Digital video in a fading interference wireless environment

Much research and development related to digital video has targeted storage, wired backbone, and broadcast wireless transport environments. Here we address video transport in a heterogeneous network, especially with interference-and fading-dominated wireless access, such as a cellular local-area or wide-area network. It is expected that multimedia (including video) will be an important application for desktop computers, and this suggests offering similar wireless capabilities. We note a number of deficiencies in existing video compression standards such as MPEG for this environment, and identify a number of challenging new research issues. 1 INTRODUCTION Experience has shown that users welcome tetherless (no wires), nomadic (freedom in the point of network access), and mobile (access while moving) access to networking computing and communications services. Multimedia, and video in particular, should be no exception. Thus, our working hypothesis is that digital video via broadband backbone networks with wireless access deserves serious attention. A transport network is rarely exclusively wireless, but usually incorporates wireless access to a broadband backbone network. Wireless access links present a severe bottleneck in provisioning video and multimedia services, and will only become more so as backbone networks continue to increase in speed. Thus, wireless access will become the primary bottleneck , and the entire system, including the backbone network and the video coding should be designed for maximum efficiency on wireless access links, where they exist. We can identify a number of interrelated objectives: • high subjective quality and low perceptual delay (the latter primarily for the subset of interactive applications); • high traffic capacity; • multicast and unicast topology; • mobility, including transparent inter-cell handoff; • privacy by end-to-end encryption; • scalability to heterogeneous terminals (from desktop to hand-held) and transport links (primarily broadband backbone and wireless access).