Downlink Wireless Packet Scheduling with Deadlines TO APPEAR IN THE IEEE TRANSACTIONS ON MOBILE COMPUTING

Next generation cellular wireless communication networks aim to provide a variety of quality-ofservice (QoS) sensitive packet based services to downlink users. Included amongst these are real-time multimedia services, which have stringent delay requirements. Downlink packet scheduling at the base station plays a key role in efficiently allocating system resources to meet the desired level of QoS for various users. In this paper, we employ dynamic programming (DP) to study the design of a downlink packet scheduler capable of supporting real-time multimedia applications. Under well justified modeling reductions, we extensively characterize structural properties of the optimal control associated with the DP problem. We leverage intuition gained from these properties to propose a heuristic scheduling policy, namely CA-EDD (Channel Aware Earliest Due Date), which is based on a “quasi-static” approach to scheduling. The per time-slot implementation complexity of CA-EDD is only O(K) for a system with K downlink users. Our simulation results demonstrate that CA-EDD comfortably outperforms benchmark schedulers, both in terms of overall system performance and fairness. CA-EDD achieves these performance gains by using channel and deadline information in conjunction with application layer information (relative importance of packets) in a systematic and unified way for scheduling.