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A full-duplex optical access system with hybrid 64/16/4QAM-OFDM downlink 被引量:2
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作者 贺超 谭泽富 +5 位作者 邵宇丰 蔡黎 蒲鹤升 朱云乐 黄思斯 刘毓 《Optoelectronics Letters》 EI 2016年第5期361-365,共5页
A full-duplex optical passive access scheme is proposed and verified by simulation, in which hybrid 64/16/4-quadrature amplitude modulation(64/16/4QAM) orthogonal frequency division multiplexing(OFDM) optical signal i... A full-duplex optical passive access scheme is proposed and verified by simulation, in which hybrid 64/16/4-quadrature amplitude modulation(64/16/4QAM) orthogonal frequency division multiplexing(OFDM) optical signal is for downstream transmission and non-return-to-zero(NRZ) optical signal is for upstream transmission. In view of the transmitting and receiving process for downlink optical signal, in-phase/quadrature-phase(I/Q) modulation based on Mach-Zehnder modulator(MZM) and homodyne coherent detection technology are employed, respectively. The simulation results show that the bit error ratio(BER) less than hardware decision forward error correction(HD-FEC) threshold is successfully obtained over transmission path with 20-km-long standard single mode fiber(SSMF) for hybrid downlink modulation OFDM optical signal. In addition, by dividing the system bandwidth into several subchannels consisting of some continuous subcarriers, it is convenient for users to select different channels depending on requirements of communication. 展开更多
关键词 downlink duplex multiplexing quadrature transmitting modulator bandwidth correction transmitter hardware
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Performance of a PPM hard decision-based ARQ-FSO system in a weak turbulence channel
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作者 尹建军 刘宏展 +2 位作者 黄蓉 高争光 韦中超 《Chinese Optics Letters》 SCIE EI CAS CSCD 2017年第6期1-6,共6页
We present an automatic repeat request(ARQ) free space optical(FSO) system, which consists of a pulse position modulation(PPM) hard decision and an ARQ. The new ARQ's data error detection is based on a PPM hard... We present an automatic repeat request(ARQ) free space optical(FSO) system, which consists of a pulse position modulation(PPM) hard decision and an ARQ. The new ARQ's data error detection is based on a PPM hard decision's results and can eliminate the traditional ARQ information redundancy. The results of the numerical simulation have a good agreement with theoretical analysis and show that the ARQ-FSO system can effectively improve the bit error rate(BER) performance of the direct hard decision PPM system. Additionally, the proposed system significantly improves the average throughput efficiency compared to traditional ARQ systems.These characteristics make the ARQ-FSO system suitable for application in low BER and complexity FSO scenarios. 展开更多
关键词 turbulence throughput redundancy eliminate request scenarios transmitter symbol decoding correction
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