摘要
We propose a layered asymmetrically clipped optical fast orthogonal frequency division multiplexing(ACO-FOFDM)scheme for intensitymodulated and directdetected(IM/DD)systems. Layered ACO-FOFDM can compensate the weaknessof conventional ACO-FOFDM in low spectral efficiency. For FOFDM system, the utilization of discrete cosine transform(DCT) instead of fast Fourier transform(FFT) can reduce thecomputational complexity without any influence on bit errorrate(BER) performance. At transmitter, the superposition ofmultiple layers is performed in frequency domain, and the iterative receiver is used to recover transmitted signals by subtracting the clipping noise of each layer. We compare theBER performance of the proposed layered ACO-FOFDM system and DC-offset FOFDM(DCO-FOFDM) system with optimal DCbias at the same spectral efficiency. Simulation results show that in terms of optical bit energy to noise powerratio, the layered ACO-OFDM system has 1.23 dB, 2.77 dB,3.67 dB and 0.78 dB improvement at the forward error correction(FEC) limit compared with DCO-FOFDM system whenthe spectral efficiencies are 1 bit/s/Hz, 2 bits/s/Hz, 3 bits/s/Hz and 4 bits/s/Hz. The layered ACO-FOFDM system with zero DC-bias is more suitable for adaptive system, so this system also has potential for application in IM/DD systems.
We propose a layered asymmetrically clipped optical fast orthogonal frequency division multiplexing(ACO-FOFDM)scheme for intensitymodulated and directdetected(IM/DD)systems. Layered ACO-FOFDM can compensate the weaknessof conventional ACO-FOFDM in low spectral efficiency. For FOFDM system, the utilization of discrete cosine transform(DCT) instead of fast Fourier transform(FFT) can reduce thecomputational complexity without any influence on bit errorrate(BER) performance. At transmitter, the superposition ofmultiple layers is performed in frequency domain, and the iterative receiver is used to recover transmitted signals by subtracting the clipping noise of each layer. We compare theBER performance of the proposed layered ACO-FOFDM system and DC-offset FOFDM(DCO-FOFDM) system with optimal DCbias at the same spectral efficiency. Simulation results show that in terms of optical bit energy to noise powerratio, the layered ACO-OFDM system has 1.23 dB, 2.77 dB,3.67 dB and 0.78 dB improvement at the forward error correction(FEC) limit compared with DCO-FOFDM system whenthe spectral efficiencies are 1 bit/s/Hz, 2 bits/s/Hz, 3 bits/s/Hz and 4 bits/s/Hz. The layered ACO-FOFDM system with zero DC-bias is more suitable for adaptive system, so this system also has potential for application in IM/DD systems.
基金
supported in part by National Natural Science Foundation of China under Grant Nos.61427813 and 61331010
in part by ZTE Industry-Academia-Research Cooperation Funds
