# A Design of a Lightweight In-Vehicle Edge Gateway for the Self-Diagnosis of an Autonomous Vehicle
## 2 Related Works
### Vehicle Protocol  
The CAN (bus arbitration mechanism) [18] protocol is used as standard in most vehicles today. However, it cannot handle many data. Both MOST and FlexRay communication mechanisms have been designed in consideration of the communication speed of these CAN buses and the limitation of data communication load [19]. The following is a related study of the vehicle protocol. [PERSON] et al. [20] introduced a FlexRay-CAN gateway that uses node mapping. It is possible to solve the problem of the gateway of the vehicle such as the ID change of the message mapping-based gateway or the software complexity. [PERSON] et al. [21] adopted a new way to achieve the design and the implementation of the FlexRay Controller which consists of the translation of the (Specification and Description Language) SDL diagrams into State Flow diagrams. With these diagrams, we generate the VHDL code of the controller which will be implemented in an FPGA to create the hardware chip for FlexRay. The transmission reliability and the slot utilization are defined for FlexRay network, and their quantitative calculating formulas are deduced. To ensure reliable network transmission and maximize bandwidth utilization of network, frame packing of FlexRay is formulated as generalized integer linear programming, and an optimized model is presented [22]. [PERSON] et al. [23] proposed an effective two-level redundancy approach for safety-critical FlexRay network systems. The proposed approach demonstrates how to employ the backup nodes, mirrored tasks and task migration to sustain the operation of system when ECUs fail. We then perform the redundancy analysis and develop the analytical reliability models for the assessment of fault-tolerant FlexRay network systems in early design phase. [PERSON] et al. [24] considered the problem of mapping an application task graph onto a FlexRay-based distributed hardware platform, to meet security and deadline requirements while minimizing the number of hardware coprocessors needed in the system. We present a Mixed Integer Linear Programming (MILP) formulation, a divide-and-conquer heuristic algorithm, and a Simulated Annealing algorithm. [PERSON] et al. [25] proposed a FlexRay-based software reprogramming optimization, and we analyze the performance of FlexRay and CAN FD software reprogramming. To achieve this, we perform a theoretical analysis on the software reprogramming times of the protocol, and we compare the performance of the software reprogramming optimized FlexRay and CAN FD. [PERSON] et al. [26] focused on the development of FlexRay drivers and Simulink Block set implementations to validate performance and design, and to provide innovative capabilities for today and tomorrow to distributed systems in automotive applications. The proposed block set is dedicated for the SAE (Society of Automotive Engineers) application. The SAE benchmark model is normally connected by the CAN bus, but we extend it to the FlexRay bus. In [27], they also proposed a vehicle Simulink block set model. The proposed block set corresponds to the Society of Automotive Engineers SAE benchmark model which is normally connected by the CAN bus, but we extend it to the FlexRay bus. [PERSON] et al. [28] outlined improvements to FlexRay and Ethernet in automotive communications networks. Protocols need to improve the protocol to meet the needs of tomorrow's automotive networks, but Ethernet can speed development and expand faster. [PERSON] et al. [29] showed how to use DDS over an Ethernet network and proposed a SAE benchmark as a test application. The main goal is to calculate the worst-case response time (WCRT) based on the scheduling model and the use it as a metric to evaluate the DDS real-time QoS (Quality of Service). The results obtained using Ethernet are compared with those found using FlexRay. [PERSON] et al. [30] proposed a virtual communication layer for time-triggered networks, enabling a policy-based message scheduling as well as preemption which in turn simplifies real-time verification.