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Abstract-Real-timeliness and reliability are two basic requirements for industrial wireless sensor networks (IWSNs). In this paper, periodic heterogeneous traffics with delay constraints are concerned in an IWSN with multiple access points (thus forming a redundant star topology). In order to improve the reliability while meeting the real-timeliness and fairness, we propose a fairness-aware scheduling (FAS) algorithm, in which three heuristic rules are first designed based on a novel penalty mechanism. Then, in each slot field devices are classified into six priorities according to the above three rules. Finally, the current slot is allocated to field devices in accordance with their priorities and communication ranges in a space division multiplexing way. A performance study is carried out by simulation, and the results show that the proposed FAS algorithm performs much better than existing works in terms of reliability and fairness.

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In industrial wireless sensor networks (IWSNs), monitoring data generated by field devices (FDs) are supposed to be delivered to the gateway timely and reliably. The previous researches focus on the convergecast problem based on the global available channel set, where unreliable channels are blacklisted. However, in practical industrial environment, different links may have different local available channel sets (LACSs) due to the location-dependent characteristics of wireless channels. In this paper, we study the LACSs-based convergecast scheduling problem in the IWSNs with tree topologies. First, we formulate the convergecast scheduling problem in a mathematically precise form of integer programming. Then, we propose a novel method to calculate priorities for each FD, and design two effective heuristic rules of allocating channels to FDs to maximize the number of concurrent transmissions in each time slot, considering the priority of each FD and the constraints in the integer programming formulation. Finally, inspired by the proposed heuristic rules, we propose an LACSs-based convergecast scheduling (LCS) algorithms to generate efficient schedules for IWSNs in polynomial time. The simulation results show that the proposed algorithm outperforms existing works in terms of latency for different scenarios. Index Terms-Industrial wireless sensor networks, convergecast scheduling, available channel sets, real-time, channel blacklisting. I. INTRODUCTION A S one of the most critical technologies for intelligent manufacturing, industrial wireless sensor networks (IWSNs) are being widely adopted in smart factories [1]-[3].