Deadline-constrained transmission scheduling and data evacuation in WirelessHART networks

Real-time data delivery is a critical issue in WirelessHART networks. This paper develops a novel mathematical programming framework for joint routing and link scheduling of deadline-constrained traffic in WirelessHART networks. The general framework explores dynamic network flows in a time-expanded graph model and can provide flexible solutions for a variety of real-time data delivery problems. Data evacuation, an important communication paradigm in WirelessHART networks, is a special case of this general framework. We establish the lower bound on evacuation time for line, multi-line and binary tree networks. Moreover, we design a novel scheduling algorithm for data evacuation in binary tree networks, and prove that this scheduling algorithm always achieves the lower bound on evacuation time. We evaluate our scheduling algorithm through numerical simulations, and the results verify that our algorithm minimizes the evacuation time with the least number of channels.