低压电力线OFDM载波通信系统符号定时同步方法  

Timing Synchronization Methods for Low-voltage OFDM Power Line Communication System

作　　者：罗春风[1] 程时杰[1] 熊兰[1] 文劲宇[1] 张有兵[2] 杨慧敏[1] 

机构地区：[1]华中科技大学电气与电子工程学院,湖北省武汉市430074 [2]浙江大学电气工程学院,浙江省杭州市310027

出　　处：《电力系统自动化》2005年第9期65-71,共7页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(60402009)中华电力教育基金会许继奖教金资助项目。

摘　　要：正交频分复用(OFDM)技术用于低压电力线载波通信可以有效克服电力线弥散信道的多径、频率选择性衰落特性的影响。但OFDM系统对同步误差的影响相当敏感,准确的符号定时和频偏估计是实现OFDM系统的关键。文中采用改进的延迟相关符号定时同步方法实现了低压电力线OFDM载波通信系统的准确符号同步。对比分析了双滑动窗功率比值法、延迟相关算法、改进的延迟相关算法应用于实际低压电力线弥散通信环境中的效果,结果表明采用改进的延迟相关算法更稳定可靠,精度更高。实际低压电力线信道实验网络测试表明,改进的延迟相关算法可以更准确有效地进行OFDM系统符号定时,且符号定时同步不受频偏影响,具有很强的鲁棒性。Orthogonal frequency division multiplexing (OFDM) is considered as an effective method for overcoming the problems of noise pollution, multi path propagation and time varying frequency selective fading in low voltage power line communication (PLC). However, the OFDM system is sensitive to the error of synchronization. Accurate symbol timing and carrier frequency offset are the key factors to the performance of the OFDM based PLC system. In this paper, an improved delay and correlation algorithm is proposed for timing synchronization. The delay and correlation algorithms as well as the double sliding windows power ratio algorithm are used in an actual low voltage power line communication system. The three timing synchronization algorithms are compared in terms of performance. The approach proposed is independent of the frequency offset and robust to the multi path fading channels. It is concluded that the synchronization scheme proposed is effective for OFDM based PLC systems.

关 键 词：低压电力线载波通信 正交频分复用 符号定时同步 延迟相关算法 双滑动窗口法 

分 类 号：TM73[电气工程—电力系统及自动化] TN914.3[电子电信—通信与信息系统]