ABSTRACT
482This chapter presents the optimization techniques on packet scheduling algorithms for supporting multimedia content delivery in mobile Digital Multimedia Broadcasting (DMB). Such services include, for example, e-mail, Web browsing, streaming video/audio, and so on. On one hand, a great deal of research effort has been put on the optimization of packet scheduling schemes for both wired and wireless systems, aimed at maximizing the resource utilization and spectrum efficiency. On the other hand, there has also been work relating to the optimized packet scheduling performance via cross-layer design, obtaining performance gains by actively exploiting the dependence between protocol layers. In this chapter, we take a step in that direction by presenting a literature survey of the packet scheduling optimization techniques in both wired and wireless systems, and by addressing the quality-of-service (QoS) guarantees and performance trade-offs among these schemes. In particular, we consider the development and evaluation of a cross-layer packet scheduling scheme in a uni directional geostationary (GEO) satellite broadcast system, namely, the Satellite Digital Multimedia Broadcasting (SDMB) system, which plays a key role in the convergence of a closer interworking between terrestrial and satellite communications for a more efficient multimedia provisioning. The chapter is organized as follows. In section 18.1, a survey of packet scheduling algorithms in general wired networks is first discussed, with examples drawn from the literature. The adaptation and optimization techniques of packet scheduling algorithms in wireless systems are analyzed in section 18.2. In section 18.3, packet scheduling in SDMB is discussed and existing packet scheduling schemes in such a system are reviewed. In section 18.4, a cross-layer-based packet scheduling scheme, which comprises combined delay and rate differentiation (CDRD) service prioritization and dynamic resource allocation (DRA) algorithms, is presented for QoS provisioning in the SDMB system, followed by the performance evaluation and discussion on the optimized packet scheduling scheme. Finally, we summarize the chapter by raising some opportunities and challenges related to this research, and researchers developing packet scheduling schemes in digital multimedia broadcasting may want to address these as they move forward.
