Faster-Than-Nyquist Signaling With Index Modulation

In this letter, we propose a novel faster-than-Nyquist (FTN) transmission scheme relying on the time-domain single-carrier index-modulation (IM) concept. In the proposed FTN with IM (FTN-IM) transmitter, a subset of time-domain FTN symbols are activated, where the combination of the activated symbols conveys additional information further to the classic amplitude phase shift keying. Owing to the explicit benefit of sparse FTN-IM signaling, the FTN-specific inter-symbol interference is mitigated in an effective manner, hence attaining a higher spectral efficiency than the conventional FTN counterpart. Furthermore, a low-complexity noise-whitening frequency-domain equalization is developed for our FTN-IM receiver. In order to demonstrate the performance advantage of the proposed FTN-IM scheme over the conventional FTN counterpart, we show that a minimum Euclidean distance of proposed FTN-IM signaling is higher than that of the conventional FTN signaling, while providing their numerical performance comparisons in terms of error rates.