Probabilistic Shaping Combined With Spatially-Coupled LDPC Code in FTN System

In this paper, we propose a combination of probabilistic shaping and spatially-coupled low-density parity-check code in Faster-Than-Nyquist system. At the transmitter, a constellation signal conforming to a certain probability distribution is generated. After passing through the additive white Gaussian noise channel, the receiver uses the iterative equalization method of stream decoding to decode due to the before-and-after correlation characteristics of the spatially-coupled low-density parity-check codeword. The system proposed in this paper is simulated based on the probabilistic shaping 16QAM format. With the spectral efficiency of 2.67 bit/s/Hz, the frame error performance under the Faster-Than-Nyquist system and the Nyquist system is compared. It shows that in the Faster-Than-Nyquist system, the probabilistic shaping and spatial-coupling low-density parity-check code combination have 0.83 dB system gain and 0.53 dB shaping gain when compared to Nyquist system.