A C-V2X Mode 4 and 802.11p-Based Resource Selection Scheme for Intraplatoon Message Delivery

This article proposes a cellular vehicle-to-everything (C-V2X) mode 4 and 802.11p-based resource selection (eInP-RS) scheme for efficient intraplatoon message delivery. The proposed eInP-RS scheme is intended to improve the delivery performance of cooperative awareness messages (CAMs) and decentralized environmental notification messages (DENMs) within a platoon. To achieve this goal, it allows each vehicle to transmit CAM and DENM packets on a C-V2X channel (CH1) and an 802.11p channel (CH2), separately, and introduces four mechanisms to enhance the standardized sensing-based semi-persistent scheduling (SPS) scheme. A contention window (CW) size adjustment mechanism is introduced to enable a vehicle to adjust its CW size according to the information it collects on CH1 in order to avoid potential packet collisions on CH2; a resource partition mechanism is introduced to divide frequency-time resources in a selection window into two sets in order for vehicles moving in opposite directions to select different resources and thus avoid potential merging collisions on CH1; an intraplatoon cooperation mechanism is introduced to enable a platoon leader to know the resource and channel occupation information of the platoon's hidden nodes on CH1 and CH2; and a packet collision detection mechanism is used to enable a nonplatoon vehicle to detect packet collisions occurring on both channels after a lane-changing maneuver to avoid potential merging collisions. Simulation results show that the proposed eInP-RS scheme outperforms the standardized sensing-based SPS scheme in terms of the CAM/DENM delivery ratio and average DENM delivery delay of a platoon vehicle.