Although frequency range 2 (FR2) systems are an essential part of 5G-Advanced and future 3GPP releases, the mobility performance of multi-panel user equipment (MPUE) with hand blockage is still an area open for research and standardization. In this article, a comprehensive study on the mobility performance of MPUE with hand blockage is performed for conditional handover (CHO) and its potential enhancement denoted by fast conditional handover (FCHO). In contrast to CHO, in FCHO the MPUE can reuse earlier target cell preparations after each handover to autonomously execute subsequent handovers. This saves both the signaling overhead associated with the reconfiguration and re-preparation of target cells after each handover and reduces mobility failures. Results have shown that FCHO offers considerable mobility performance gains as compared to CHO for different hand blockage cases that are dependent on the hand position around the MPUE. For the worst-case hand blockage scenario, it is seen that mobility failures reduce by 10.5% and 19.3% for the 60 km/h and 120 km/h mobility scenarios, respectively. This gain comes at the expense of reserving the handover resources of an MPUE for a longer time given that the target cell configurations are not necessarily released after each handover. In this article, the longer resource reservation problem in FCHO is analysed and three different resource reservation optimization techniques are introduced. Results have shown that these optimization techniques not only reduce the resource reservation time but also significantly reduce the signaling overhead at the possible expense of a tolerable degradation in mobility performance.

翻译：尽管频率范围2（FR2）系统是5G-Advanced及未来3GPP版本的关键组成部分，但多面板用户设备（MPUE）在存在手部遮挡情况下的移动性性能仍是待研究与标准化的领域。本文针对条件切换（CHO）及其增强方案——快速条件切换（FCHO），系统研究了MPUE在手部遮挡条件下的移动性性能。与CHO不同，FCHO允许MPUE在每次切换后复用先前已准备的目标小区配置，自主执行后续切换。这一机制既节省了每次切换后重新配置和准备目标小区相关的信令开销，又降低了移动性失败的概率。结果表明，对于取决于MPUE周围手部位置的不同手部遮挡场景，FCHO相比CHO展现出显著的移动性性能增益。在最恶劣的手部遮挡场景下，60 km/h和120 km/h移动场景的移动性失败率分别降低10.5%和19.3%。该增益的代价是，由于目标小区配置未必在每次切换后释放，MPUE的切换资源需被预留更长时间。本文分析了FCHO中的资源预留时间延长问题，并提出了三种不同的资源预留优化技术。结果表明，这些优化技术不仅缩短了资源预留时间，还能在可容忍的移动性性能退化代价下，显著降低信令开销。