximum 3 dB, 2 ∼ 4 dB, 0 ∼ 3 dB smaller bandwidth requirement compare to normal QPSK, Res. Subcarrier, Min. Power schemes, respectively.