QoS management for video delivery over mobile wireless networks.

摘要

It is anticipated that wireless multimedia services will find widespread acceptance over the next decade. The objectives that shaped current second-generation wireless networks have been expanded in third-generation wireless information networks to provide truly ubiquitous access and integrated multimedia services [88].; However, to make the vision of ubiquitous wireless multimedia communications a reality, many technical problems remain to be solved. The combination of bit-rate variability of compressed video traffic and inferior quality of a wireless fading channel causes low bandwidth efficiency, high data-error rate, and long delay to wireless multimedia applications.; This research tries to provide solutions to those problems. Guided by the end-to-end quality-of-service (QoS) management fundamental principles, following two issues are studied: (1) bit-rate variability and bandwidth requirement reductions at an application layer and (2) QoS concerned error control at a data-link layer.; The former alleviates resource consumption pressure from the lower network layer; the later conceals adverse properties of a wireless channel from the upper network layer. As the result, the QoS constrained wireless multimedia applications are possible.; In the first part of the dissertation, we address the problem of how to represent a video stream in a way that can reduce network resource requirement without sacrificing the video stream's quality. An original buffer-less scene-based traffic-shaping algorithm and a QoS concerned traffic-shaping algorithm are contributed. The performances and potential applications of these algorithms are evaluated.; In the second part of the dissertation, we address the problem of how to transmit a video stream at a data-link layer with QoS constrains. A novel QoS aware error control scheme (QSR-ARQ) and its improved version, hybrid QSR-ARQ (HQSR-ARQ), are proposed. The design philosophy, the computer simulation configuration, the performance analysis, and the compute simulation results are presented.