DRL based Flexible LDM Scheme for Mixed Unicast-Broadcast Transmission in 5G.

With the increasing demand for data, radio resources are increasingly scarce. The cooperative transmission mechanism, which allows broadcast and unicast to share the same spectrum, can effectively alleviate this situation. The success of LDM in ATSC 3.0 has inspired many scholars to superimpose broadcast and unicast services with a fixed power injection ratio. To further improve radio resource utilization, we propose a flexible LDM scheme with variable power injection ratios in this paper. Then we formulate the scheduling policy in the MAC layer as a sequential decision problem and prove it has Markov property. We propose a DRL-based algorithm to obtain the optimal scheduling scheme. Simulation results show that the proposed scheme can achieve superior performance in system throughput.