Performance Analysis of CSMA/CA Broadcast Relay Network for ITS V2V Communications

The reliability of CSMA/CA vehicle-to-vehicle (V2V) communication under actual road environment suffers from fading, shadowing and hidden terminal (HT) problem. In order to improve the communication reliability, a V2V broadcast scheme with relay stations has been proposed and its effectiveness was shown by some simulations. However, the potential of the CSMA/CA broadcast relay network has not been well analyzed and optimized. In this paper, a theoretical model is proposed to analyze the performance of such network in detail. In order to fit the realistic vehicular environment, the model assumes a typical crossroad and takes into account fading, shadowing, hidden terminal problem and capture effect, as well as distances between nodes. The influence of system parameters including RF frequency band and carrier sense threshold on the reliability of the network is also studied through the analysis. The accuracy of the proposed analytical model was validated by simulations. Some suggestions to enhance the reliability of V2V communication are provided based on the results.