On Optimal Scheduling Methods For Industrial WirelessHART Networks

As the advanced development of wireless communication technology,industrial wireless networks have been widely used in many industrial applications,due to their low cost,well flexibility and scalability.However,the tough environment and stringent requirements of industrial applications on real-timeliness and reliability bring many challenges to industrial wireless networks.Wireless HART is one of the most widely used wireless standards in industrial applications,which applies many special designs to meet the critical industrial requirements,such as channel blacklisting,time slotted channel hopping(TSCH),graph routing and so on.These mechanisms can improve the real-time and reliable performance of Wireless HART networks,however,they also significantly increase the complexity of network scheduling.Motivated by this,this paper systematically studies the channel selection,time scheduling and channel allocation problems in industrial Wireless HART networks,and proposes optimal scheduling policies for these problems.The contributions of this paper can be summarized as follows:1.We study the problem of channel list selection in Wireless HART networks.To achieve more accurate channel assessment,we first propose a LSTM-based model to predict the packet reception ratio(PRR)of the next superframe.Based on which,we design a channel selection algorithm to balance the route diversity and channel diversity.2.This paper studies the problem of joint scheduling and channel allocation for end-to-end delay optimization in Wireless HART networks.We propose a tuple-based multi-dimensional conflict graph,based on which the latency optimization problem is formulated as an integer program.We then develop an iterative hop-wise scheduling algorithm to solve the problem,which decomposes and transforms the original problem into a series of maximum weighted independent set problems.In addition,the schedulability of the problem and the suboptimality of the proposed algorithm is analyzed.3.We study three kinds of complex transmission scenarios in Wireless HART networks,i.e.graph routing,heterogeneous flow length,and flows with deadline constraints,and extend the multi-dimensional conflict graph model and the proposed algorithm to accommodate these scenarios effectively.Finally,our work is concluded and we carry out a discussion on the future work.