介绍了光纤射频传输(Radio over Fiber,RoF)系统中相干正交频分复用(CO—OFDM)的原理和发展现状,并对主流的基于直接调制结构和上下变频结构的CO-OFDM方案进行了论述,分析比较了不同方案的优缺点。此外还对一些基于相干解调的改进方案进行了研究,包括相位噪声补偿和自载波提取,从而有效地改善了系统性能,降低了系统成本。
The principle and the development about CO-OFDM in RoF system are introduced simply. Then we discuss the existing coherent OFDM schemes, including direct modulation structure and frequency conversion structure, the advantages and disadvantages of each other are also compared. We especially focus on some modified method, such as phase noise compensation and self carrier extraction, which could improve the system performance and reduce the cost effectively.