Residual Carrier and Sampling Frequency Synchronization in Multiuser OFDM Systems

This contribution considers the estimation and compensation of residual multiple carrier frequency offsets (CFOs) and sampling frequency offsets (SFOs) in the uplink of a multiuser OFDM system. Based on the observation of a user-dependent phase rotation, an approximate maximum-likelihood (ML) estimator is proposed in order to estimate the CFOs and SFOs to track the phase in a post-synchronization step. Bit-error-ratio (BER) simulations show that the system performance degradation due to (small) frequency mismatches is negligible if the proposed method is applied

[1]  Yeheskel Bar-Ness,et al.  Multiple phase noise correction for OFDM/SDMA , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[2]  Hugo De Man,et al.  A combined OFDM/SDMA approach , 2000, IEEE Journal on Selected Areas in Communications.

[3]  Michele Morelli,et al.  Timing and frequency synchronization for the uplink of an OFDMA system , 2004, IEEE Transactions on Communications.

[4]  Per Ödling,et al.  A time and frequency synchronization scheme for multiuser OFDM , 1999, IEEE J. Sel. Areas Commun..

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