摘要
研究了基于光梳状波的正交频分复用-无源光网(OFDM-PON)下行相干检测实验系统的结构和数字信号处理算法,采用多波长的光梳状波发生器作为光线路终端光源,其中一个波长作为传输OFDM信号的信号光,相邻的光波长作为本振光。基于该系统,光网络单元端的相干接收可以实现光相位噪声抵消。由于没有载波偏移和光相位噪声,数字信号处理过程被简化。比较了导频辅助(PA)算法、最大似然(ML)算法和PA+ML算法3种相位估计算法的性能。研究结果表明,PA+ML算法能获得更好的性能,可以将导频子载波的数目减少至2,并且接收机灵敏度可提高至-30dBm。该OFDM-PON系统的硬件和软件设计有望成为下一代光接入网络的解决方案。
A structure and a digital signal processing algorithm of orthogonal frequency division multiplexing-passive optical network（OFDM-PON）downstream coherent detection system based on optical-comb wave are studied.A multi-wavelength optical-comb wave generator is used as the source of optical line terminal.One of the wavelengths is used as OFDM signal carrier and its adjacent wavelength is used as local oscillation light.In this way,the optical phase noise cancellation is achieved in coherent reception at optical network unit.Since the carrier offset and optical phase noise are avoided,the digital signal processing can be simplified.The comparison of the performance of three phase estimation algorithms,which are pilot aided（PA）algorithm,maximum likelihood（ML）algorithm and PA＋ML algorithm,are carried out.It is found that the performance of the PA＋ML algorithm is far more better.It can reduce the number of pilot subcarriers to 2and the receiver sensitivity can be improved to-30 dBm.The hardware and software designs of the OFDM-PON system are expected to be a promise solution for the next generation optical access networks.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2017年第7期58-66,共9页
Acta Optica Sinica
基金
国家自然科学基金国际合作项目(61420106011)
国家自然科学基金(61132004
61275073)
上海市科委项目(16511104100
16YF1403900
15511105400
15530500600)
关键词
光通信
正交频分复用
光梳状波
同相正交调制器
相干接收机
导频
最大似然估计
optical communications
orthogonal frequency division multiplexing-passive optical network
optical-comb wave
in-phase quadrature modulator
coherent receiver
pilot
maximum likelihood estimation
