Time-Domain vs. Frequency-Domain Equalization for FTN Signaling

Faster-than-Nyquist (FTN) signaling has been recognized as a promising technique for next-generation high data rate communications. By intentionally reducing the symbol interval, FTN signaling is capable of transmitting more symbols than classic Nyquist signaling within the same time period and bandwidth. However, the intentional non-orthogonality of the bandlimited signaling pulses imposes severe inter-symbol interference (ISI), which requires powerful equalization at the receiver. Hence, we embark on the comparison of time- and frequency-domain equalization for FTN signaling both by theoretical analysis and numerical simulations. It is shown that frequency-domain equalization fails to reliably detect the FTN signal with a low FTN packing factor, while the time-domain equalization still performs well.