The Impact of RAN Slice Bandwidth Subpartitioning on Slice Performance

Network slicing in 5G RAN enables building logical networks on top of physical infrastructure. In case of RAN spectrum resources are divided into small bandwidth parts then, the network function in core network, namely Network Slice Admission Control Function (NSACF) enables to limit the count of user equipments (UE) and packet data unit (PDU) sessions in a slice. This paper presents negative results and a practical analysis of how many UEs and PDU sessions can be allowed to use if available bandwidth is fixed and tries to evaluate the optimal count of subslices at this bandwidth. In case of slice resource overutilization there are 2 options: increase resources or move UEs to another slice. In this paper, the feasibility of the other option is evaluated in case of fixed overall bandwidth where resource increase is not possible. Results show that infrastructure can afford as few slices as possible and slicing does not help if theoretical capacity is exceeded.