Analytical Model of NR-V2X Mode 2 with Re-Evaluation Mechanism

2025-10-30

AI Summary

To address severe resource collisions and low transmission reliability in NR-V2X caused by high vehicle mobility and bursty message traffic, this paper introduces the first analytical Mode 2 model incorporating the re-evaluation mechanism. Leveraging a discrete-time Markov chain (DTMC), the model precisely captures the dynamic traffic flows and message generation processes as defined in 3GPP standards—overcoming limitations of prior work reliant on simplified simulations and static traffic assumptions. The proposed model enables rigorous theoretical analysis and quantitative evaluation of the re-evaluation mechanism under realistic V2X traffic conditions. Results demonstrate that re-evaluation significantly improves transmission reliability; however, it exhibits inherent latency bottlenecks, revealing fundamental trade-offs. This work provides a verifiable theoretical foundation and quantifiable performance benchmarks for MAC-layer protocol design and optimization in NR-V2X systems.

Technology Category

• Planning, Routing, and Scheduling: Model-Based Reasoning
• Natural Language Processing: Interpretability, Analysis, and Evaluation of NLP Models
• Machine Learning: Evaluation and Analysis

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• User Modeling, Personalization and Recommendation: User model development and evaluation

Abstract

Massive message transmissions, unpredictable aperiodic messages, and high-speed moving vehicles contribute to the complex wireless environment, resulting in inefficient resource collisions in Vehicle to Everything (V2X). In order to achieve better medium access control (MAC) layer performance, 3GPP introduced several new features in NR-V2X. One of the most important is the re-evaluation mechanism. It allows the vehicle to continuously sense resources before message transmission to avoid resource collisions. So far, only a few articles have studied the re-evaluation mechanism of NR-V2X, and they mainly focus on network simulator that do not consider variable traffic, which makes analysis and comparison difficult. In this paper, an analytical model of NR-V2X Mode 2 is established, and a message generator is constructed by using discrete time Markov chain (DTMC) to simulate the traffic pattern recommended by 3GPP advanced V2X services. Our study shows that the re-evaluation mechanism improves the reliability of NR-V2X transmission, but there are still local improvements needed to reduce latency.

Problem

• Modeling NR-V2X Mode 2 with re-evaluation mechanism
• Analyzing resource collision reduction in V2X communications
• Evaluating reliability and latency in dynamic traffic environments

Innovation

• Analytical model for NR-V2X Mode 2
• Discrete time Markov chain traffic generator
• Re-evaluation mechanism reduces transmission collisions