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arXiv 2305.08081cs.ITcs.AImath.IT
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深度学习赋能的Type-II码本:增强CSI反馈的新范式

Deep Learning Empowered Type-II Codebook: New Paradigm for Enhancing CSI Feedback

Beijing National Research Center for Information Science and Technology(北京信息科学与技术国家研究中心);Tsinghua University(清华大学);Shenzhen International Graduate School, Tsinghua University(清华大学深圳国际研究生院);Huawei Technologies Company, Ltd.(华为技术有限公司)

Ke Ma, Yiliang Sang, Yang Ming, Jin Lian, Chang Tian, Zhaocheng Wang

AI总结:

本文提出深度学习赋能R17 Type-II码本的CSI反馈新范式,通过优化角度-时延域端口选择、基于稀疏结构重建下行CSI及二阶段损失函数,实现和速率性能提升超10%。

摘要:

基于深度学习的频分双工系统信道状态信息(CSI)反馈在学术界和工业界引起了广泛关注。本文聚焦于将超五代(B5G)无线系统中的Type-II码本与深度学习相结合,以增强CSI反馈的性能。与Release 16中的对应方案不同,Release 17(R17)中的Type-II码本利用上行链路和下行链路信道之间的角度-时延域部分互易性,选择部分角度-时延域端口用于测量和反馈下行CSI,其中传统深度学习方法的性能因稀疏结构的缺乏而受到限制。为解决这一问题,我们提出了采用深度学习来提升R17 Type-II码本性能的新范式。首先,考虑到上行链路信道相对较低的信噪比,利用深度学习来优化主导角度-时延域端口的选择,其中采用focal loss来解决类别不平衡问题。其次,我们提出在基站基于R17 Type-II码本的反馈,通过深度学习的方式重建下行CSI,其中稀疏结构的信息可以被有效利用。最后,设计了一个加权捷径模块以促进精确重建,并提出了一种结合均方误差和和速率的二阶段损失函数,以适应实际的多用户场景。仿真结果表明,与传统的R17 Type-II码本和深度学习基准相比,我们提出的角度-时延域端口选择和CSI重建范式可以将和速率性能提升超过10%。

英文摘要:

Deep learning based channel state information (CSI) feedback in frequency division duplex systems has drawn much attention in both academia and industry. In this paper, we focus on integrating the Type-II codebook in the beyond fifth-generation (B5G) wireless systems with deep learning to enhance the performance of CSI feedback. In contrast to its counterpart in Release 16, the Type-II codebook in Release 17 (R17) exploits the angular-delay-domain partial reciprocity between uplink and downlink channels and selects part of angular-delay-domain ports for measuring and feeding back the downlink CSI, where the performance of the conventional deep learning methods is limited due to the deficiency of sparse structures. To address this issue, we propose the new paradigm of adopting deep learning to improve the performance of R17 Type-II codebook. Firstly, considering the relatively low signal-to-noise ratio of uplink channels, deep learning is utilized to refine the selection of the dominant angular-delay-domain ports, where the focal loss is harnessed to solve the class imbalance problem. Secondly, we propose to reconstruct the downlink CSI by way of deep learning based on the feedback of R17 Type-II codebook at the base station, where the information of sparse structures can be effectively leveraged. Finally, a weighted shortcut module is designed to facilitate the accurate reconstruction, and a two-stage loss function with the combination of the mean squared error and sum rate is proposed for adapting to actual multi-user scenarios. Simulation results demonstrate that our proposed angular-delay-domain port selection and CSI reconstruction paradigm can improve the sum rate performance by more than 10% compared with the traditional R17 Type-II codebook and deep learning benchmarks.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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