A Novel Trellis-Coded Binary Modulation for Extreme Coverage in 6G

In this paper, a novel binary waveform with low peak-to-average power-ratio (PAPR) and low out-of-band (OOB) emissions is presented, targeting at extreme uplink coverage solutions towards the 6G era. It uses the discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) signal model, as the baseline, togetherwith quadrature phase-shift keying (QPSK) modulation symbols, similar to the widely considered $\pi / 2$ binary phase-shift keying ($\pi / 2$-BPSK). The proposed approach further incorporates trellis-coding in a way which avoids sharp phase transitions in the generated signal, resulting in greatly reduced PAPR and OOB emissions. Additionally, while linear filtering based spectrum shaping has been widely considered in recent low-PAPR waveform studies, we propose to use phase interpolation to increase the sampling rate. This is nonlinear operation, but it helps to significantly reduce the PAPR compared to linear spectrum shaping. This can be achieved both with and without bandwidth extension. Further enhancement to the spectrum localization is achieved by improving the phase continuity of the generated signal, avoiding excessive phase transitions between consecutive transform-precoded OFDM symbols and between each main symbol and its cyclic prefix (CP).