相干光通信实时信号处理

[摘要] 实时单载波相干光通信和实时相干光正交频分复用（OFDM）通信在处理方法和处理顺序上有所不同。实时相干光OFDM通信，接收端的信号处理首先在时域上进行，在时间同步之后便进行频偏估计，随后通过FFT变换之后转换到频域上再进行信道估计、相位噪声估计以及最终的信号检测；实时单载波相干光接收端的信号处理过程在时域上进行，首先进行的是信道估计，随后进行频偏估计。

[关键词] 相干光通信系统；实时数字信号处理技术；单载波技术；频域正交复用技术

[Abstract] The processing method and digital signal processing (DSP) order are different for coherent OFDM modulated systems and coherent-signal carrier systems. In the former, the received signal is first processed in time domain, time is synchronized, and frequency offset compensation is done. Fast Fourier Transform (FFT) changing is then done, and channel estimation, phase noise compensation, and final signal detection are done in the frequency domain. In contrast, DSP for a signal-carrier modulated system is commonly realized in the time domain, and frequency offset compensation follows channel estimation.

[Keywords] coherent optical transmission system; real-time digital signal processing; single carrier; orthogonal frequency division multiplexing