J4 ›› 2010, Vol. 37 ›› Issue (5): 783-788.doi: 10.3969/j.issn.1001-2400.2010.05.002

• 研究论文 • 上一篇    下一篇

OFDMA测距中一种新的定时偏移估计算法

倪浩;任光亮;常义林   

  1. (西安电子科技大学 综合业务网理论及关键技术国家重点实验室,陕西 西安  710071)
  • 收稿日期:2009-03-09 出版日期:2010-10-20 发布日期:2010-10-11
  • 通讯作者: 倪浩
  • 作者简介:倪浩(1978-),男,西安电子科技大学博士研究生,E-mail: neo.hao@gmail.com.
  • 基金资助:

    国家自然科学基金资助(60602063)

Novel timing offset estimation algorithm in OFDMA ranging

NI Hao;REN Guang-liang;CHANG Yi-lin   

  1. (State Key Lab. of Integrated Service Networks, Xidian Univ., Xi'an  710071, China)
  • Received:2009-03-09 Online:2010-10-20 Published:2010-10-11
  • Contact: NI Hao

摘要:

为了在正交频分多址(OFDMA)测距中实现精确的定时偏移估计,提出了一种定时偏移估计新算法.该算法首先利用接收到的OFDMA测距信号估计受定时偏移影响的信道系数.基站分别利用各定时偏移预计值补偿该信道系数,并搜索补偿后信道系数自相关函数的最大峰值,确定定时偏移真实值.由于没有利用接收测距信号的时域相关,所提算法避免了现有的时域相关算法在多径信道中相关峰互相叠加影响估计精度的问题,在多径信道中受到影响较小.还推导了所提算法的理论精度限和复杂度.仿真结果表明,在无线多径信道下,所提算法搜索步长采用一个采样周期时,其10dB信噪比下的定时偏移估计精度比参考算法的精度提高近1倍.

关键词: 正交频分多址(OFDMA), 测距, 定时偏移

Abstract:

In the interest of accurate timing offset estimation in OFDMA ranging, a novel timing offset estimation algorithm is proposed for the process. From the received ranging signal, the channel factors which are affected by the timing offsets are estimated first. Then by compensating the timing offsets with predicted values and searching for the maximum auto-correlation value of the channel factors, the base station can detect the timing offset. Because no correlation of the received ranging signal is included, the adverse effect of several superposed correlation peaks on the estimation accuracy of the available time correlation based algorithms is mitigated, and the proposed algorithm is less affected in the multi-path channels. Furthermore, the theoretical limit of the accuracy is derived for the algorithm, with the complexity given. Simulation results show that when the search step equals one sampling interval, the accuracy of the proposed algorithm is almost two times as high as those of the reference algorithms, at 10dB signal-to-noise-ratio (SNR), in wireless multi-path environments.

Key words: orthogonal frequency division multiple access (OFDMA), ranging, timing offset