Design of Fault-Tolerant Task Processing Model and Implementation of Inter-Module Communication Interfaces in a Connected Car Environment

The objective of the IITP research project conducted in the laboratory is to reduce job latency by using smartphones as edge nodes. My role was to design a fault-tolerant task processing model using a RSU and to implement a communication interfaces between Data Generator, OBU, MEU, and the cloud and these components.

The assumed environment for this project is as follows:

• The Data Generator sends pre-collected real vehicle sensor data to OBU, and OBU forwards the data to MEU.
• MEU verifies the accuracy of the sensor data received from OBU and determines whether there is any anomaly in the vehicle based on the sensor data.
• MEU accumulates the data received from OBU and compresses it to send to the cloud at regular intervals.
• If MEU detects any anomaly in the vehicle, it notifies OBU, which in turn notifies other neighboring OBUs.

To communicate with the Data Generator and MEU, OBU runs a server (Switcher) implemented in Go. Since only C was provided as the interface and development environment for inter-OBU communication, I implemented a communication module (Forwarder) in C. Switcher creates Forwarder as a child process to enable communication with other OBUs through standard input/output streams. The Data Generator is a program that provides a GUI to manipulate the data being transmitted and was developed in C# on .NET. MEU was developed in Java on Android.

In the above environment, if the MEU (which is user's smartphone) does not function properly, I designed a fault-tolerant model using RSU to enable OBU to process sensor data and transmit it to the cloud even in the event of a fault in MEU.

In the above environment, I designed a fault-tolerant model using RSU to enable OBU to process sensor data and transmit it to the cloud even in the event of a fault in the MEU (which is user's smartphone):

• If the connection between OBU and MEU is lost, OBU sends sensor data to RSU.
• RSU communicates with multiple OBUs within its coverage and acts as a proxy for data processing.
• Since vehicles can move to another coverage area, RSUs communicate with adjacent RSUs and transfer data if necessary.

The Switcher in OBU communicates with MEU via WebSocket. I implemented the Switcher to exchange Ping-Pong frames with MEU at a dynamic interval, as defined in the WebSocket spec, to detect the connection status within half of the message transmission delay. If the connection is lost, the Switcher retransmits the data that was just before the disconnection to the RSU. To minimize resource usage in RSU, I applied a personal research-perpose serverless platform called Mee6aaS, which is used only when a fault occurs in MEU.