Scheduling Algorithms for Wireless Downlink with Deadline and Retransmission Constraints

Packet scheduling for wireless downlink to multiple nodes with deadline and retransmission constraints plays an important role in supporting real-time applications. In this paper, under independent packet arrival processes for different nodes, we formulate this downlink problem as a Markov Decision Process (MDP) by considering all the packets in the queues for all the nodes and obtain a deterministic stationary -optimal scheduling policy. To reduce the exponential complexity due to possibly multiple packets in each queue, we modify this MDP by only considering the head-of-line (HoL) packets, and obtain a heuristic scheduling policy. Simulation results show that the proposed heuristic policy achieves near-optimal performance and outperforms three baselines.