Accelerating Reinforcement Learning via Predictive Policy Transfer in 6G RAN Slicing

Reinforcement Learning (RL) algorithms have recently been proposed to solve dynamic radio resource management (RRM) problems in beyond 5G networks. However, RL-based solutions are still not widely adopted in commercial cellular networks. One of the primary reasons for this is the slow convergence of RL agents when they are deployed in a live network and when the network’s context changes significantly. Concurrently, the open radio access network (O-RAN) paradigm promises to give mobile network operators (MNOs) more control over their networks, furthering the need for intelligent and RL-based network management. O-RAN’s standardized interfaces will allow MNOs to make real-time custom changes to intelligently control various RRM functionalities. We consider a RAN slicing scenario in which MNOs can modify the weights of the RL reward function. This enables MNOs to change the priorities of fulfilling the service level agreements of the slices. However, this results in a practical challenge since the RL agent needs to adapt promptly to the changes made by the MNO. This challenge is addressed in this paper, where we first present and discuss the results from an exhaustive experiment to examine the efficiency of using transfer learning (TL) to accelerate the convergence of RL-based RAN slicing in the considered scenario. We then propose a novelpredictiveapproach to enhance the TL-based acceleration by selecting the best-saved policy for reuse. By adopting the proposed policy transfer approach, RL agents are able to converge up to 14000 learning steps faster than their non-accelerated counterparts. The proposed machine learning (ML)-basedpredictiveapproach also shows up to a 96.5% accuracy in selecting the best expert policy to reuse for acceleration.