We study Flexible Functional Split functionality of 5G vRAN controllers in 5G networks. We propose an innovative model, based on a Markov Chain, which can be used to characterize their performance. We consider both infinite and finite-buffer controllers. In the former, frames would not be lost (provided the system works in a stable regime), and we thus focus on the time frames stay at the controller. For the finite-buffer controller, there might be losses, and we analyze the trade-off between time at the controller (which might hinder the stringent delay requirements of 5G services), and loss probability. Matrix-geometric techniques are used to resolve the corresponding Quasi-Birth-Death process. The validity of the proposed model is assessed by means of an extensive experiment campaign carried out over an ad-hoc event-driven simulator, which is also used to broaden the analysis, considering different service rate distributions, as well as the variability of the studied performance indicators. The results show that the proposed model can be effectively exploited to tackle the dimensioning of these systems, as it sheds light on how their configuration impacts the expected delay and loss rate.

中文翻译：

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了解基于5G vRAN控制器的灵活功能拆分的性能：基于马尔可夫链的模型

我们研究5G网络中5G vRAN控制器的Flexible Functional Split功能。我们提出了一个基于马尔可夫链的创新模型，该模型可用于表征其性能。我们同时考虑了无限控制器和有限缓冲区控制器。在前者中，帧不会丢失（只要系统在稳定的状态下工作），因此我们将重点放在控制器的停留时间上。对于有限缓冲控制器，可能会有损失，并且我们分析了控制器时间（这可能会阻碍5G服务的严格延迟要求）与损失概率之间的折衷。矩阵几何技术用于解决相应的准出生死亡过程。拟议模型的有效性是通过在特定事件驱动的模拟器上进行的广泛实验活动进行评估的，考虑到不同的服务费率分布以及所研究的绩效指标的可变性，它也可用于扩大分析范围。结果表明，提出的模型可以有效地利用这些系统的尺寸，因为它揭示了它们的配置如何影响预期的延迟和丢失率。