低空信道下大规模MIMO信道模型与通信性能分析

Channel Model and Performance Analysis of Massive MIMO in Low-Altitude Channels

摘要:

面向低空宽带上行业务场景，研究低空信道条件下Massive MIMO技术的适用性。针对低空用户视距传播概率高、空间分布具有三维特性且信道时变性较强的特点，建立了考虑Rician衰落、空间相关性和CSI老化效应的上行信道模型，分析了LoS强度、用户角度分布和信道时变性对阵列接收增益、多用户可分性及系统总频谱效率的影响，并对MRC与ZF两种线性接收方式进行了比较分析。结果显示LoS增强有利于提升阵列接收增益，但当用户方向集中时，会因信道相关性升高而削弱空间复用收益；较大的角度分散有助于提高系统频谱效率；同时CSI老化会显著降低接收性能，且在大规模阵列条件下性能损失更为突出；此外低空强LoS环境中Massive MIMO的有利传播特性弱化，MRC接收性能明显弱于ZF接收。

Abstract:

The applicability of Massive MIMO in low-altitude broadband uplink scenarios is investigated under realistic channel conditions. The low-altitude environment, characterized by a high LoS probability, three-dimensional spatial distribution, and significant temporal channel variation, poses unique challenges for multi-antenna systems. An uplink channel model incorporating Rician fading, spatial correlation, and CSI aging effects is established. The impact of LoS strength, user angular distribution, and channel temporal variation on array gain, multi-user separability, and system sum spectral efficiency is analyzed, with a comparative evaluation of MRC and ZF receivers. Results show that while a stronger LoS component improves array gain, it also increases channel correlation when users are angularly concentrated, thereby degrading spatial multiplexing gains. A larger angular spread is found to be beneficial for spectral efficiency. CSI aging significantly degrades reception performance, and this degradation becomes more pronounced as the array size increases. Furthermore, in LoS-dominated low-altitude environments, the favorable propagation property of Massive MIMO is weakened, and MRC reception performs substantially worse than ZF reception.