Robust Frequency Offset Estimation for Coherent DSCM Systems Under Severe Bandwidth Limitation

作     者：Jin, Yongchao Yang, Yanfu Xiang, Qian Gong, Siyu Cheng, Chen Fan, Linsheng Zuo, Tianjian 

作者机构：Harbin Inst Technol Dept Elect & Informat Engn Shenzhen 518055 Peoples R China Huawei Technol Co Ltd Network Technol Lab Shenzhen 518129 Peoples R China 

出 版 物：《IEEE PHOTONICS TECHNOLOGY LETTERS》 (IEEE Photonics Technol Lett)

年 卷 期：2025年第37卷第14期

页      面：769-772页

核心收录：

学科分类：0808[工学-电气工程] 08[工学] 0702[理学-物理学] 

基　　金：Guangdong Basic and Applied Basic Research Foundation [2025A1515010277] Shenzhen Municipal Science and Technology Innovation Council [JCYJ20240813104835048] 

主　　题：Bandwidth Adders Signal to noise ratio Frequency estimation Frequency division multiplexing Accuracy Optical transmitters Optical receivers Optical fiber dispersion Frequency-domain analysis Frequency offset estimation digital subcarrier multiplexing coherent communications 

摘      要：Since digital subcarrier multiplexing (DSCM) signals require frequency offset estimation (FOE) and compensation before demultiplexing, we propose a robust FOE scheme for DSCM systems that estimates the frequency offset (FO) by calculating the magnitude sum of spectral components within a specified range centered at zero frequency. The scheme remains effective even under severe bandwidth limitation conditions. The experimental results show that with FFT sizes of 2048, the maximum FOE errors are 119 MHz, 123 MHz, and 87MHz for the 4, 6, and 8 subcarrier DSCM signals, respectively. Additionally, the cumulative distribution functions (CDF) of the FOE error less than 50 MHz are 0.79, 0.81, and 0.82, respectively. Furthermore, the proposed scheme demonstrates stable performance across a wide range of FO and received optical power (ROP). Therefore, the proposed scheme can achieve high FOE accuracy in the presence of severe bandwidth limitation for coherent DSCM systems.