We consider a robust beamforming problem where large amount of downlink (DL) channel state information (CSI) data available at a multiple antenna access point (AP) is used to improve the link quality to a user equipment (UE) for beyond-5G and 6G applications such as environment-specific initial access (IA) or wireless power transfer (WPT). As the DL CSI available at the current instant may be imperfect or outdated, we propose a novel scheme which utilizes the (unknown) correlation between the antenna domain and physical domain to localize the possible future UE positions from the historical CSI database. Then, we develop a codebook design procedure to maximize the minimum sum beamforming gain to that localized CSI neighborhood. We also incorporate a UE specific parameter to enlarge the neighborhood to robustify the link further. We adopt an indoor channel model to demonstrate the performance of our solution, and benchmark against a usually optimal (but now sub-optimal due to outdated CSI) maximum ratio transmission (MRT) and a subspace based method.We numerically show that our algorithm outperforms the other methods by a large margin. This shows that customized environment-specific solutions are important to solve many future wireless applications, and we have paved the way to develop further data-driven approaches.

翻译：我们考虑一个鲁棒波束赋形问题，其中多天线接入点（AP）拥有大量下行（DL）信道状态信息（CSI）数据，这些数据用于提升用户设备（UE）的链路质量，以支持面向6G及超5G的特定环境初始接入（IA）或无线能量传输（WPT）等应用。由于当前时刻可用的下行CSI可能不完善或过时，我们提出一种新颖方案：利用天线域与物理域之间（未知的）相关性，从历史CSI数据库中定位未来可能出现的UE位置。随后，我们开发了一种码本设计流程，以最大化该局部CSI邻域的最小和波束赋形增益。同时，我们引入了一个UE特定参数来扩大邻域范围，从而进一步增强链路的鲁棒性。我们采用室内信道模型来演示所提方案的性能，并将其与通常最优（但因CSI过时而变为次优）的最大比传输（MRT）及基于子空间的方法进行基准对比。数值结果表明，我们的算法显著优于其他方法。这证明了定制化环境特定解决方案对于解决众多未来无线应用的重要性，同时也为开发更多数据驱动方法奠定了基础。