Hierarchical Slicing: A New Paradigm of Radio Resource Management for Mobile Networks

Radio access network slicing is considered to be highly challenging due to the complexity of mobile environments and the diversity of mobile services. Existing works in this area mainly decompose the radio resource management problem into slice-level resource management and user-level resource scheduling. In this paper, we propose a hierarchical three-tier slicing architecture, where an additional tier is introduced to merge the gap between the conventional two tiers in time and spatial scales. Specifically, the medium-scale tier provides inter-cell and inter-slice coordination to address short-term dynamics caused by local user mobility and traffic variations, which highly simplifies the upper and lower tiers by allowing them to focus on long-term traffic distribution and instant user demands, respectively. Thus, it allows each independent iter to apply more flexible and more efficient radio resource management methods with appropriate time and spatial scales. A proof of concept is provided to show that the proposed three-tier architecture can achieve a better tradeoff between slice isolation and slice capacity as compared to the state-of-the-art two-tier solution.