A ladder cca threshold selection mechanism for multi-hop vehicle EWM transmission

作者：Han Qingwen^*; Zhang Zhe; Zeng Lingqiu; Ye Lei; Zhu Yingxiang

来源：Journal of Communications, 2015, 10(1): 33-42.

DOI：10.12720/jcm.10.1.33-42

• Clear channel assessment
• Delivery ratio
• Emergency warnings
• Inter vehicle communications
• Threshold selection

Emergency warning message (EWM) transmission insurance is one of the most interesting topics for Vehicular Cyber-physical System (V-CPS) application. A relatively low transmission requirement should improve EWM’s real-time delivery, and however, decrease reliability of packet delivery by its corresponding burst converge-cast, especially under multi-hop condition. In this paper, based on a series experiments, a clear channel assessment (CCA) threshold ladder selection method is proposed to ensure both real-time and reliability for EWM transmission. The experimental results show that the threshold adjusting method has a positive effect on the delivery rate. With an appropriately diminishing clear channel assessment threshold related to the packet hops, the global dissemination successful rate can be up to 73.5%, and more than 90% of the 1-hop nodes can receive the correct packet. The experiment results provide a practicable method to improve EWM dissemination performance.

• 出版日期2015