An Improved SB-SPS Scheme with Low Transmission Delay for Relay Transmission in Vehicle Platooning with C-V2X Sidelink Communication

C-V2X (Cellular-Vehicle to Everything) is a promising communication technology for achieving vehicle platooning. C-V2X standardizes sidelink communication for V2V (Vehicle-to-Vehicle) direct transmission and it employs the SB-SPS (Sensing Based Semi Persistent Scheduling) scheme for its resource management. For the vehicle platooning, periodic information sharing for a lead vehicle is essential among the vehicles within the entire platoon, and relay transmission employing sidelink communication is considered as one of promising sharing means. However, the SB-SPS scheme is originally designed for broadcast communications, and then, for relay transmissions in the platoon, it may cause large transmission delay from the lead vehicle to the tail end one due to forwarding delay at intermediate relay vehicles. This work clarifies the impact of the SB-SPS scheme on the performance for relay transmissions in vehicle platooning with C-V2X sidelink communication, and proposes an improved SB-SPS scheme to reduce the transmission delay. The performance evaluation through computer simulation demonstrates the effectiveness of the proposed scheme.