5G NR-V2X Scheduling Approaches for CPM Variable Size Traffic

2026-06-25

AI Summary

This study addresses the degraded reliability of resource scheduling in 5G NR-V2X Mode 2 under dynamic collective perception message (CPM) traffic with variable packet sizes. Leveraging real-world perception data to reconstruct CPM traffic patterns, the authors conduct system-level simulations to evaluate multiple scheduling strategies. The findings reveal that, under variable traffic loads, stability in resource allocation is more critical than instantaneous optimization. Specifically, semi-persistent scheduling (SPS) combined with a padding mechanism delivers robust and reliable transmission performance. While modulation and coding scheme (MCS) adaptation improves average reception rates, it introduces significant reliability fluctuations. In contrast, dynamic scheduling and aggressive reselection lead to substantially higher collision rates due to frequent resource reallocations. Based on these insights, this work establishes practical design guidelines for NR-V2X scheduling tailored to real-world deployment scenarios.

Abstract

Collective perception messages (CPMs) introduce significant packet size variability due to dynamic object inclusion and periodic security overhead. While 5G NR-V2X Mode 2 typically employs semi-persistent scheduling (SPS) designed for periodic traffic with relatively stable packet sizes, the impact of realistic CPM-driven size fluctuations on distributed resource allocation remains insufficiently understood. This paper presents a comparative system-level evaluation of NR-V2X Mode 2 scheduling strategies under variable-size CPM traffic reconstructed from real-world perception datasets. We analyze dynamic scheduling and multiple SPS-based approaches, including padding-based allocation, aggressive size-driven reselection, and modulation and coding scheme (MCS) adaptation. Results show that packet size variability can significantly degrade reliability when scheduling stability is compromised. In particular, dynamic scheduling and aggressive reselection increase collision probability due to frequent resource reallocations. In contrast, SPS with padding converges to a stable resource allocation and provides robust performance, while MCS adaptation achieves the highest average packet reception ratio but with uneven reliability across packet types. The findings demonstrate that, under realistic CPM traffic, stability of resource usage is more critical than instantaneous load optimization, and provide design guidelines for CPS deployment over NR-V2X Mode 2.

Problem

• NR-V2X
• CPM
• variable-size traffic
• resource allocation
• scheduling

Innovation

• NR-V2X Mode 2
• Collective Perception Messages (CPMs)
• semi-persistent scheduling (SPS)
• packet size variability
• MCS adaptation