基于超混沌系统的正交频分复用时频同步算法  

Time and Frequency Synchronization Algorithm Using Hyperchaotic System for OFDM Systems

作　　者：唐良瑞[1] 左琪[1] 

机构地区：[1]华北电力大学电气与电子工程学院,北京市昌平区102206

出　　处：《中国电机工程学报》2010年第12期122-128,共7页Proceedings of the CSEE

基　　金：国家自然科学基金项目(60402004)~~

摘　　要：针对低压电力线信道噪声干扰强、多径衰落严重,而传统同步算法保密性弱、小数倍载波频偏估计易受多径衰落影响的缺点,提出一种适合于低压电力线通信信道的正交频分复用(orthogonal frequency division multiplexing,OFDM)时频同步算法。将超混沌系统生成的混沌序列用于构造同步训练序列,提出新的定时偏差估计和小数倍频偏估计的算法,在延续循环移位的思想的基础上完成整数倍频偏估计。理论分析表明,混沌系统对初始值的敏感性与所提出的算法相结合,可极大地增强系统的保密性。仿真结果表明,所提出的定时偏差估计准确率高、频偏估计性能更优,能有效地对抗低压电力线通信信道的强噪声和多径衰落。As the low-voltage power line channel suffers serious noise interference and multipath fading, and the traditional synchronization algorithm has the disadvantages of weak security and decimal carder frequency offset estimation is sensitive to multipath fading, a time and frequency orthogonal frequency division multiplexing （OFDM） synchronization algorithm applicable to the low-voltage power line communication was introduced. The sequences generated by hyperchaotic system was used to construct the synchronization training sequences first, then, a new timing error estimation and decimal carrier frequency offset estimation was presented, the integer cartier frequency offset estimation was completed based on the cycle shift last. Theoretical analysis demonstrates that the combination of the sensitivity of chaotic system to initial condition and the proposed algorithm profoundly enhances the security of the OFDM system. Simulation results show the high-accuracy of the timing offset estimation and excellent performance of the frequency offset estimation, and the effective opposability to the strong noise and serious multipath fading.

关 键 词：正交频分复用系统 低压电力线 定时偏差估计:频偏估计 超混沌系统 保密性 

分 类 号：TM73[电气工程—电力系统及自动化]