Echelon-Based Collaborative Resource Allocation for Platoon Communication in C-V2X Networks

Vehicular platoon communication demands high reliability and low latency to ensure safe and coordinated operations. However, the semi-persistent scheduling (SPS) protocol in Cellular Vehicle-to-Everything (C–V2X) Mode 4 often results in persistent packet collisions in resource contention scenarios, greatly undermining the stability of the platoon. This article proposes a echelon-based collaborative resource allocation (ECRA) protocol that conceptualizes the platoon structure as a three-tier communication hierarchy and implements refined resource management strategies. ECRA introduces four mechanisms to enhance the reliability of platoon communication. Specifically, a vehicle role-aware resource evaluation mechanism achieves differentiated assessment and allocation of resource quality by considering the functional importance of vehicles within the platoon. A hybrid error classification mechanism effectively differentiates communication errors within the platoon by integrating deterministic decision making with fuzzy logic. A echelon-based error response mechanism provides customized resource selection strategies and error response mechanisms for vehicles of different roles, ensuring efficient allocation of communication resources according to importance. A echelon-based waiting window mechanism dynamically optimizes the detection frequency based on vehicle roles, thereby balancing real-time requirements with system overhead. Finally, a theoretical model of packet collision probability and average delay is developed to quantify improvements in reliability and latency. Simulation results demonstrate that the proposed ECRA enhances platoon communication reliability and reduces latency more effectively than traditional SPS and other existing solutions. In particular, ECRA exhibits superior robustness in dynamic environments, especially under high-density and complex interference conditions.