Robust and Low-Complexity Principal Component-Based Phase Estimation Algorithm for Probabilistically Shaped Square-QAM Systems
Robust and Low-Complexity Principal Component-Based Phase Estimation Algorithm for Probabilistically Shaped Square-QAM Systems
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DOI：
10.1109/jlt.2020.3010635
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发表时间：
2020-11
影响因子：
4.7
通讯作者：
Xishuo Wang;Qi Zhang;X. Xin;Ran Gao;Kai Lv;Qinghua Tian;Feng Tian;Chuxuan Wang;Xiaolong Pan;Yongjun Wang;Leijing Yang
中科院分区：
文献类型：
--
作者：
Xishuo Wang;Qi Zhang;X. Xin;Ran Gao;Kai Lv;Qinghua Tian;Feng Tian;Chuxuan Wang;Xiaolong Pan;Yongjun Wang;Leijing Yang
针对概率整形 (PS) 方正交幅度调制 (QAM) 系统提出了一种优化的基于主成分的相位估计 (OPCPE) 算法。优化方法基于镜像和部分缩放接收到的星座。数值仿真验证表明，所提出的相位恢复算法在低信噪比（SNR）下优于著名的盲相位搜索（BPS）算法，并解决了高信噪比下基于主成分的相位估计（PCPE）与PS之间的不兼容问题。值得一提的是，该算法保留了PCPE低周跳率（CSR）和低计算复杂度的优点。此外，还研究了结合所提出的算法和 BPS 的混合实现的性能。当PS-64QAM系统的整形参数为0.03时，通过使用所提出的简单和混合方法，达到0.8归一化广义互信息（NGMI）阈值所需的SNR可以分别降低约0.74 dB和0.98 dB，与广泛使用的两级BPS（2S-BPS）算法相当。据我们所知，这是首次将 PCPE 算法鲁棒地应用于 PS 系统，并且所提出的设计具有稳定的 GMI 性能、较强的周滑容限和较低的计算复杂度，这使其成为实际概率形状传输的合适候选者。
An optimized principal component-based phase estimation (OPCPE) algorithm is proposed for probabilistically shaped (PS) square-quadrature amplitude modulation (QAM) systems. The optimization method is based on mirroring and partially scaling the received constellation. Numerical simulation validation shows that the proposed phase recovery algorithm outperforms the well-known blind phase search (BPS) algorithm at low signal-to-noise ratio (SNR) and solves the incompatibility between principal component-based phase estimation (PCPE) and PS at high SNR. It's worth mentioning that the proposed algorithm retains the advantages of low cycle slip rate (CSR) and low computational complexity of PCPE. Furthermore, the performance of a hybrid implementation combining the proposed algorithm and BPS is also investigated. When the shaping parameter for a PS-64QAM system is 0.03, by using the proposed simple and hybrid methods, the SNR required to reach the 0.8 normalized generalized mutual information (NGMI) threshold can be reduced by about 0.74 dB and 0.98 dB, respectively, benchmarking the widely used two-stage BPS (2S-BPS) algorithm. To the best of our knowledge, this is the first time to robustly apply PCPE algorithm to PS systems, and the proposed design has stable GMI performance, strong cycle slip tolerance and low computational complexity, which makes it a suitable candidate for practical probabilistically-shaped transmissions.