Comparative Analysis of DSRC and LTE-V2X PC5 Mode 4 with SAE Congestion Control

In vehicle-to-everything (V2X) communications, ensuring the scalability is one of the most important aspects of V2X safety applications. This paper analyzes and compares the scalability performance of dedicated short-range communication (DSRC) based on IEEE 802.11p and 3GPP Rel-14 LTE-V2X PC5 mode 4 (i.e., direct communication mode without the help of base stations) in transmitting the Basic Safety Messages using SAE congestion control mechanisms in freeway scenarios with up to 4000 vehicles over a 5-km road. Simulation results show that for V2V distances below 300 m, DSRC over 10-MHz bandwidth is comparable with LTE-V2X over 20-MHz bandwidth with HARQ retransmission. Also, we reveal that LTE-V2X has a consecutive packet loss issue due to its semi-persistent scheduling mechanism. The results show that the use of a wider bandwidth and packet retransmission in LTE-V2X can partly mitigate a consecutive packet loss issue.