ICI Mitigation Based on CIR Interpolation for Wideband SC-FDE System with High-order Modulation in Dynamic Scenario

Single-carrier frequency domain equalization (SC-FDE) technology is widely used in millimeter wave frequency, and the application of large bandwidth with high spectral efficiency is also being developing rapidly. However, the high rate means more sensitivity to multipath, so we need to increase the guard interval and data block length which introduces large inter-carrier interference (ICI) in high-speed dynamic scenario. The ICI will degrade the performance of higher-order modulation. In this paper, an improved ICI mitigation method is proposed. Under the condition of large normalized carrier frequency offset (NCFO), the channel estimation results are interpolated to reconstruct the time-varying channel impulse response (CIR) matrix, and the frequency domain equalization is performed afterwards. In addition, the SIR analysis and performance simulation are carried out when the normalized carrier frequency offset is up to 20% with 64QAM modulation. The simulation results show that compared with the original linear interpolation approximation, the 2nd and the 3rdorder interpolation approximations have signal-to-interference ratio (SIR) gains of 4dB and 6.5dB respectively. The simulation results illustrate that the bit error rate (BER) is consistent with the SIR. This method is suitable for high-order modulation communication systems with high dynamic and high bandwidth.