SliAvailRAN: Availability-Aware Slicing and Adaptive Function Placement in Virtualized RANs

The rise of 5G mobile networks necessitated virtualized Radio Access Network (vRAN) deployment, whereby radio functions are softwarized. This involves disaggregating traditional Baseband Units (BBUs) into Radio units (RU), Distributed Units (DUs), and Centralized Units (CUs) and dynamically instantiating radio network functions onto these for efficient resource optimization. However, establishing a robust vRAN for 5 G encounters challenges due to diverse application scenarios like Ultra-Reliable Low-Latency Communication (URLLC), Enhanced Mobile Broadband (eMBB), and Massive Machine Type Communication (mMTC), each with a specific service requirement. This paper studies the challenges involved in the optimal placement of radio network functions onto the disaggregated vRAN components while slicing the network to support diverse 5 G application scenarios. The paper models a 5 G vRAN and proposes an Integer Linear Programming (ILP) framework - SliAvailRAN, which maximizes the service provider’s profit by optimally allocating virtualized network functions for 5G application scenarios. We evaluate SliAvailRAN on two realistic topologies (with multiple variants) and show results for request acceptance and achieved centralization levels.