Joint IQ imbalance compensation and channel estimation in coherent optical OFDM systems
Joint IQ imbalance compensation and channel estimation in coherent optical OFDM systems
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DOI：
10.1109/icspcs.2016.7843310
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发表时间：
2016-12
期刊：
影响因子：
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通讯作者：
Xiaojie Wang;Benedikt Leible;Wenhao Wang;D. Rorich;S. Brink
中科院分区：
文献类型：
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作者：
Xiaojie Wang;Benedikt Leible;Wenhao Wang;D. Rorich;S. Brink
相干光正交频分复用（CO-OFDM）技术被认为是满足数据传输速率要求的最有前途的技术。它具有相干检测和OFDM的许多优点，使光纤上的光传输对色散和偏振模色散等失真非常鲁棒。然而，CO-OFDM对IQ不平衡敏感，特别是当使用零差（或直接下变频）接收器时。在本文中，我们研究了发送端和接收端IQ不平衡对单模光纤上相干光传输的影响。此外，我们研究了不同的方法，特别是在频域中，联合补偿IQ不平衡和均衡光纤信道，考虑到色散的影响。提出的最小均方误差（MMSE）补偿算法表现出上级性能，与传统的方法相比。此外，最佳设计的训练序列推导和表达在一个封闭的形式，它提供了显着的性能增益，即使没有应用IQ不平衡补偿。
Coherent optical orthogonal frequency division multiplexing (CO-OFDM) is considered to be promising technique for meeting the ever increasing demand of data rate. It exhibits many advantages of coherent detection and OFDM, making the optical transmission over fiber extremely robust against distortions such as chromatic dispersion and polarisation mode dispersion. However, CO-OFDM is sensitive to IQ imbalance, in particular, when a homodyne (or direct down-conversion) receiver is used. In this paper, we study the impact of transmitter and receiver side IQ imbalance on coherent optical transmission over a single-mode fiber. Moreover, we investigate different methods, particularly in the frequency domain, to jointly compensate the IQ imbalance and to equalize the optical fiber channel, taking the effect of chromatic dispersion into account. The proposed minimum mean square error (MMSE) compensation algorithm shows superior performance, compared to conventional method. Furthermore, an optimum design of training sequence is derived and expressed in a closed-form, which provides significant performance gains even without applying IQ imbalance compensation.