Crash Warning for Intersection and Head-on Car Collision in Vehicle-to-Vehicle Communication

This paper investigates performance of the IEEE 802.11p based vehicle-to-vehicle communication for car crash warning to avoid head-on car crash and car crash at a road intersection. It is important in a car crash warning application that each vehicle receives a sufficient amount of information (i.e., a sufficient number of frames) in time to avoid a potential crash. When vehicles transmit a large number of frames, as CSMA/CA used in IEEE 802.11p creates a large number of collisions between frames, this results in low throughout of the frames to receiving vehicles. This paper uses the following two measures to evaluate the performance and suitability of IEEE 802.11p for car crash warning communication; the number of frames that each vehicle receives per second, and the length of time duration in which the number of frames that each vehicle receives per second exceeds the predetermined threshold. In obtaining these measures, this paper considers realistic scenarios of capture effect in CSMA/CA, unlike the existing studies. We further consider scenarios of avoiding head-on car crash and car crash at a road intersection, because car crash at a road intersection occurs often, and head-on car crash presents one of the most difficult communication conditions due to the additive effect of the speed of two vehicles approach each other. Our simulation results show the following. For head-on car crash scenarios, when there are up to approximately 150 vehicles in the communication range of a vehicle, the vehicle can successfully receive at least the predetermined number of frames per second. For car crash at a road intersection, the number of cars in vehicle's communication range increases to approximately 200 in order to successfully receive at least the pre-determined number of frames per second. Our simulation results also show that the length of time duration in which the number of frames that each vehicle receives per second exceeds the predetermined threshold is much longer with car crash at a road intersection than with head-on car crash.