Multiple CFO compensation for IFDMA in high-speed wireless communications

For the uplink interleaved single carrier frequency division multiple access (SC-FDMA) system, one of the main problems is that the multiple carrier frequency offsets (CFO), caused by Doppler shift in high-speed wireless communications, will cause severe inter-subcarrier interference (ICI), so as to influence the system performance. In this paper, we propose an effective multiple CFO compensation scheme, for reducing the ICI influence in the uplink interleaved SC-FDMA. On the one hand, the optimal CFO compensation value, which maximizes the signal-to-interference ratio (SIR), is achieved to compensate the CFO for each user at the receiver. On the other hand, the residual ICI is analyzed and an improved minimum mean square error (MMSE) frequency domain equalizer (FDE) receiver is developed which suppresses both ICI and noise. Theoretical analysis and simulation results show that the proposed CFO compensation scheme can effectively reduce the influence of ICI and im-prove the system performance.