利用循环前缀的OFDM系统定时同步算法

doi:10.3969/j.issn.1001-2400.2013.01.025

J4 ›› 2013, Vol. 40 ›› Issue (1): 141-147.doi: 10.3969/j.issn.1001-2400.2013.01.025

利用循环前缀的OFDM系统定时同步算法

汪涵^1,2;朱磊基^1,2;施玉松¹;邢涛¹;王营冠¹

(1. 中国科学院上海微系统与信息技术研究所无线传感网与通信重点实验室，上海 200050；
2. 中国科学院研究生院，北京 100049)

收稿日期:2011-09-13 出版日期:2013-02-20 发布日期:2013-03-28
通讯作者: 汪涵
作者简介:汪涵(1986-)，男，中国科学院上海微系统与信息技术研究所博士研究生，E-mail：wanghan_115@163.com．
基金资助:
国家重大专项03专项资助项目(2010ZX03006-002);上海市科委攻关资助项目(10511502500)

Novel time synchronization algorithm using the cyclic prefix for OFDM systems

WANG Han^1,2;ZHU Leiji^1,2;SHI Yusong¹;XING Tao¹;WANG Yingguan¹

(1. Key Lab. of Wireless Sensor Network ＆ Communication, Shanghai Inst. of Microsystem and Info. Tech., Chinese Academy of Sci., Shanghai 200050， China;
2. Graduate Univ. of Chinese Academy of Sci., Beijing 100049， China)

Received:2011-09-13 Online:2013-02-20 Published:2013-03-28
Contact: WANG Han

摘要/Abstract

摘要：

在频率选择性衰落信道下，由于符号间干扰(ISI)的存在，利用循环前缀(CP)的最大似然正交频分复用(OFDM)系统同步算法性能较差．首先，通过改善循环前缀“集相关”特性存在的缺陷，提出了一种新的定时度量函数．利用无符号间干扰区间内的采样点，对相隔OFDM符号长度的两个数据块进行相关运算．其次，提出新的检测函数，在由定时度量函数最大值和循环前缀长度确定的区间内，搜索检测函数的最大值，得到定时偏移估计值，完成定时同步．仿真结果表明，在频率选择性衰落信道下，与已有算法相比，本算法定时偏移估计值期望更接近理想值，均方差更小，复杂度更低．

关键词: 频率选择性衰落, 符号间干扰, 循环前缀, 正交频分复用, 集相关, 定时同步

Abstract:

Due to the intersymbol interference (ISI), the Maximum Likelihood (ML) algorithm using the cyclic prefix (CP) in orthogonal frequency division multiplexing (OFDM) systems performs poorly in frequency selective fading channels. Firstly, a novel timing metric is presented, which avoids the disadvantage of ensemble correlation. Using the sample data that is not affected by the ISI, the novel algorithm performs correlation operations between two data blocks which are a distance of an OFDM symbol length apart from each other. Secondly, we propose a novel detection function. By searching its maximum in a search range decided by the maximum of the timing metric and the length of CP, the timing offset is gained and the time synchronization can be obtained. Simulation results show that the novel algorithm has more accurate time offset estimation, smaller Mean Square Error (MSE) and lower complexity in frequency selective fading channels.

Key words: frequency selective fading, intersymbol interference, cyclic prefix, orthogonal frequency division multiplexing, ensemble correlation, time synchronization

中图分类号:

TN92

汪涵;朱磊基;施玉松;邢涛;王营冠. 利用循环前缀的OFDM系统定时同步算法[J]. J4, 2013, 40(1): 141-147.

WANG Han;ZHU Leiji;SHI Yusong;XING Tao;WANG Yingguan. Novel time synchronization algorithm using the cyclic prefix for OFDM systems[J]. J4, 2013, 40(1): 141-147.

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利用循环前缀的OFDM系统定时同步算法

Novel time synchronization algorithm using the cyclic prefix for OFDM systems

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