On the Impact of priority-based MAC Layer Scheduling in 5G V2N multi-application Scenarios

The automotive market's ongoing shift towards connected and automated vehicles has enabled a multitude of new use cases enabled by Cellular Vehicle-to-Everything (C-V2X) communications. With the hyperconnectivity enabled by 5G, many new applications utilize Vehicle-to-Network (V2N) communications to deliver services with many objectives such as infotainment, advanced driving, etc. These different applications come with different configurations and Quality-of-Service (QoS) requirements that should be satisfied by the network. A base station could use the scheduler on the Media Access Control (MAC) layer to divide the available radio resources among all connected vehicles to satisfy these various requirements. In this paper, we focus on such MAC layer schedulers located in 5G gNodeBs. The scheduler has to handle four different application types of several connected vehicles simultaneously, considering new data packets and Hybrid Automatic Repeat reQuest (HARQ) retransmissions. For the prioritization of the different parallel services, we consider different approaches which all determine a scheduling priority differently and compare its impact on the application layer performance via network simulation in a real traffic scenario. One main part of our study is to integrate the 5G QoS model into the simulator to be able to use standardized values from 3GPP specification as a scheduling priority. We use the OMNeT++ framework 5G-Sim-V2I/N for this investigation. We present a detailed study on the performance of each of the various prioritization approaches and suggest a path forward on how to optimize the scheduler performance.