基于DCO-OFDM的帧内信号时域调整技术研究(英文)

Analysis of Time Domain Reshuffling Based on DC-biased Optical OFDM

在传统OFDM系统中,OFDM码元在信道特性不佳时可能会超出保护间隔并严重影响相邻码元,从而造成码间干扰和载波间干扰.针对此类干扰,在高速非相干光OFDM通信系统中,提出了一种基于直流偏置光OFDM的帧内信号时域调整方案.该方案运用傅里叶变换的基本性质,通过简单的频域子信道预处理,便可以将直流偏置光OFDM时域信号进行帧内交叉性时序搬移,使信号能量从码元边缘部分集中到中间部分.数值模拟表明,该方案能显著降低因码元超出保护间隔而引起的码间干扰和载波间干扰,从而有效改善系统的误码率性能.对于某些通过减小保护间隔来提高信息传输有效性的光OFDM系统,该方案也具有很大意义.

In conventional OFDM system, an OFDM symbol will exceeds its guard interval （GI） and seriously interfere with its neighboring symbols when channel characteristic is unsatisfactory. This will cause inter-symbol interference （ISI） and inter-carrier interference （ICI）. In high-speed incoherent optical OFDM communication system, a novel time domain reshuffling method for mitigating ISI and ICI based on DCO-OFDM was proposed. This scheme utilized the properties of Fourier Transform. By simple pre- processing subcarrier channels in frequncy domain, sampling sequence of a DCO-OFDM symbol in time domain was exchanged interactively. Thus signal energy was centralized in the central part of a symbol. Numerical simulation indicates that ISI and ICI is significantly reduced and system BER performance is improved effectively due to signal surpassing the GI. In optical OFDM systems with insufficient GI for the popurse of higher information transmission efficiency,the reshuffling scheme also has a great value.