Ultra-low end-to-end latency is one of the most important requirements in 5G networks and beyond to support latency-critical applications. Cloud-RAN and MEC are considered as the key driving technology that can help reduce end-to-end latency. However, the use of MEC nodes poses radical changes to the access network architecture. As it brings the processing and the networking services closer to the edge, it often requires network functions (for example, the CU/DU stack and the application processing) to be distributed across different MEC sites. Therefore, a novel transport mechanism is needed to efficiently coordinate and connect network functions across MEC nodes. In order to address this challenge, we propose a novel two-tier virtualized PON transport method with schedulers coordination over a virtualised and sliced MESH-PON architecture. While a MESH-PON architecture enables direct communication between MEC nodes that are hosting CU/DU and/or the application processing, our method provides a two tier virtualised PON transport scheme with coordinated schedulers. This approach greatly reduces latency incurred in transporting signals across the different PON tiers, while maintaining the flexibility of the multi-tier methods. We show that our proposed scheme can achieve end-to-end application-level latency below 1ms or 2ms, depending on the network configurations.

翻译：超低端到端延迟是5G及未来网络中支持延迟关键型应用的最重要需求之一。云无线接入网和移动边缘计算被认为是能够帮助降低端到端延迟的关键驱动技术。然而，使用MEC节点对接入网架构带来了根本性改变。由于它将处理与网络服务推向边缘，往往需要网络功能（例如CU/DU协议栈和应用处理）分布在不同的MEC站点上。因此，需要一种新型传输机制来高效协调和连接MEC节点间的网络功能。针对这一挑战，我们提出了一种新颖的两级虚拟化PON传输方法，该方法在虚拟化且切片的MESH-PON架构上实现调度器协调。MESH-PON架构可支持承载CU/DU和/或应用处理的MEC节点之间的直接通信，而我们的方法则提供了一种具有协调调度器的两级虚拟化PON传输方案。这种方法在保持多级方法灵活性的同时，显著降低了跨不同PON层级传输信号时产生的延迟。我们证明，根据网络配置的不同，所提出的方案可实现低于1毫秒或2毫秒的端到端应用级延迟。