Uplink Scheduling for Mixed Grant-Based eMBB and Grant-Free URLLC Traffic in 5G Networks

Scheduling in 5G networks is a challenging task due to the heterogeneous Quality of Service (QoS) requirements of traffic sources. In this paper, we consider the problem of uplink scheduling in 5G networks for mixed traffic that includes Ultra-Reliable Low Latency Communications (URLLC) devices and enhanced Mobile Broad-Band (eMBB) users. For this purpose, a mathematical model for Grant Free (GF) services is derived for the k-repetitions Hybrid Automatic Repeat reQuest (HARQ). We formulate the scheduling problem as a mixed-integer non-linear programming optimization problem. We introduce a complete system model that includes grant-free and grant-based subsystems. We then introduce our proposed solution to the scheduling problem that addresses the two traffic types. Different scheduling techniques are then compared and a performance upper bound is added as a reference. The results show that the proposed technique provides near-optimal results and outperforms other scheduling techniques with a significant complexity reduction.