华东师范大学学报(自然科学版)

• 物理学 • 上一篇    下一篇

OFDM软件无线电接收机的采样时钟同步

谢 颖[1], 胡星波[1], 许炜阳[2]   

  1. 1. 华东师范大学 信息科学技术学院, 上海 200241;
    2. 重庆大学 通信工程学院, 重庆 400044
  • 收稿日期:2015-08-26 出版日期:2016-11-25 发布日期:2017-01-13
  • 通讯作者: 胡星波, 男, 博士, 讲师, 研究方向为无线通信与网络. E-mail: xbhu@ee.ecnu.edu.cn.
  • 基金资助:

    粮食公益性行业科研专项(201313009);
    国家自然科学基金(61201177)

Sampling clock synchronization for OFDM based software-defined radio receivers

XIE Ying[1], HU Xing-bo[1], XU Wei-yang[2]   

  1. 1. School of Information Science and Technology, East China Normal University, Shanghai 200241, China;
    2. College of Communication Engineering, Chongqing University, Chongqing 400044, China
  • Received:2015-08-26 Online:2016-11-25 Published:2017-01-13

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摘要：

针对正交频分复用(Orthogonal Frequency Division Multiplexing, OFDM)采样时钟同步问题, 提出了一种适合于软件无线电(Software-Defined Radio, SDR)接收机的全数字实现方案. 该方案的整体结构基于经典的Gardner环路, 借助联合迭代估计算法来进行误差的动态跟踪, 并通过对接收信号进行异步重采样来实现采样时钟误差的实时校正. 误差检测环节不仅能消除载波频率误差的影响, 还可以在维持环路的响应速度的同时提高误差检测的精度. 误差校正环节利用一种简单的动态延迟技术来对信号重采样进行直接控制, 尽管增加了一些处理延迟, 但能使重采样过程平稳进行. 理论分析和仿真结果表明, 新的采样时钟同步方案在多径信道环境中能有效工作, 算法的性能优于其他同类算法.

关键词: 正交频分复用, 软件无线电接收机, 采样时钟同步, 误差检测, 重采样

Abstract:

The sampling clock error in an OFDM (Orthogonal Frequency Division Multiplexing) receiver will severely degrade the overall system performance. Based on the canonical Gardner loop, a novel sampling clock synchronization scheme suitable for OFDM based software-defined radio (SDR) receivers is proposed, which uses a joint recursive algorithm to track the error and then corrects it by performing asynchronous resampling on the received signal. The proposed error detection method can improve estimation efficiency by eliminating effects of the carrier frequency error while sustaining the loop’s dynamic performance. A dynamic delay technique is devised to control the resampling process, which can smoothly adjust the incoming data stream without sampling disturbance. Theoretical analysis and simulation results indicate that the proposed scheme outperforms other techniques and works well in the multipath channel.

Key words: OFDM, SDR receiver, sampling clock synchronization, error detection, resampling