A Control Loop Reduction Scheme for Wireless Process Control on Traffic Light Networks

This paper designs a loop reduction scheme and measures its performance for the wireless process control application running on the grid-style traffic light network, aiming at improving the response time of the control system. Based on the WirelessHART standard, which assigns a slot to each (sender, receiver) pair according to the routing schedule, the allocation scheme puts all the pairs having no interference to a single slot, reducing the loop length. For further reduction, the classic Dijkstra’s shortest path algorithm is modified such that the number of end-to-end paths starting from the horizontal links and the vertical link, respectively, is almost same. The transmission of the controller, which initiates all message delivery and is the main bottleneck point, will not be blocked. The simulation result demonstrates that the proposed scheme can significantly reduce the control loop length, and the modified path finding algorithm further achieves about 9.8 % improvement, just sacrificing the 3.2 % of transmission success ratio.