Research On Scheduling Optimization Approach And Lightweight Message Authentication Protocol For Time-triggered Network-oriented Automotive Control Systems

With the further development in sensors,electronics,computer and communications technology,and the increasing demand of people's consumption,the intelligence and interconnection has becoming an inevitable trend in the development of automotive control systems.The current car is equipped with advanced sensors,controllers,actuators and other in-vehicle devices and integrates network and communication technology to achieve a variety of advanced driver assistance,comfort and entertainment functions,and will eventually to realize automatic drive.However,as the intelligence and interconnection are facilitating safe,energy-efficient,comfortable and efficient driving,they also bring unprecedented challenges to the vehicle control system design.On the one hand,with the improvement of the intelligent level of the automotive control systems,the amount and complexity of the control applications within the systems,the assigned task density on the single node and the signal density on the communication network are significantly increased,thus the system scheduling is more difficult to design.As for the automotive control systems,the correctness of their control behavior depends not only on the logical results of the calculations,but also on the physical time at which the results are producted.If the time at which the result is produced can not meet the time requirements of the control application,the results may be useless and even cause very serious consequences.Therefore,in order to satisfy the time constraints of multiple concurrent real-time control applications and the constraints of network communication protocols in the system,an optimized system-level scheduling becomes a necessary guarantee to ensure the normal operation of system functions.On the other hand,with the increasing interconnection of the automotive control systems with the physical environment,the surrounding infrastructure,the cloud database and other embedded systems,the possibility that the system will be attacked is increasing,thus the information security becomes a pressing problem in the system design.The internal networks of automotive control systems are currently designed without information security considerations.Once a node of the system is attacked by an attacker through any network connection interface,the attacker can easily inject a fake message or replay the message into the security critical real-time control network,thereby breaking the normal operation of the system and leading to the system failures.In order to avoid such attacks,it is urgent and necessary to design a message authentication mechanism for the internal communication network of the automotive control systems,taking into account the tight resource constraints of these systems,such as limited bandwidth,computing,storage resources,and the strict performance requirements,such as high real-time,high scalability and high security.This thesis focuses on the time-triggered network-oriented automotive control systems to research from two aspects of scheduling optimization and lightweight message authentication.The major contributions of this thesis include:Scheduling Optimization:1.Scheduling Optimization: This thesis studies the scheduling optimization problems of time-triggered automotive control systems communicating over the Flex Ray and the TTEthernet networks,that includes not only signal to frame packing,but also frame schedule(frame to slot assignment),task schedule and the synchronization of signal and task scheduling considering the constraints of ene-to-end delays of the applications,the precedence between tasks and signals and network communication protocol.In order to solve the above problems,this thesis proposes the corresponding Mixed-Integer Linear Programming(MILP)scheduling optimization method,respectively.The objective of the proposed MILP method is to improve the timing performance of the applications or the extensibility of the network.Experiments of an X-by-wire system on actual prototype vehicles and multiple synthetic test cases demonstrate the efficiency and effectiveness of the proposed method under a variety of scenarios.2.Lightweight Message Authentication: This thesis first proposes a lightweight message authentication protocol for time-triggered network-oriented automotive control systems.The proposed protocol is built on delayed exposure of multilevel hierarchical one-way chains,which provides an appropriate trade-off between security,real-time performance and resource constraints.In addition,this thesis proposes an optimal approach for the implementation of the proposed protocol on the time-triggered automotive control systems,to support cost-effective performance while satisfying all other design constraints.Extensive performance evaluations were conducted to demonstrate the feasibility,light weight and scalability of the proposed authentication protocol.3.Co-scheduling Optimization of the Control Applications and the Message Authentication Applications: In addition,the tight resource constraints and strict performance requirements of the automotive control systems make it difficult or even impossible to add the security mechanism after completing the schedule design.It is therefore important to address security together with other design constraints in designing the system scheduling,in order to ensure the original control function of the system will not be hindered and can achieve the desired performance after integrating the message authentication protocol to the systems.This thesis studies the co-scheduling optimization problem of the control applications and the message authentication applications for time-triggered automotive systems communicating over the Flex Ray bus and the TTEthernet,to improve the quality of service of the systems that support message authentication mechanism.This thesis proposes the corresponding MILP scheduling optimization method to solve the above co-scheduling optimization problem,respectively.The proposed MILP method determines the packing of the control application and message authentication protocol-related signals,the scheduling of the frames on the network,and the scheduling of the control application and message authentication protocol-related tasks on their respective nodes,considering the constraints of ene-to-end delays of the applications,the precedence between tasks and signals,network communication protocol and message authentication protocol.The objective of the proposed MILP method is still to improve the timing performance of the applications or the extensibility of the network.The experiment results show the efficiency and effectiveness of the proposed method as well as the feasibility and light weight of the proposed authentication protocol.To the best of our knowledge,this is the first work to address the co-scheduling optimization problem of the control applications and security-related applications for time-triggered automotive systems.