Reduced-complexity IBDFE for faster-than-Nyquist communication systems

Faster-than-Nyquist (FTN) signaling is a potential technique to improve spectral efficiency without reducing the bit error rate (BER) performance, but the severe inter-symbol interference (ISI) induced by it may lead to intolerable complexity of maximum likelihood sequence detection (MLSD). An effective method of FTN detection is frequency domain iterative block decision feedback equalizer (IBDFE), as it can achieve performance close to MLSD with much lower complexity. Based on the structure of IBDFE, this paper proposes a reduced-complexity IBDFE (RC-IBDFE) for FTN communication systems. Since a simplified method is employed to design the feedforward and feedback filters, RC-IBDFE further reduces the complexity of FTN detection. Numerical results and analysis demonstrate that the proposed RC-IBDFE has similar BER performance to IBDFE with much stronger robustness and lower complexity.