Cell-free (CF) massive multiple-input multiple-output (MIMO) systems, which exploit many geographically distributed access points to coherently serve user equipments via spatial multiplexing on the same time-frequency resource, has become a vital component of the next-generation mobile communication networks. Theoretically, CF massive MIMO systems have many advantages, such as large capacity, great coverage, and high reliability, but several obstacles must be overcome. In this article, we study the paradigm of CF massive MIMO-aided mobile communications, including the main application scenarios and associated deployment architectures. Furthermore, we thoroughly investigate the challenges of CF massive MIMO-aided mobile communications. We then exploit a novel predictor antenna, hierarchical cancellation, rate-splitting and dynamic clustering system for CF massive MIMO. Finally, several important research directions regarding CF massive MIMO for mobile communications are presented to facilitate further investigation.

翻译：无小区(CF)大规模多输入多输出(MIMO)系统通过大量地理分布接入点在同一时频资源上利用空间复用技术为用户设备提供相干服务，已成为下一代移动通信网络的关键组成部分。理论上，CF大规模MIMO系统具有大容量、广覆盖、高可靠性等诸多优势，但仍需克服若干障碍。本文研究了CF大规模MIMO辅助移动通信的范式，包括主要应用场景及相关部署架构。此外，我们深入探究了CF大规模MIMO辅助移动通信面临的挑战，进而开发出适用于CF大规模MIMO的新型预测天线、分层干扰消除、速率分割与动态聚类系统。最后，提出了移动通信中CF大规模MIMO的几个重要研究方向，以促进进一步探索。