  Cooperative Adaptive Cruise Control (CACC) is considered as a key enabling
technology to automatically regulate the inter-vehicle distances in a vehicle
platoon to improve traffic efficiency while maintaining safety. Although the
wireless communication and physical processes in the existing CACC systems are
integrated in one control framework, the coupling between wireless
communication reliability and system states is not well modeled. Furthermore,
the research on the impact of jamming attacks on the system stability and
safety is largely open. In this paper, we conduct a comprehensive analysis on
the stability and safety of the platoon under the wireless Rician fading
channel model and jamming attacks. The effect of Rician fading and jamming on
the communication reliability is incorporated in the modeling of string
dynamics such that it captures its state dependency. Time-domain definition of
string stability is utilized to delineate the impact of Rician fading and
jamming on the CACC system's functionality and string stability. Attacker's
possible locations at which it can destabilize the string is further studied
based on the proposed model. From the safety perspective, reachable states
(i.e., inter-vehicle distances) of the CACC system under unreliable wireless
fading channels and jamming attacks is studied. Safety verification is
investigated by examining the inter-vehicle distance trajectories. We propose a
methodology to compute the upper and lower bounds of the trajectories of
inter-vehicle distances between the lead vehicle and its follower. We conduct
extensive simulations to evaluate the system stability and safety under jamming
attacks in different scenarios. We identify that channel fading can degrade the
performance of the CACC system, and the platoon's safety is highly sensitive to
jamming attacks.
