Experimental analysis of CCA threshold adjusting for vehicle EWM transmission in V-CPS

摘要

Vehicular cyber-physical system (V-CPS) offers the potential to significantly improve the safety, comfort and entertainment to motorists. The topic of emergency warning messages (EWMs) transmission is still most import for V-CPS because of the thousands of lives taken by traffic accident. The EWM dissemination is expected to inform the related vehicles in time. This paper proposed a new EWM dissemination mechanism based on the clear channel assessment (CCA(th)) threshold adjusting method to reduce the transmission delay by shorten the sensing time for idle channel. Experimental results obtained from the testbed - EyeNet - showed that the proposed mechanism employing an appropriate CCA(th) setting can shorten the transmission delay with 12 ms, and guarantee a relative high successful dissemination rate about 60%.