[论文解读] Platoon Stability and Safety Analysis of Cooperative Adaptive Cruise Control under Wireless Rician Fading Channels and Jamming Attacks

Amir Alipour-Fanid, Monireh Dabaghchian+1 more|arXiv (Cornell University)|Oct 23, 2017

Traffic control and management参考文献 25被引用 10

一句话总结

本文在瑞利衰落信道和干扰攻击条件下，对合作自适应巡航控制（CACC）系统中无线通信可靠性与车辆车队动力学之间的网络物理耦合关系进行了建模。通过时域指标分析车队稳定性，并基于车辆间距离可达性评估安全性，结果表明：当干扰攻击目标为第二辆车且主车减速时，干扰最具破坏性。

ABSTRACT

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.

研究动机与目标

• 对CACC车队中无线信道可靠性（瑞利衰落、干扰）与物理车辆状态（车头间距）之间的双向耦合关系进行建模。
• 利用时域车队稳定性指标，评估无线信道劣化对车队稳定性的影响。
• 通过计算在干扰攻击下车头间距轨迹的上下界，评估车队安全性。
• 识别出对车队造成最大不稳定化的攻击者最优位置和时机。
• 研究干扰效果如何随主车减速和车辆发射功率设置而变化。

提出的方法

• 将车头间距动力学建模为状态相关形式，纳入瑞利衰落对信号强度和分组投递率的影响。
• 采用时域车队稳定性定义，量化信道衰落和干扰对车队稳定性的影响。
• 应用可达性分析，计算在干扰和衰落条件下车头间距轨迹的上下界。
• 通过模拟10,000条轨迹，评估不同干扰策略（连续与部分）下的安全性和稳定性。
• 采用速度相关间距策略，基于主车减速情况确定最优攻击时机。
• 在频域中使用非线性规划推导最小车间距时间，并在时域中进行验证。

实验结果

研究问题

• RQ1 无线信道中的瑞利衰落如何影响CACC车队的车队稳定性和安全性？
• RQ2 干扰器在CACC车队中何处部署可最有效地造成不稳定？
• RQ3 干扰攻击的时机——尤其是主车减速期间——如何影响车头间距轨迹和安全性？
• RQ4 在干扰和衰落条件下，车头间距轨迹的上下界是什么？
• RQ5 车辆和干扰器的发射功率水平如何影响平均车队稳定性？

主要发现

• 信道衰落会降低CACC系统性能，尤其在车头间距控制和车队稳定性方面。
• 当攻击者位于车队第二辆车正上方时，车队对干扰最为脆弱。
• 当主车减速时，干扰攻击对车队的破坏性最强，因为此时发生不安全车头间距的可能性更高。
• 部分定时干扰攻击——仅在主车减速期间激活——会产生更密集且更低的车头间距轨迹，相较于连续干扰，安全风险更高。
• 在干扰条件下，大量模拟轨迹达到零车头间距，表明存在不安全状态。
• 所提出的可达性分析成功计算出车头间距轨迹的紧密上下界，实现了在不确定性条件下的安全性验证。