Transmission scheduling for mixed-critical multi-user multiple-input and multiple-output industrial cyber-physical systems

Abstract

Wireless sensor networks are widely used in industrial cyber-physical system installations, where high reliability and the need for real-time data are the two main characteristics. A large amount of real-time data can be transmitted to its destination on time using a reasonable periodic allocation of a node's transmission slots. However, a flow may miss its deadline when flow conflicts occur. When such missed deadlines occur regularly, system performance may degrade, and when the flow is critical, such data losses can result in errors or cause disasters. To address this issue, we introduce multiuser multiple-input and multiple-output technology and a mixed-critical system into an industrial cyber-physical system. When an error occurs or when demand changes, the multiuser multiple-input and multiple-output nodes can switch their transmission mode, changing to a high-criticality configuration to meet the system's new needs. Hence, we first propose a heterogeneous multiuser multiple-input and multiple-output system model. Based on this model, we propose a slot analyzing algorithm that guarantees system schedulability by reallocating slots for each node after replacing conflict nodes with multiuser multiple-input and multiple-output nodes. By considering both system schedulability and cost, the slot analyzing algorithm also reduces the number of multiuser multiple-input and multiple-output nodes required. Then, to further reduce the number of multiuser multiple-input and multiple-output nodes in an industrial cyber-physical system, we propose a priority inversion algorithm that improves schedulability by adjusting slot allocations before replacing conflict nodes with multiuser multiple-input and multiple-output nodes. By reducing the use of multiuser multiple-input and multiple-output nodes, the priority inversion algorithm achieves better performance than the slot analyzing algorithm when the system is in a high-criticality mode. Evaluation results show the effectiveness and efficacy of our approaches.

Multiprocessor Scheduling meets the Industrial Wireless

“…In the WirelessHART-like networks, besides the results already discussed, other works have been presented in Saifullah et al (2011b), Wu et al (2016) and Modekurthy, Saifullah, and Madria (2018). In other domains, the results presented here were applied to other wireless contexts such as heterogeneous industrial networks (Xia et al 2017b), multi-use multiple-input multiple-output industrial network (Xia et al 2017c), scheduling of emergency tasks in industrial networks (Xia et al 2017d) and hierarchical data transmission in industrial WSANs (Jin et al 2017). Indeed, in its broadest sense, all of the articles covered in this review may have interesting implications in wireless networked control systems (WNCS) and wireless cyber-physical systems (WCPS), where there are other relevant applications such as intra-vehicle wireless networks, wireless avionics intra-communications, and building automation.…”

The AirTight Protocol for Mixed Criticality Wireless CPS

“…The evaluation considers schedulability parameters but does not consider the impact of temporal faults upon the system. Recently, multiple-input multiple-output (MIMO) antenna technology has also been applied in mixed-criticality CPS [39] in order to provide additional capacity for HI-criticality ows at bottlenecks. Although shown to improve schedulability performance, the requirements for some heterogeneous hardware (MIMO) nodes would be an additional installation cost.…”

“…Xia et al [41] does not incorporate mode changes so cannot free up additional processing to handle the fault situation by stopping LO transmissions; [40] considers schedulability parameters but does not consider the impact of long-lasting temporal faults. Compared to [39] which requires MIMO antennas and [12] which relies upon SDRs, AirTight is capable of functioning upon existing commodity devices with xed radio transceivers.…”