Scheduling Strategy Design Framework for Cyber-Physical System with Non-Negligible Propagation Delay

Area of Science:

• Cyber-Physical Systems (CPS)
• Wireless Networked Control Systems (WNCS)
• Control Theory

Background:

• Cyber-physical systems (CPS) are widely used as wireless control networks, often based on wireless networked control systems (WNCS).
• These systems feature closed-loop control with uplink and downlink transmissions, crucial for time-sensitive applications.
• Existing research often overlooks the significant impact of uplink and downlink propagation delays in CPS/WNCS.

Purpose of the Study:

• To develop a heuristic framework for optimizing scheduling strategies in CPS/WNCS.
• To minimize the long-term average control cost by addressing uplink and downlink propagation delays.
• To achieve a better balance between uplink and downlink transmissions.

Main Methods:

• Modeling the optimization problem as a Markov decision process (MDP).
• Proposing a semi-predictive framework to mitigate coupling effects between uplink and downlink data packets.
• Developing both a lookup table-based optimal offline strategy and a neural network-based suboptimal online strategy.

Main Results:

• Sufficient conditions for the existence of an optimal scheduling strategy were established.
• The proposed framework effectively eliminates the impact of coupling characteristics between uplink and downlink data packets.
• Numerical simulations demonstrated significant performance improvements compared to existing strategies.

Conclusions:

• The developed heuristic framework provides effective scheduling strategies for CPS/WNCS with non-negligible propagation delays.
• The semi-predictive approach and derived strategies offer substantial performance gains in time-sensitive applications.
• This work addresses a critical gap in existing CPS/WNCS research by incorporating propagation delay.