Leveraging 3GPP Features and Optimization Techniques for 5G NR-V2X Resource Allocation:A Survey

Cellular Vehicle-to-everything (C-V2X) communication is critical for Intelligent Transportation Systems (ITS), facilitating information exchange among road users and infrastructure. Since its first introduction in rel-15 by 3GPP, 5G NR-V2X features have continued to evolve, aiming to support increasingly advanced V2X services. Addressing diverse service requirements, spectrum scarcity, dynamic vehicular environments, and radio interference necessitates efficient resource allocation strategies for the 5G NR-V2X system. However, dealing with resource allocation problems involving various conflicting objectives and constraints while accomplishing the Quality of Services (QoS) requirements of the V2X system remains a challenging issue. In this direction, this survey examines state-of-the-art resource allocation strategies for 5G NR-V2X, focusing on 3GPP features associated with V2X communication and their implications, along with optimization techniques employed in designing resource allocation strategies. Specifically, we present the benefits and challenges of each 3GPP feature and optimization technique, and their application to communication and computing resource allocation problems. Finally, we discuss issues tied to 3GPP features and optimization techniques, then highlight future research opportunities for efficient 5G NR-V2X resource allocation.