Analysis of periodic broadcast message for DSRC systems under high-density vehicle environments

Recently, many applications for co-operative Intelligent Transportation System (C-ITS) using wireless vehicle communication technology such as DSRC have been developed to improve traffic problems and provide user convenience. Above all, broadcast message sets such as CAM and DENM are very useful for vehicle safety. However, V2X systems must design system parameters in highly congested traffic conditions, especially to ensure robust communication channels while avoiding packet collisions. This paper analyzes the proper transmit power control to maintain channel load under maximum channel capacity. From the obtained system parameters, the packet delivery ratio and the mean delay are analyzed as system performance for periodic broadcast messages. In addition, the analysis for the physical transmission mode and the contention window size is performed to satisfy the packet collision rate of 1% in the given number of vehicles and transmission packet size.