On the reliability of DSRC safety applications: A case of jamming

Dedicated Short Range Communication (DSRC) is the wireless communication protocol of safety applications in Intelligent Transportation Systems (ITS) using Vehicular ad hoc Networks (VANET). Due to the criticality of the ITS the reliability of its safety applications is of great concern. Much research has been dedicated to reliable message exchange in VANET, mainly focusing on the physical and Media Access Control (MAC) layers. In contrast, our research considers reliability from the safety application point of view, as it is adversely affected by malicious behavior, thus shedding light on application layer reliability. Specifically, the wireless communication shared medium can be used by jammers to launch Wireless Denial of Service (WDoS) attacks. This has great implications for Basic Safety Message (BSM), which is the most important message for safety applications as defined in the SAE J2735 Message Set Dictionary Standard. In this paper we study the impact of different jamming types, constant, random, and intelligent, on the reliability of BSM message exchanges. For the research we selected the Forward Collision Warning (FCW), which is one of the identified critical safety applications by the standard. We introduce survivability mechanisms, utilizing the concept of dissimilarity and redundancy, to increase reliability of the application. These mechanisms are strictly compliant with existing standards, and thus do not require any mechanisms outside of the standards. The impact of the different jamming types and the effectiveness of our solutions on the application reliability are demonstrated.