This paper elaborates on Conditional Handover (CHO) modelling, aimed at maximizing the use of contention free random access (CFRA) during mobility. This is a desirable behavior as CFRA increases the chance of fast and successful handover. In CHO this may be especially challenging as the time between the preparation and the actual cell change can be significantly longer in comparison to non-conditional handover. Thus, new means to mitigate this issue need to be defined. We present the scheme where beam-specific measurement reporting can lead to CFRA resource updating prior to CHO execution. We have run system level simulations to confirm that the proposed solution increases the ratio of CFRA attempts during CHO. In the best-case scenario, we observe a gain exceeding 13%. We also show how the average delay of completing the handover is reduced. To provide the entire perspective, we present at what expense these gains can be achieved by analyzing the increased signaling overhead for updating the random access resources. The study has been conducted for various network settings and considering higher frequency ranges at which the user communicates with the network. Finally, we provide an outlook on future extensions of the investigated solution.

翻译：本文详细阐述了条件切换（CHO）建模，旨在最大化移动性期间无竞争随机接入（CFRA）的使用。这是一种理想行为，因为CFRA能提升快速且成功切换的概率。在条件切换中，由于准备与实际小区变更之间的时间可能明显长于非条件切换，因此实现这一目标尤为具有挑战性。为此，需要定义新的手段来缓解该问题。我们提出了一种方案，其中基于波束的测量报告可在CHO执行前触发CFRA资源更新。通过系统级仿真，我们验证了所提方案能够提升CHO期间CFRA尝试的比例。在最优场景下，观察到增益超过13%。同时，我们展示了切换完成平均时延的降低情况。为提供全面视角，我们通过分析更新随机接入资源所增加的信号开销，说明了实现这些增益所需付出的代价。本研究针对多种网络配置进行，并考虑了用户与网络通信的较高频段范围。最后，我们展望了所研究方案的未来扩展方向。