RAN Slicing Performance Tradeoffs: Timing Versus Throughput Requirements

The coexistence of diverse services with heterogeneous requirements is a fundamental feature of 5G. This necessitates efficient Radio Access Network (RAN) slicing, defined as sharing of the wireless resources among diverse services while guaranteeing their throughput, timing, and/or reliability requirements. In this paper, we investigate RAN slicing for an uplink scenario in the form of multiple access schemes for two user types: (1) broadband users with throughput requirements and (2) intermittently active users with timing requirements, expressed as either Latency-Reliability (LR) or Peak Age of Information (PAoI). Broadband users transmit data continuously, hence, are allocated non-overlapping parts of the spectrum. We evaluate the trade-offs between the achievable throughput of a broadband user and the timing requirements of an intermittent user under Orthogonal Multiple Access (OMA) and Non-Orthogonal Multiple Access (NOMA), considering capture. Our analysis shows that NOMA, in combination with packet-level coding, is a superior strategy in most cases for both LR and PAoI, achieving a similar LR with only a slight 2% decrease in throughput with respect to the case where an independent channel is allocated to each user. The latter solution leads to the upper bound in performance but requires double the amount of resources than the considered OMA and NOMA schemes. However, there are extreme cases where OMA achieves a slightly greater throughput than NOMA at the expense of an increased PAoI.