Joint optimization of precoding and constellation shaping for faster-than-nyquist signaling

Faster-than-Nyquist (FTN) signaling is a potential scheme for the sixth generation (6G) communication system to improve the spectral efficiency (SE). In this paper, we propose a joint optimization algorithm of precoding and constellation shaping for FTN signaling, which is based on simulated optimization via the bare bones particle swarm optimization (BBPSO). The information-theoretical analysis and simulated error performance show that the proposed method is efficient, which can get a significant improvement in terms of average mutual information (AMI) and bit error rate (BER) performance. The simulated BER results verify the theoretical AMI analysis. Compared with the conventional regular 16QAM FTN scheme, when BER is at 10⁻⁵, the joint optimized scheme can obtain 0.50 dB and 0.60 dB performance gain with SE at 3.077 bits/s/Hz and 3.282 bits/s/Hz, respectively. Therefore, the proposed scheme is reliable, and thus suitable for the 6G communication.