Massive multiple-input multiple-output (MIMO) is believed to deliver unrepresented spectral efficiency gains for 5G and beyond. However, a practical challenge arises during its commercial deployment, which is known as the ``curse of mobility''. The performance of massive MIMO drops alarmingly when the velocity level of user increases. In this paper, we tackle the problem in frequency division duplex (FDD) massive MIMO with a novel Channel State Information (CSI) acquisition framework. A joint angle-delay-Doppler (JADD) wideband precoder is proposed for channel training. Our idea consists in the exploitation of the partial channel reciprocity of FDD and the angle-delay-Doppler channel structure. More precisely, the base station (BS) estimates the angle-delay-Doppler information of the UL channel based on UL pilots using Matrix Pencil (MP) method. It then computes the wideband JADD precoders according to the extracted parameters. Afterwards, the user estimates and feeds back some scalar coefficients for the BS to reconstruct the predicted DL channel. Asymptotic analysis shows that the CSI prediction error converges to zero when the number of BS antennas and the bandwidth increases. Numerical results with industrial channel model demonstrate that our framework can well adapt to high speed (350 km/h), large CSI delay (10 ms) and channel sample noise.
翻译:大型多投入多重产出(MIMO)被认为为5G及以后的5G(MIMO)提供了无人代表的光谱效率增益。然而,在商业部署期间,即所谓的“流动性诅咒”期间,出现了一个实际的挑战。当用户速度提高时,大规模MIMO的表现令人震惊地下降。在本文中,我们用一个新的频道国家信息(CSI)获取框架来解决频率分解(DFD)大规模MIMIM(CIS)的问题。为频道培训建议了一个联合角度-调频-多普勒(JADDD)宽频谱预译器。我们的想法是利用DDDDDFDAD和角-脱光-多普勒频道结构的部分对等频道。更准确地说,基地台(BS)利用UL模型的角-德莱-多普勒信息水平提高用户速度。然后根据提取的参数对宽频带 JADDDPread-Doppler (JADDD) 宽谱预译器(JADDDD) 宽段(JADDD) 预译器(JADDDDDD) 宽带前导器(JADD) 用于频道培训。之后,用户估计和反馈一些卡数系数系数系数是BSAS 部分的利用部分频道部分频道部分频道的对等的对等的对等,我们BS 和角-DDDFDFDDFDFDFD) 的对等部分部分部分的对等部分的对等部分的对等的对等的利用部分频道的对等的对调, 和角-DFDFDFDFDFDFDRDFDFDR 和角-DFDFDR 和角-DRML-D的对调频带结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构结构的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等的对等。