数字孪生辅助的MU-MIMO下行链路系统用户预筛选
Digital Twin-Aided Prescreening for User Scheduling in MU-MIMO Downlink Systems
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中文总结 AI 辅助
该研究针对MU-MIMO下行链路用户调度中瞬时CSI获取受限的问题，提出DiTUS框架，通过DT辅助预筛选用户，仿真显示其性能优于SUS方案，保留了多用户分集增益。
中文摘要 AI 辅助
在密集部署场景中，大规模多用户多输入多输出（MU-MIMO）基站在每个调度间隔内仅能为有限数量的用户子集获取瞬时信道状态信息（CSI），这限制了多用户分集。为此，我们提出了数字孪生用户预筛选（DiTUS）框架，该框架基于数字孪生（DT）技术，在获取瞬时CSI前识别出有潜力的用户。DiTUS利用DT推断的到达角和路径功率形成空间协方差；可选的高斯过程（GP）校准可缓解路径功率偏差，而聚合协方差的主导秩-r特征空间则生成公共参考波束。DiTUS通过两种规则对用户池进行预筛选：低复杂度的投影能量规则DiTUS-P，或促进空间兼容性的贪心对数行列式规则DiTUS-L。采用两级协议：从入围用户收集标量波束报告，仅向调度用户请求r维有效信道向量；该框架还支持比例公平调度。在DT缺陷下15dB条件下，针对128个候选用户、64用户有效CSI获取预算、64用户入围用户的仿真显示，DiTUS-L的性能为35.06±0.49 bps/Hz，而采用64用户全维CSI的半正交用户选择（SUS）性能为30.28±0.60 bps/Hz，表明基于DT的预筛选在获取有效信道向量前识别出强且空间兼容的用户，保留了显著的多用户分集增益。
英文摘要
In dense deployments, massive multi-user multiple-input multiple-output (MU-MIMO) base stations can acquire instantaneous channel state information (CSI) for only a limited subset of users per scheduling interval, restricting multiuser diversity. We therefore propose Digital Twin User pre-Screening (DiTUS), a digital-twin (DT)-aided framework that identifies promising users before instantaneous CSI acquisition. DiTUS forms spatial covariances from DT-inferred departure angles and path powers. Optional Gaussian-process (GP) calibration mitigates path-power bias, while the dominant rank-r eigenspace of the aggregate covariance yields common reference beams. It prescreens the pool using DiTUS-P, a low-complexity projection-energy rule, or DiTUS-L, a greedy log-determinant rule that promotes spatial compatibility. A two-level protocol collects scalar beam reports from shortlisted users and requests r-dimensional effective-channel vectors only from the scheduled set. The framework also supports proportional-fair scheduling. At 15 dB under DT imperfections, simulations with 128 candidates, a 64-user effective-CSI acquisition budget, and a 64-user shortlist show that DiTUS-L achieves 35.06 +/- 0.49 bps/Hz versus 30.28 +/- 0.60 bps/Hz for semi-orthogonal user selection (SUS) with full-dimensional CSI from 64 users, demonstrating that DT-based prescreening preserves substantial multiuser-diversity gains by identifying strong, spatially compatible users before acquiring effective-channel vectors.
