J4 ›› 2010, Vol. 37 ›› Issue (4): 758-763.doi: 10.3969/j.issn.1001-2400.2010.04.031

• 研究论文 • 上一篇    下一篇

快变信道环境下OFDMA系统的信道估计算法

李丹1,2;冯穗力1;叶梧1;庄宏成3   

  1. (1. 华南理工大学 电子与信息学院,广东 广州  510640;
    2. 韶关学院 计算机科学学院,广东 韶关  512005;
    3. 华为技术有限公司 预研部,广东 深圳  518100)
  • 收稿日期:2009-04-15 出版日期:2010-08-20 发布日期:2010-10-11
  • 通讯作者: 李丹
  • 作者简介:李丹(1980-),女,华南理工大学博士研究生,E-mail: d.li@mail.scut.edu.cn.
  • 基金资助:

    粤港关键领域重点突破项目(20060104-2)

Channel estimation method for OFDMA systems over fast time-varying channels

LI Dan1,2;FENG Sui-li1;YE Wu1;ZHUANG Hong-cheng3   

  1. (1. School of Electronic and Info. Eng., South China Univ. of Tech., Guangzhou  510640, China;
    2. School of Computer Sci., Shaoguan Univ., Shaoguan  512005, China;
    3. Pre-research Dept., Huawei Tech. CO. Ltd, Shenzhen  518100, China)
  • Received:2009-04-15 Online:2010-08-20 Published:2010-10-11
  • Contact: LI Dan

摘要:

现有OFDMA系统时变信道估计方法仍需假设信道在一个符号内平稳,而在高速移动环境下,信道在符号内的时变将造成OFDMA系统子载波间干扰 (ICI).经典的OFDM系统中的时域快时变信道估计方法可以较好地估计出信道在一个符号内的时变,但需要理想等间隔均匀分布于整个频域的导频.针对OFDMA频分多址系统中某一用户占用的频域非均匀导频样式,提出一种适用于OFDMA系统的频域快时变信道估计方法.该方法在频域进行,避开时域处理对等间隔导频的要求,利用频域时变传输函数辅助跟踪估计信道在一个符号内的时变,最终得到信道频域传输矩阵,估计出快变信道符号内时变对系统造成的ICI影响系数.仿真实验从误码率、均方误差两方面验证了该方法的有效性.

关键词: OFDM, OFDMA, 快时变信道, 信道估计, 非均匀导频, 线性模型

Abstract:

Current channel estimation (CE) schemes for OFDMA systems track channel variations symbol by symbol result in ICI when the channel is Time-varying (TV) in one symbol period. However, conventional TV CE methods for OFDM systems need optimal even-pilots to track channel time variations in one symbol period. For practical OFDMA systems, the required even pilot tone is not satisfied. In this paper, we present a pilot-assisted CE method for practical OFDMA systems in TV channels, which is performed in the frequency-domain, avoiding time-domain transformations and does not need even-spaced pilots. The frequency-domain transmission function is employed to estimate channel variations over one OFDMA symbol period. Simulation results show that the proposed method outperforms current OFDMA CE schemes in terms of the symbol-error-rate (SER) and Mean Square Error (MSE).

Key words: OPDM, OFDMA, TV channels, channel estimation, uneven pilot, linear model