摘要
分析了直接检测光OFDM(DDO-OFDM)传输系统中由数模转换器和光纤链路中的光纤色散所致的OFDM信号高频衰减现象,以及经光纤传输后在光电检测时存在的子载波间互拍干扰现象。提出使用级联变系数训练序列和预增强结构的光OFDM(O-OFDM)信号来降低传输系统所受到的影响。理论分析和实验验证表明,级联变系数训练序列和预增强结构的基带OFDM信号在DDO-OFDM传输系统中,接收灵敏度比常规的交叉型训练序列结构的OFDM信号要高。说明基于级联变系数训练序列和预增强结构的O-OFDM信号的传输性能在抵抗子载波间互拍干扰(SSMI)和频率选择性衰减(FF)方面要优于常规的交叉型训练序列结构的O-OFDM信号。
Frequency selective fading (FF) caused by digital to analog converter and optical fiber dispersion in optical fiber link was analysed, and signal-signal mixing interference (SSMI) when the orthogonal frequency division multiplex- ing (OFDM) signal was detected by PIN after transmitting over the fiber in direct-detection optical OFDM system. The cascaded variable coefficient training sequences and pre-emphasized configuration of O-OFDM signal were proposed to decrease the influence of the SSMI and FF. The theoretical analysis and experimental results show that the receiving sen- sitivity of the cascaded variable coefficient training sequences and pre-emphasized configuration of OFDM signal is higher than the interleaved configuration of training sequence of OFDM signal in DDO-OFDM system. It is demon- strated that the fiber transmission performance of the cascaded variable coefficient training sequences and pre-emphasized configuration of O-OFDM signal is better than the interleaved configuration of training sequence of OFDM signal in robust tolerance against SSMI and FF.
出处
《通信学报》
EI
CSCD
北大核心
2013年第12期149-157,共9页
Journal on Communications
基金
国家自然科学基金资助项目(60977049)
国家高技术研究发展计划("863"计划)基金资助项目(2011AA010203)
湖南省自然科学基金资助项目(12JJ3070)~~
关键词
光正交频分复用
变系数训练序列
预增强
子载波间互拍干扰
频率选择性衰减
光传输
optical orthogonal frequency division multiplexing(O-OFDM)
variable coefficient training sequence
pre-emphasis technique
subcarrier-subcarrier mixing interference(SSMI)
frequency selective fading(FF)
optical trans-mission