Analytical Models for Distributed Resource Allocation in NR-V2X Mode 2

Cellular vehicle-to-everything (C-V2X) is the first standard introduced by the 3rd generation partnership project (3GPP) in its Rel. 14 to enable V2X communication. This standard is endorsed by the industries, scientists, and researchers. In C-V2X, mode 4 is designed to enable direct V2V communication via the PC-5 interface. In mode 4 vehicles select the resources which are over two-dimensional frequency and time domain for their packet transmission. These resources are scheduled based on a semi-persistent scheduling algorithm introduced by 3GPP to avoid resource contention. However, when the density of vehicles is high resolving resource contention is a major concern. To this end, 3GPP introduced NR-V2X which is the evolution of C-V2X in its Release 16. NR-V2X mode 2 is introduced as an alternative to C-V2X mode 4 for distributed resource scheduling. NR-numerologies and semi-persistent scheduling with re-evaluation mechanism is introduced by 3GPP in NR-V2X play a vital role in resolving resource contention. This paper presents first the analytical models for NR-V2X mode 2 considering the impact of NR-numerologies and re-evaluation mechanism on resource selection. The analytical models are designed considering the four transmission errors that could occur in NR-V2X mode 2. Moreover, the model validation is performed by comparing the proposed analytical models with the NR-V2X simulator implemented in ns-3. The model validation shows that the proposed analytical models are accurate.