Low peak-to-average-power ratio (PAPR) transmissions significantly improve the cell coverage as they enable high power transmissions without saturating the power amplifier. To support the low PAPR transmissions, π/2-BPSK-based data and DMRS are introduced in the latest version of 5G NR specifications. In addition to that, the spatial multiplexing support is also extended to π/2-BPSK data transmissions. The DMRS sequences corresponding to these spatial streams (users) are frequency division multiplexed (FDM). However, the spectrum shaping process employed in the generation of π/2-BPSK waveforms is frequency selective and hence results in asymmetric spectrum shaping effect on DMRS sequences, when they are frequency multiplexed. This subsequently results in a non-uniform block error (BLER) and PAPR performances across the spatial users, which in turn may result in inter user interference across the spatial users. In this paper, we propose two transmitter architectures, namely method 1 and method 2, to generate low PAPR π/2-BPSK-based DMRS waveforms. The proposed architectures ensure that the spectrum shaping effect is uniform across all the spatial streams. We corroborate through simulations that the proposed architectures will result in identical block error and PAPR performances across all the spatial streams.

低峰均功率比（PAPR）传输可在不使功率放大器饱和的情况下实现高功率传输，从而极大地改善了小区覆盖范围。为了支持低PAPR传输，在最新版本的5G NR规范中引入了基于π / 2-BPSK的数据和DMRS。除此之外，空间复用支持还扩展到π / 2-BPSK数据传输。对应于这些空间流（用户）的DMRS序列被频分复用（FDM）。但是，在生成π时使用的频谱整形过程/ 2-BPSK波形具有频率选择性，因此当对它们进行频率多路复用时，会对DMRS序列产生不对称的频谱整形效果。随后，这将导致整个空间用户的非均匀块错误（BLER）和PAPR性能，进而可能导致空间用户之间的用户间干扰。在本文中，我们提出了两种发射器架构，即方法1和方法2中，以产生低PAPR π / 2基于-BPSK-DMRS波形。所提出的架构确保了频谱整形效果在所有空间流中均一。通过仿真，我们证实了所提出的体系结构将在所有空间流中产生相同的块误差和PAPR性能。