IRS-Assisted Weighted Sum-Rate Maximization Semi-persistent Scheduling in NR-V2X

Abstract

A well-known issue in NR-V2X Mode 2 is the packet collision that results from two or more vehicles selecting the same resource block (RB) for transmission through distributed competition in the scenarios without a centralized coordinator. Consequently, it may lead to serious safety problems if the collided RB is used to send safety information by the vehicles. In this paper, we propose an intelligent reflecting surface (IRS)-assisted semi-persistent scheduling (SPS) scheme to resolve the RB conflicts by utilizing the IRS to enhance the signal reflection sent from the vehicle selected to occupy the RB. To this end, we propose a weighted sum-rate maximization model to jointly determine the vehicle selection and the IRS reflection control. In order to achieve a trade-off between the efficiency of RBs and the coordination of contending vehicles, we conceive an evaluation method to assess the transmission rate weights among the contending vehicles, which considering both wireless resource occupation and services urgency. In addition, we develop a joint conflict resolution and IRS reflection control(JCRIRC) algorithm based on DDPG to approximate the optimal solution. Simulation results verify the improvement of RB utilization and take wireless resource occupation and services urgency into account.