Preamble slice orderly queue access scheme in cell-free dense communication systems

Abstract

High reliability applications in dense access scenarios have become one of the main goals of 6G environments. To solve the access collision of dense Machine Type Communication (MTC) devices in cell-free communication systems, an intelligent cooperative secure access scheme based on multi-agent reinforcement learning and federated learning is proposed, that is, the Preamble Slice Orderly Queue Access (PSOQA) scheme. In this scheme, the preamble arrangement is combined with the access control. The preamble arrangement is realized by preamble slices which is from the virtual preamble pool. The access devices learn to queue orderly by deep reinforcement learning. The orderly queue weakens the random and avoids collision. A preamble slice is assigned to an orderly access queue at each access time. The orderly queue is determined by interaction information among multiple agents. With the federated reinforcement learning framework, the PSOQA scheme is implemented to guarantee the privacy and security of agents. Finally, the access performance of PSOQA is compared with other random contention schemes in different load scenarios. Simulation results show that PSOQA can not only improve the access success rate but also guarantee low-latency tolerant performances.