Resource Scheduling under Knock-Out Congestion Control in New Radio (NR) Sidelink Mode 2

Kyeongnam Park, Hyogon Kim

Research output: Chapter in Book/Report/Conference proceedingConference contribution


For resource scheduling in New Radio (NR) Sidelink Mode 2, the 3GPP Release 16 eliminated a step from the Release 14 resource selection algorithm, i.e., Received Signal Strength Indicator (RSSI)-based sorting of candidate resources. However, we show that this change can have detrimental effects when combined with congestion control. Packet knock-outs on the access layer is explicitly suggested in standards and a facilities layer packet knock-out (Cooperative Awareness Message (CAM) generation rule) has been established as a standard for congestion control. The absence of the RSSI-based candidate sorting for resource selection makes it difficult to utilize the residual quasi-periodicity after packet knock-outs, and increases packet collisions. We demonstrate that in case of the CAM generation rule, the reintroduction of the RSSI-based sorting step increases the packet reception ratio (PRR) within 300 m of the transmitter by more than 5% compared to the default Release 16 algorithm. It contrasts with a surprising finding that the new grant breaking feature for aperiodic traffic underperforms the default Release 16 scheduling algorithm in the same conditions. The findings suggest that the value of the RSSI-based sorting of candidate resources should be reevaluated in NR vehicle-to-everything (V2X) congestion control.

Original languageEnglish
Title of host publication2022 IEEE 96th Vehicular Technology Conference, VTC 2022-Fall 2022 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781665454681
Publication statusPublished - 2022
Event96th IEEE Vehicular Technology Conference, VTC 2022-Fall 2022 - London, United Kingdom
Duration: 2022 Sept 262022 Sept 29

Publication series

NameIEEE Vehicular Technology Conference
ISSN (Print)1550-2252


Conference96th IEEE Vehicular Technology Conference, VTC 2022-Fall 2022
Country/TerritoryUnited Kingdom

Bibliographical note

Publisher Copyright:
© 2022 IEEE.


  • NR V2X
  • Sidelink Mode 2
  • knock-out congestion control
  • quasi-periodic traffic
  • resource scheduling

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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