A Column Generation Algorithm for Dedicated-Protection O-RAN VNF Deployment
Quang Huy Duong, Ibrahim Tamim, Brigitte Jaumard, Abdallah A. Shami · 2022 International Wireless Communications and Mobile Computing (IWCMC) · 2022
The Open Radio Access Network (O-RAN) architecture brings openness, intelligence, and virtualization to RANs, allowing multi-vendor existence, achieving economics of scale, and enabling intelligent management and orchestration. O-RAN components such as near real-time RAN Intelligent Controllers (RICs), O-RAN Central Units (O-CUs), and O-RAN Distributed Unit (O-DUs) can be considered as virtual network functions hosted on the O-Cloud. This virtualization allows network service providers to disaggregate O-RAN functions from their hard-ware, enabling dynamic instantiation of services and reducing their capital and operating costs. However, with openness and virtualization, availability guarantees become more difficult to maintain as the network is now prone to both software and hardware failures. In this paper, we investigate a decomposition model for the design of reliable 0-RAN deployment under a dedicated virtual network function (VNF)-protection scheme. The proposed model maximizes the network's yearly availability by providing a placement decision for all 0-RAN VNFs and their backup instances. The model is solved by a column generation algorithm making it a scalable algorithm for large-scale 0-RAN deployments. Extensive computational results show that the algorithm can produce ε-optimal solutions with negligible ε (less than 0.1%) in reasonable computational times. These results significantly enlarge the exact solutions of the state-of-the-art algorithms for this problem.