Learning-Based Deterministic Delay Performance Guarantee Strategy in RIS-Assisted Communication Networks

In order to satisfy the requirements for service transformation and upgrading towards industrial digitization, networking, and intelligence, 6G-enabled Industrial Internet of Things (IIoT) imposes new requirements on deterministic delay. However, the existing best-effort communication networks increase the uncertainty of transmission, making it difficult for users to ensure deterministic delay performance. In this paper, we propose a Deterministic Delay Guarantee Strategy (DDGS) under RIS-assisted communication networks to ensure network performance in IIoT scenarios. In particular, we utilize Stochastic Network Calculus (SNC) to derive the probability that the delay falls within a specific time window, characterizing the probabilistic bounds of deterministic delay. Then we explore the relationship between delay determinacy and wireless resources by jointly optimizing the transmit power, the channel blocklength allocation, and the phase-shift matrix at the RIS to maximize delay determinacy. Based on the interdependence of action choices among users and past experience, this paper proposes a Performance Guarantee Parameterized Deep Q-Network (PG-PDQN) algorithm to solve the complex problem containing a mixture of discrete and continuous action spaces. Simulation results show that the DDGS strategy significantly improves the delay determinacy compared to other strategies, and the PG-PDQN algorithm has good convergence, thus effectively improving the network performance.