Energy-Efficient Scalable Video Multicasting for Overlapping Groups in a Mobile WiMAX Network

Abstract

Scalable video coding, together with adaptive modulation and coding, is a promising technique for providing real-time video multicast services on mobile stations (MSs) in heterogeneous channel conditions. On the other hand, since MSs are often powered by batteries, reducing the energy consumption of mobile devices is an important concern. In this paper, we study the problem of scalable video multicast scheduling in a mobile worldwide interoperability for microwave access (WiMAX) network with the objective of maximizing the multicast energy throughput. This problem has never been seriously studied when the assumption that different multicast groups may partially overlap is made. We prove that this problem is NP-complete. Our proposed solution, which is called energy-efficient multicast scheduling with adaptive modulation and coding (EEMS-AMC), consists of three modules, namely, online admission control, base-layer data scheduling, and enhancement-layer data scheduling. The admission control rules not only help the base station to admit the maximum number of video streams but ensure that the video data can be delivered to mobile users within the timeliness requirement as well. Moreover, EEMS-AMC adopts the greedy strategy to schedule base-layer data such that even in the worst-case scenario, the average duty cycle of admitted MSs can be within a bounded factor from the theoretical minimum. Finally, EEMS-AMC employs the metric “expected multicast throughput” to derive the proper modulation and coding scheme for each enhancement-layer data and employs the metric “marginal multicast energy throughput” to efficiently derive near-optimal enhancement-layer data scheduling. Simulation results exhibit that EEMS-AMC achieves relatively good performances in terms of multicast energy throughput and normalized total utility.