# Analysis of 5G Channel Access for Collaboration with TSN Concluding at a 5G Scheduling Mechanism
## 7 Evaluation  
The purpose of this evaluation is to validate the traffic shaping behavior of a scheduler using dynamic LCP (dLCP) for multiple TSN streams over a single UE. Therefore, we set up a system-level simulation of the NG-RAN using the Matlab 5G Toolbox. It contains Physical Layer (PHY), MAC, Radio Link Control (RLC), and an application layer. We configured four Radio Bearers for the connection of one UE and a gNB in the downlink direction. Three Radio Bearers carry TSN traffic classes. The packets for the three TSN  
Figure 4: Example of the translation of a GCL into LCP vectors \(\tilde{c}_{ij}\). Figure 3: Bridge representation of a 5 GS. streams are generated by the application layer with a periodicity of 10 ms, while the packets for the fourth Radio Bearer are generated every 1 ms, i.e., every slot with a SCS of 15 kHz. Radio Bearer 4 is deployed in order to simulate the influence of additional Best Effort traffic using the remaining channel resources after the allocation of resources to the highly prioritized traffic. Across several series, measurements for the passed time between the sending and receiving of messages were captured and analyzed. This was performed for the dLCP in order to evaluate whether the requirements of deterministic and time-critical communication for TSN traffic were fulfilled. Additionally, a comparison with the static approach is provided here to demonstrate the difference in effect and prove that the proposed mechanism and our implementation operate as intended. With dLCP deactivated, the three Logical Channels carrying TSN traffic are configured with the same Logical Channel Priority, and the Logical Channel carrying Best Effort traffic is configured with a lower Priority. The Prioritized Bit Rate is set to infinity, meaning that a Logical Channel being served is granted enough resources to send all of its remaining data. When dLCP is activated, the Logical Channel Priorities of the TSN streams are updated at every TTI, e.g., every slot, enforcing a GCL of the periodicity of 10 ms. The GCL contains time slots for each of the three TSN traffic classes, covering three TTIs, respectively. In order to isolate the consideration of the traffic shaping behavior from the influence of retransmissions and additional overhead, the RLC entities run in Unacknowledged Mode and the simulated Block Error Rate in the Physical Layer is set to 0. The variation of the channel quality is considered by varying the CQI for every Resource Block once in every slot by a random value in the range of \(\pm 5\). The channel quality has an impact on the applied MCS, and therefore on the available Transport Block Size at every TTI. Over a period of 100 NG-RAN frames, i.e., 1000 TTIs, measurements are made for the slot (TTI) in which every packet of each TSN stream is received completely. Figures 5 and 6 show the accumulated and normalized amounts of packets received in each slot. Figures 7 and 8 show the slots for the arrival of each packet with and without dLCP, respectively. In the latter case, the interval of ten slots is divided into three different slots, in which only a specific TSN traffic class is allowed to access the resources of a Transport Block. In order to evaluate the impact of dLCP on the determinism of parallel TSN streams, we consider the jitter of the packet arrival times in the UE. The amount of elapsed TTIs between the reception of two consecutive packets is measured. This results in a data series in which the deviation of a packet arriving from the regular transmission framework of 10 ms corresponds to a peak in the data. Therefore, the mean of the standard deviations of the data series can be taken as a measure of the determinism of the packet transmission, with lower values corresponding to a higher degree of determinism. This value is computed for the use of dLCP and the use of normal (static) LCP, respectively, for different packet sizes of the TSN streams. Additionally, the maximum amount of grantable Resource Blocks is varied.