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

• Original Articles • Previous Articles     Next Articles

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 E-mail:neo.hao@gmail.com

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