Joint user association and resource allocation for load balancing in RAN slicing

Abstract

In this article, we investigate the load balancing in the era of network slicing in radio access network (RAN). In our differentiated coverage RAN slicing scenario, different coverage areas of different slices have an impact on user association with base station (BS) and users’ resources obtained from BSs. Therefore, slices will limit the balance of BSs’ load. Based on this, we mainly construct a performance index to measure load balancing of RAN slicing, namely load balancing utility function. We formulate a joint optimization problem of user association and radio resource allocation for maximizing utility function. To solve this problem, we simplify and decompose it into three sub-problems, user association, slice resource allocation, and user resource allocation. We propose an iterative algorithm that uses Lagrange duality-based, Lagrange multiplier method-based, and uniform distribution methods to solve the sub-problems respectively. Finally, we obtain an approximate optimal solution with low complexity. The simulation results show that our proposed algorithm can effectively improve the load balancing utility compared with the benchmark algorithms, which means it gets the most reasonable user association and the best resource allocation.