A low-complexity ICI cancellation scheme in frequency domain for OFDM in time-varying multipath channels

In orthogonal frequency division multiplexing (OFDM) systems, time variation of multipath channels over an OFDM block period leads to a loss of orthogonality among subcarriers, resulting in intercarrier interference (ICI). In this paper, based on the analysis of the symbol energy distribution and the ICI generation mechanism, we propose a low-complexity partial minimum mean-squared error (MMSE) with successive detection (PMMSESD) scheme in frequency domain to mitigate ICI caused by time-varying channels. Each time, the proposed method detects the symbol with the largest received signal-to-interference-plus-noise ratio (SINR) among all the undetected symbols, using an MMSE detector only considering the interference of several neighborhood subcarriers. Analysis and simulation results show that our PMMSESD method can effectively reduce the ICI with low computational complexity, it outperforms the MMSE method at relatively high E_b/N₀ , and its performance is close to the MMSE with successive detection (MMSESD) method in the relatively low Doppler frequency region