While cell-free massive MIMO (CF-mMIMO) offers both uniform and high network-wide throughput in static networks, its performance in a mobile network is not yet fully addressed. In this paper, we evaluate the performance of a mobile CF-mMIMO network under a comprehensive throughput model and show that it suffers from large performance degradation due to the combined effect of channel aging and handover delay. To improve the performance of CF-mMIMO under mobility, we propose a fairness-differentiated handover scheme. Our scheme differentiates the handover policy for different users by their channel conditions compared to a threshold based on Jain's fairness index, in order to prioritize handovers for the poorly served users. We present an extensive evaluation of the mobile throughput performance of our handover scheme with realistic urban network distributions and UE mobility patterns. Our results show that our scheme significantly outperforms the existing literature benchmarks when considering both channel aging and handover delay cost. Importantly, the advantage of UE-centric over network-centric CF-mMIMO, of uniformly good performance over the network, is uniquely preserved under mobility by our handover scheme. We thus show that CF-mMIMO can be a feasible architecture for practical mobile networks.

翻译：尽管无蜂窝大规模多输入多输出（CF-mMIMO）技术在静态网络中能提供均匀且高水平的全网吞吐量，但其在移动网络中的性能尚未得到充分研究。本文基于综合吞吐量模型评估移动CF-mIMO网络的性能，结果表明由于信道老化与切换延迟的共同影响，系统性能会出现显著下降。为提升移动环境下CF-mMIMO的性能，我们提出一种差异化公平性切换方案。该方案通过将用户信道条件与基于Jain公平性指数的阈值进行比较，为不同用户制定差异化的切换策略，从而优先保障服务质量较差用户的切换需求。我们采用实际城市网络分布与用户设备移动模式，对所提切换方案的移动吞吐量性能进行了全面评估。结果表明，在同时考虑信道老化与切换延迟代价的情况下，本方案显著优于现有文献基准方案。尤为重要的是，通过本切换方案，以用户为中心相较于以网络为中心的CF-mMIMO架构所具备的全网性能均匀性优势，在移动场景下得以完整保持。由此证明，CF-mMIMO可成为实际移动网络的可行架构方案。