Joint Wireless Access-Backhaul Network Slicing and Content Caching Optimization

Network slicing is a novel paradigm shift in the fifth-generation (5G) virtualized wireless network design, which enables to reduce the operation cost (OPEX), improve network resource utilization efficiency, and speed up new service deployment. Wireless backhauling has been also recognized as an important and promising 5G network element to further ease network implementation and reduce OPEX. Meanwhile, intelligent content caching, which places popular contents at the network edge, can help relieve the backhaul congestion and improve user quality of service (QoS). Joint content caching and network slicing in the wireless backhaul based 5G networks, however, present great potential and challenges. In this paper, we study the joint resource allocation and content caching problem which aims to efficiently orchestrate the resource management in both wireless access and backhaul networks and caching storage repository. Our design objective is to minimize the maximum content request outage probability experienced by users associated with different cells and from different mobile virtual network operators (MVNOs). The underlying optimization problem is a mixed-integer non-linear program (MINLP), which is difficult to tackle. We propose a bisection-search based algorithm that iteratively optimizes the resource allocation and content caching strategy. The efficacy of our proposed framework is confirmed by extensive numerical results, which shows the significant reduction of request outage probability compared to other benchmark algorithms.