Design of a Reliable Communication System for Grid-Style Traffic Control Networks

This paper designs and analyzes the performance of a reliable communication scheme for the traffic control system built upon a wireless process control protocol, aiming at enhancing the robustness and timeliness of the safetycritical control applications. Focusing on the slot-based predictable access and the grid topology of urban area road networks, the proposed scheme establishes one primary and secondary route from the controller to each other node and allocates the time slots accordingly. A split-merge operation makes a sender node sense the primary channel (channel to the primary receiver) and take the secondary channel if the first one is not clear in a single slot, while making the receiver first listen to the primary sender and switches to the secondary sender. In addition, for the sake of finding the path having the lowest error rate, the split-merge operation is modeled as a single virtual link to exploit the shortest path algorithm. We evaluate the performance of our scheme by simulation using a discrete event scheduler. The experimental results show that the proposed scheme enhances the transmission success ratio for the 4 × 4 grid by up to 7.9 %, much more improving the ratio for long-hop nodes. In addition, the routing scheme can find the path that can improve the delivery ratio of control messages by up to 6.69 % for the given performance parameters, compared with the normal grid routing scheme.