CO-OFDM系统不同调制方式的性能分析

Performance analysis of different modulation schemes for coherent optical OFDM system

在没有色散补偿的情况下,对不同调制方式的相干光正交频分复用(CO-OFDM)系统的性能进行研究。结果表明:2PSK抗误码性能较好,频带利用率较低;4QAM频带利用率是2PSK的两倍,当系统误码率在10-3以内时,所需OSNR约为9dB;8QAM频带利用率比前两者高,但抗误码性能较前两者差。因此,设计通信系统时,要根据系统的实际要求来选择具体的调制方式。

Without optical dispersion compensation,the performances of different modulation schemes for coherent optical orthogonal frequency division multiplexing（CO-OFDM） system are analyzed.The simulation results show that the anti-BER ability of 2PSK is best,but its bandwidth efficiency is lower than other modulation methods.The bandwidth efficiency of 4QAM is as twice as the 2PSK,and the required OSNR is about 9dB when the BER of the system is smaller than 10-3.Although the bandwidth efficiency of 8QAM is higher than other two kinds of modulation methods,its performance of anti-BER is relatively poor.Therefore,the specific modulation scheme should be chosen depending on the actual needs of the system.