Abstract

Weinvestigate the interaction of congestion control with the partitioning of source information into components of varying importance for variable bit rate packet voice and packet video. High priority transport for the more important signal components results in substantially increased objective service quality. Using a Markovchain voice source model with simple PCM speech encoding and a priority queue, simulation results show a signal-to-noise ratio improvementof45dBwithtwo priorities over an unprioritized system. Performance is sensitive to the fraction of traffic placed in eachpriority, and the optimal partition depends on network loss conditions. When this partition is optimized dynamically, quality degrades gracefully over a wide range of load values. Results with DCT encoded speech and video samples show similar behavior. Variations are investigated such as further partition of low priority information into multiple priorities. A simulation with delay added to represe...

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