A Fairness-Aware Scheduling Algorithm for Industrial Wireless Sensor Networks with Multiple Access Points

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.