Title :
Pilot-based frequency offset estimation in the presence of time-varying DC offset
Author :
Yunus, Umut ; Lin, Hai ; Yamashita, Katsumi
Author_Institution :
Grad. Sch. of Eng., Osaka Prefecture Univ., Osaka, Japan
Abstract :
In OFDM systems, since carrier frequency offset (CFO) destroys the orthogonality among subcarriers, whose estimation/compensation is a critical problem. However, the CFO estimation suffers from DC offset (DCO) generated in low-cost direct-conversion receivers (DCRs). More seriously, in general, DCO is time-varying due to the automatic gain control. In this paper, we propose a novel CFO estimator in the presence of time-varying DCO. It is shown the residual DCO after high-pass filtering varies in a linear fashion. Based on this observation and the periodicity of the training sequence, we derive a CFO estimator independent of DCO. Simulation results show the validity of the proposed estimation method.
Keywords :
OFDM modulation; automatic gain control; frequency estimation; high-pass filters; radio receivers; time-varying filters; wireless LAN; CFO estimation; OFDM systems; automatic gain control; carrier frequency offset; high-pass filtering; low-cost direct-conversion receivers; pilot-based frequency offset estimation; time-varying DC offset; time-varying DCO; DC generators; Digital video broadcasting; Filtering; Frequency estimation; Gain control; Nonlinear filters; OFDM; Sociotechnical systems; Time varying systems; Wireless communication;
Conference_Titel :
Personal, Indoor and Mobile Radio Communications, 2009 IEEE 20th International Symposium on
Conference_Location :
Tokyo
Print_ISBN :
978-1-4244-5122-7
Electronic_ISBN :
978-1-4244-5123-4
DOI :
10.1109/PIMRC.2009.5450362
