Work-in-Progress: Utilization Based Schedulability Analysis for Wireless Sensor-Actuator Networks
Dali Ismail, Mahbubur Rahman, Venkata P. Modekurthy, Abusayeed M. Saifullah · 2017
WirelessHART networks provide the feasibility of achieving real-time performance over wireless through multichannel and graph routing for process monitoring and control applications. However, real-time scheduling theory for Wireless Sensor-Actuator Network (WSAN) is still not well-developed. Besides, the performance of a WSAN induces a complicated problem involving many interrelated objectives and variables, requiring a scheduling-control codesign. This work aims at addressing these challenges. Specifically, we will develop a realtime schedulability analysis for WSAN, and leverage this result to address multiple key challenging problems in wireless Cyber-Physical Systems in the future. Schedulability analysis remains the cornerstone in any real-time system. In WSAN, it is used to determine whether a set of real-time control loops/flows can meet deadlines. It is also used in various scheduling-control codesign, routing, and priority assignment. In this work, we will develop an analysis based on utilization bound. Because of its extremely low runtime overhead, utilization based analysis has been extensively studied in CPU scheduling. However, no work has been done yet on utilization based analysis for multi-hop wireless network. The key challenge arises from transmission conflict and dynamics in wireless. We will address this by characterizing transmission conflict as task blocking in nonpreemptive CPU scheduling, and then by adopting a hierarchical network structure where we will apply the analysis in each subnetwork.