AI 中文总结
针对不完善信道与紧功率预算下的多用户下行波束成形，提出结合定点最小功率与保形风险控制的CRCBeam方法，在有限样本下控制服务中断风险并满足功率预算。
AI 中文摘要
我们考虑在信道状态信息不完善且发射功率预算紧张的情况下，具有规定信干噪比（SINR）要求的多用户下行链路波束成形问题。鲁棒最坏情况设计通常需要易处理的信道误差模型，并且可能无法产生满足功率预算的可行波束成形器。为缓解这些问题，我们提出了用于波束成形的保形风险控制（CRCBeam），该方法将经典定点最小功率波束成形与保形风险控制相结合，利用估计信道与真实信道的校准样本对来校准SINR余量。在可交换性条件下，CRCBeam对服务中断风险提供有限样本控制，该风险定义为当至少一个用户未能达到其SINR目标时进行发射的概率。CRCBeam不需要参数化信道误差模型，并且仅在满足功率预算时发射。使用导频污染信道误差模型的数值实验证实，CRCBeam在满足功率预算的同时实现了服务中断风险控制。相比之下，最坏情况鲁棒基线方法，即高斯球和保形球波束成形，要么未达到目标风险，要么超出功率预算。
英文摘要
We consider multiuser downlink beamforming with prescribed signal-to-interference-plus-noise ratio (SINR) requirements under imperfect channel state information and a tight transmit power budget. Robust worst-case designs often require tractable channel-error models and may not yield feasible beamformers that meet the power budget. To alleviate these issues, we propose conformal risk control for beamforming (CRCBeam), which combines the classical fixed-point minimum-power beamforming with conformal risk control to calibrate an SINR margin from calibration sample pairs of estimated and true channels. Under exchangeability, CRCBeam provides finite-sample control over served-outage risk, which is the probability of transmitting when at least one user fails to meet its SINR target. CRCBeam requires no parametric channel-error model and transmits only when the power budget is met. Numerical experiments using a pilot contamination channel error model corroborate that CRCBeam achieves the served-outage risk while meeting the power budget. In contrast, worst-case robust baselines, Gaussian-ball and conformal-ball beamforming, either do not meet the target risk or exceed the power budget.
Comments5 pages with references on the 5th page
