Functional splitting, referred as X-haul, is introduced in the 5G networks to support flexibility and meet service requirements. Each split option has a different impact on latency and bandwidth characteristics. Depending on the split, a certain amount of redundant resources is required to provide resiliency against outages or failures, as in the case of the uRLLC service. This paper proposes novel reliable function placement algorithms for functional splitting to guarantee service continuity in case of single CU/DU or link failure, namely based on dedicated and shared path protection principles. The proposed techniques not only provide a scalable approach to design full protection against single failure but also exhibit significant savings in terms of network resources, by suitably sharing redundant backup resources. The obtained results show significant improvement in terms of bandwidth saving and multiplexing gain with respect to conventional C-RAN fronthaul, depending on the distance constraints, thus suggesting design criteria for 5G aggregation networks.

在5G网络中引入了称为X-haul的功能拆分，以支持灵活性并满足服务要求。每个拆分选项对延迟和带宽特性都有不同的影响。根据拆分情况，与uRLLC服务一样，需要一定数量的冗余资源来提供针对中断或故障的弹性。本文提出了一种新的可靠的功能分配算法，用于功能划分，以确保在单个CU / DU或链路故障的情况下的服务连续性，即基于专用和共享路径保护原理。所提出的技术不仅提供了可扩展的方法来设计针对单一故障的全面保护，而且还通过适当地共享冗余备份资源而在网络资源方面显示出显着的节省。