Window function and interpolation algorithm for OFDM frequency-offset correction

In orthogonal frequency-division multiplexing (OFDM) digital communication systems, an uncorrected frequency offset can lead to a severe degradation of the system performance. The paper describes a technique to mitigate the influence of frequency offset on system performance by applying a weighted discrete Fourier transform (DFT) to a novel OFDM frequency-assignment scheme in which null carriers are regularly inserted among modulated data carriers. This frequency-assignment scheme makes possible the application of a window function at the demodulator to broaden the signal spectrum and renders the demodulated signal more immune to the influence of frequency offset. In addition, a variant of this frequency-assignment scheme also leads to a DFT-based measurement technique for easy and accurate determination of the frequency offset. Interpolation algorithms and frequency-assignment schemes suitable for both initial frequency acquisition and subsequent frequency tracking are described in detail. The Rife and Vincent (Class-I) windows (see Rife, D.C. and Vincent, G.A., Bell Syst. Tech. J., vol.49, p.197-228, 1976) are examined and their estimation results are obtained for an additive white Gaussian noise (AWGN) and a multipath fading channel.

[1]  Robert Boorstyn,et al.  Single tone parameter estimation from discrete-time observations , 1974, IEEE Trans. Inf. Theory.

[2]  F. Harris On the use of windows for harmonic analysis with the discrete Fourier transform , 1978, Proceedings of the IEEE.

[3]  R. Chang Synthesis of band-limited orthogonal signals for multichannel data transmission , 1966 .

[4]  Dario Petri,et al.  Weighting effect on the discrete time Fourier transform of noisy signals , 1991 .

[5]  Per Ola Börjesson,et al.  ML estimation of time and frequency offset in OFDM systems , 1997, IEEE Trans. Signal Process..

[6]  H. Nogami,et al.  A frequency and timing period acquisition technique for OFDM systems , 1995, Proceedings of 6th International Symposium on Personal, Indoor and Mobile Radio Communications.

[7]  Sayfe Kiaei,et al.  Class of cyclic-based estimators for frequency-offset estimation of OFDM systems , 2000, IEEE Trans. Commun..

[8]  D. C. Rife,et al.  Use of the discrete fourier transform in the measurement of frequencies and levels of tones , 1970, Bell Syst. Tech. J..

[9]  R. R. Boorstyn,et al.  Multiple tone parameter estimation from discrete-time observations , 1976, The Bell System Technical Journal.

[10]  Paul H. Moose,et al.  A technique for orthogonal frequency division multiplexing frequency offset correction , 1994, IEEE Trans. Commun..

[11]  Tiejun Lv,et al.  ML estimation of timing and frequency offset using multiple OFDM symbols in OFDM systems , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[12]  Che-Ho Wei,et al.  A low-complexity frame synchronization and frequency offset compensation scheme for OFDM systems over fading channels , 1999 .

[13]  Donald C. Cox,et al.  Robust frequency and timing synchronization for OFDM , 1997, IEEE Trans. Commun..

[14]  Michael D. Zoltowski,et al.  OFDM blind carrier offset estimation: ESPRIT , 2000, IEEE Trans. Commun..