Motivated by the convergence of terrestrial cellular networks with satellite networks, we consider an adaptation of offset quadrature phase shift keying (OQPSK), used with single-carrier waveform in traditional satellite systems, to discrete Fourier transform spread (DFT-s-) orthogonal frequency-division multiplexed (OFDM) waveform employed in the uplink of terrestrial systems. We introduce a new order-one constellation modulation, termed repeated-and-offset QPSK (RO-QPSK), derive its basic properties, and compare it with pi/2-BPSK with frequency-domain spectral shaping (FDSS), as supported in 5G. RO-QPSK naturally produces a Hann-window-shaped spectrum, resulting in a very low maximum peak-to-average power ratio (PAPR) on the order of 2 dB. Moreover, with single-tap equalization and symbol combining at the receiver, RO-QSPK can improve the signal-to-interference-plus-noise (SINR) compared to pi/2-BPSK with FDSS, in narrowband and/or moderately frequency-selective channels, as encountered in satellite communications. A moderate FDSS can also be combined with RO-QSPK to further reduce the PAPR while providing similar performance. Of independent interest, general SINR expressions for DFT-s-OFDM are also provided.

翻译：受地面蜂窝网络与卫星网络融合趋势的驱动，本文研究将传统卫星系统中与单载波波形结合使用的偏移正交相移键控（OQPSK）技术，适配应用于地面系统上行链路所采用的离散傅里叶变换扩展正交频分复用（DFT-s-OFDM）波形。我们提出一种新的一阶星座调制方案，称为重复与偏移QPSK（RO-QPSK），推导了其基本特性，并将其与5G标准中支持的、采用频域频谱成形（FDSS）的π/2-BPSK进行了比较。RO-QPSK天然产生汉宁窗形频谱，从而可实现极低的最大峰均功率比（PAPR），其值约为2 dB。此外，在卫星通信中常见的窄带和/或中等频率选择性信道条件下，通过在接收端采用单抽头均衡与符号合并，RO-QPSK相比采用FDSS的π/2-BPSK能够改善信号与干扰加噪声比（SINR）。也可将适度的FDSS与RO-QPSK结合，在提供相近性能的同时进一步降低PAPR。作为独立的研究贡献，本文还给出了DFT-s-OFDM系统通用的SINR表达式。