the latency of LLC traffic. The latency is measured from the time when the LLC payload arrives at the base station until it is correctly received by the terminals, including the aggregated latency from scheduling, frame alignment, transmission time, and TX/RX processing delays. The ccdf shows that even under the considered full load conditions, the perfor- mance for the LLC traffic fulfills the challenging URLLC target of 1 ms latency with an Packets that go through in the initial transmission Packets requiring HARQ retransmission URLLC latency [ms] Figure 10.55 Complementary cumulative distribution function of the LLC packet latency. 10.8 Packet Scheduling Algorithms outage of only 0.001% (=10-5). Hence, the preemptive scheduling scheme fulfills its pur- pose: the ability to efficiently schedule the LLC traffic in line with its challenging latency and reliability constraints, while still having efficient scheduling of mobile broadband traffic without the need for pre-reservation of radio resources for sporadic LLC traffic. 10.8.2 Mini-Slot Scheduling The mini-slot allows data transmission using just a part of the slot. Mini-slot allocations can improve the delay and throughput performance of users with small amounts of data. Using mini-slots for UEs with large amounts of data in their buffer will hurt system per- formance due to the additional control channel (PDCCH) overhead. Mini-slots can also result in fragmentation and inefficient use of resources, as all symbols may not be usable. The packet scheduler can decide how to share the resources and how to optimally uti- lize mini-slots. This section addresses these trade-offs and presents a scheme that can optimally use the flexibility of mini-slots to improve the performance of mobile broad- band traffic. The objective is to dynamically determine the optimum mini-slot duration on a per-slot and per-user basis, which means determining the set of users which would benefit from mini-slot allocation and the optimum duration of the mini-slot to be used for each such