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OFDM系统中整数倍频偏的最大似然估计

陈晨;李建东;韩钢;赵林靖   

  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:1900-01-01 修回日期:1900-01-01 出版日期:2004-12-20 发布日期:2004-12-20

ML estimation of integer frequency offset in OFDM systems

CHEN Chen;LI Jian-dong;HAN Gang;ZHAO Lin-jing

  

  1. (State Key Lab. of Integrated Service Networks, Xidian Univ., Xi'an 710071, China)
  • Received:1900-01-01 Revised:1900-01-01 Online:2004-12-20 Published:2004-12-20

摘要: 正交频分复用(OFDM)系统的主要缺点之一是其对频率偏移非常敏感.整数倍频偏虽然不会破坏子载波之间的正交性,但会引起接收机数据码元序列的循环移位,从统计的角度看,这时系统误比特率为0.5.该文推导出整数倍频偏的最大似然估计算法,其利用了OFDM两个连续码元的差分关系.通过计算机仿真评估了该算法的性能,并与传统的方法进行了比较.

关键词: 正交频分复用, 整数倍频偏估计, 最大似然算法

Abstract: One of the principal disadvantages of OFDM is very sensitive to frequency offset. Carrier frequency offset can be divided into two parts: an integer one and a fractional one. The integer frequency offset has no effect on the orthogonality among the subcarriers; however it cause a circular shift of data symbols in the receiver, resulting in a BER of 0.5. The maximum likelihood(ML) estimation algorithm for integer frequency offset is derived and it employs the difference relation between two consecutive OFDM symbols. The performance of the ML algorithm is evaluated and compared with the conventional method by computer simulations.

Key words: OFDM, integer frequency offset estimation, maximum likelihood algorithm

中图分类号: 

  • TN919.3