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针对相干光正交频分复用(CO-OFDM)系统中光纤信道快变对系统可靠性和有效性的降低,设计了一种符号映射分析(ASM,analysis of symbols mapping)算法,通过对接收到的OFDM符号星座图进行分析,不断地对由信道估计得到的传递函数进行修正,在不需要大量导频的情况下能快速跟踪信道的变化。仿真结果表明:在40Gb/s的快变光纤信道CO-OFDM系统中,信噪比(SNR)为10dB,在误码率(BER)为10-3时ASM算法比常规的迫零估计(ZFE,zero forcing estima-tion)算法需要的导频间隔减小了1/2;在导频间隔为10、BER为10-3时,ASM算法比常规的ZFE算法有约3.5dB的SNR改善。
In order to reduce the reliability and effectiveness of the system, the fiber channel fast variation in Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM) system is designed. An algorithm of symbol mapping analysis (ASM) To the OFDM symbol constellation analysis, constantly on the transfer function obtained by channel estimation correction, in the absence of a large number of pilot cases can quickly track changes in the channel. The simulation results show that the signal-to-noise ratio (SNR) of the 40Gb / s fast-changing optical fiber channel CO-OFDM system is 10dB and the BER of the ASM algorithm is 10dB higher than that of the conventional zero- , zero forcing estimations) reduces the pilot interval required by the algorithm by 1/2; at the pilot interval of 10 and the BER of 10-3, the ASM algorithm has an SNR improvement of about 3.5 dB over the conventional ZFE algorithm.