Experimental demonstration of high spectral efficiency SC‐FDMA with soft clipping for optical wireless communication systems

Abstract

To the best of the authors’ knowledge, this study is the first to combine two single-carrier frequency-division multiple accesses (SC-FDMAs) with soft clipping for optical wireless communication systems. By combining two SC-FDMAs, the spectral efficiency is increased. A simple, low-cost implementation is considered. A 50 mW blue laser with a wavelength of 405 nm is used in this experiment. The optimum driving voltage is 5.25 V. In situations in which only real components can be employed, intensity modulation/direct detection is adopted. From the experimental results, 128-QAM (quadrature amplitude modulation) is perfectly employed, and because of the avalanche photodiode, a bandwidth of only 100 MHz is used. As a result, a total speed of 261.1 Mbps can be achieved. By mixing the SC-FDMA with soft clipping of 3 dB, a peak-to-average power ratio reduction of 6 dB can be achieved with no bit-error rate performance degradation.