Deep Reinforcement Learning Based Time-Domain Interference Alignment Scheduling for Underwater Acoustic Networks

Message conflicts caused by large propagation delays severely affect the performance of Underwater Acoustic Networks (UWANs). It is necessary to design an efficient transmission scheduling algorithm to improve the network performance. Therefore, we propose a Deep Reinforcement Learning (DRL) based Time-Domain Interference Alignment (TDIA) scheduling algorithm (called DRLSA-IA). The main objective of DRLSA-IA is to increase network throughput and reduce collisions. In DRLSA-IA, underwater nodes are regarded as agents of DRL. Nodes intelligently learn the scheduling by continuously interacting with the environment. Therefore, DRLSA-IA is suitable for the highly dynamic underwater environment. Moreover, we design a TDIA-based reward mechanism to improve the network throughput. With the TDIA-based reward mechanism, DRLSA-IA can achieve parallel transmissions and effectively reduce conflicts. Unlike other TDIA-based algorithms that require enumeration of the state space, nodes merely feed the current state to obtain the transmission decision. DRLSA-IA solves the problem of computational expense. Simulation results show that DRLSA-IA can greatly improve the network performance, especially in terms of throughput, packet delivery ratio and fairness under different network settings. Overall, DRLSA-IA can effectively improve network performance and is suitable for ever-changing underwater environments.