The effect of a common carrier frequency offset (CFO) at the OFDMA receiver is explored in this paper. In conventional CFO compensation methods for OFDMA systems, the CFOs are usually compensated for by directly eliminating the intercarrier interference (ICI) caused by the residual CFOs for individual users. Besides the ICI, the multiuser interference can be also introduced at the OFDMA receiver due to different CFO values for the users. From the theoretical and simulated analysis, we find that the mean square error performance of the demodulated output signal is related to a common CFO value which can be adjusted before the DFT. A new common CFO estimation method is then verified by numerical results to demonstrate that a better bit error rate performance can be obtained by using the proposed common CFO correction algorithm compared to conventional CFO compensation methods in OFDMA systems.
['Dah-Chung Chang', 'Yen-Heng Lai', 'Yi-Chia Hsu']
Effect of common carrier frequency offset at the OFDMA receiver