Asymptotically optimal low-complexity single-carrier frequency-domain equalizer with time-domain noise prediction in data-like co-channel interference

In this paper, the design of a low-complexity frequency-domain equalizer with time-domain noise prediction (FDE-NP) is considered for single-carrier block transmission in the presence of inter-symbol interference (ISI) and data-like co-channel interference (CCI). Unlike the minimum mean-squared error (MMSE) FDE-NP designed only to suppress the ISI, the equalizer suffers from drastically increased computational complexity especially in feedforward filtering due to the cyclostationary CCI. By exploiting the asymptotic property of the CCI, we derive a low-complexity FDE-NP that jointly suppresses the ISI and the CCI. We also show that the proposed FDE-NP is asymptotically optimal in the sense that the average mean-squared error converges to that of the MMSE FDE-NP as the block length tends to infinity. Numerical results show that the proposed FDE-NP well approximates the MMSE FDE-NP even with moderate block lengths.