Federated Multiagent Soft Actor Critic for IRS Assisted Cognitive Radio Networks under Partial Observability

Abstract: Intelligent reflecting surfaces (IRSs) can improve spectrum efficiency and interference control in cognitive radio networks (CRNs) by reconfiguring the propagation environment. This paper presents FMASAC, a federated multi-agent soft actor-critic framework for IRS-assisted CRNs under partial observability, in which distributed secondary users (SUs) jointly select their transmit power and the phase shifts of an assigned subset of IRS elements using only local observations. Primary user (PU) protection is incorporated through an interference-penalized reward, and SUs coordinate by periodically averaging model parameters at a federated server, without exchanging raw observations, channel state information, or replay data. We formulate the problem as a partially observable Markov decision process, specify the local learning and aggregation procedure, and characterize its per-round communication cost. Illustrative performance trends contrast FMASAC with centralized SAC, independent SAC, IRS-fixed multi-agent reinforcement learning, and a heuristic CRN strategy. We also outline the simulation-based evaluation and the open challenges, namely constraint handling, agent heterogeneity, and scalability, that are needed to validate the framework.