We propose a class of rate-distortion optimized packet scheduling algorithms for streaming media by generating a number of nested substreams, with more important streams embedding less important ones in a progressive manner. Our goal is to determine the optimum substream to send at any moment in time, using feedback information from the receiver and statistical characteristics of the video. To do so, we model the streaming system as a queueing system, compute the run-time decoding failure probability of a group of picture in each substream based on effective bandwidth approach, and determine the optimum substream to be sent at that moment in time. We evaluate our scheduling scheme with various video traffic models featuring short-range dependency (SRD), long-range dependency (LRD), and/or multifractal properties. From experiments with real video data, we show that our proposed scheduling scheme outperforms the conventional sequential sending scheme.

We propose a class of packet scheduling algorithms for streaming media. The importance level of a video packet is determined by its relative position within its group of pictures, taking into account the motion-texture discrimination and temporal scalability. We generate a number of nested substreams, with more important streams embedding less important ones in a progressive manner. We model the streaming system as a queueing system, compute the run-time decoding failure probability of a frame in each substream based on effective bandwidth, and determine the optimum substream to be sent at any moment in time. The data within optimum substream is sent based on earliest-deadline-first scheduling, until the next channel report arrives, at which time the optimum substream is recomputed. From experiments with real video data, we show that our proposed scheduling scheme outperforms the conventional sequential sending scheme.

We consider a common-memory (CM) type N/spl times/N ATM switch, where the CM block consists of K (K/spl ges/N) sub-memories (SM). We propose an address assigning algorithm to avoid input/output contentions so that we can have the read/write speed of each SM as low as the interface port speed. Taking the replication-at-sending approach, we pursue memory and bandwidth efficiency for a multicast cell output. We evaluate the system in terms of cell loss ratio and average delay time. We take into account two loss factors: (1) the failure of scheduling to avoid input/output contentions; (2) overflow in the CM block.