The Effect of Imperfect Carrier Frequency Offset Estimation on OFDMA Uplink Transmission

Since carrier frequency offset destroys user´s signal orthogonality in orthogonal frequency-division multiplexing access (OFDMA) uplink transmission, resulting in an interference-limited system, its estimation/correction is very important. The residual carrier frequency offset of each user contributes inter-carrier-interference (ICI) and multiple-user-interference (MUI) to other users. In this paper, the effect of the carrier frequency offset on OFDMA uplink is analyzed. We first analyze the average uplink capacity losses as well as the signal-to-interference-and-noise ratio (SINR) reduction due to the carrier frequency offsets, and then discuss the capacity increases by using adaptive power allocation. The averaged bit error rate (BER) performance with the carrier frequency offsets on OFDMA uplink is also analyzed.