PERFORMANCE ANALYSIS OF CELL DISCARDING TECHNIQUES FOR BEST EFFORT VIDEO COMMUNICATIONS OVER ATM NETWORKS

With increasing interest in the transmission of audio-visual applicati ons over ATM best effort services, efficient video-oriented control me chanisms for improving the video quality in the presence of loss have to be designed. In this paper, we propose and evaluate two new slice-b ased discard schemes for use with available bit rate and guaranteed fr ame rate services (ef formerly UBR +). The schemes adaptively and sele ctively adjust the discard level to switch buffer occupancy and video cell payload types. To improve their performance, we also introduce a dynamic frame-level priority data partition technique based on MPEG da ta structure and feedback from the network. To support these mechanism s, enhancements to the ATM adaptation layer 5 and a new MPEG-2 encapsu lation strategy are also proposed. The presented quality of picture (Q oP) control framework is evaluated using simulation and actual MPEG vi deo data. The overall aim of the framework is double. First, ensuring a graceful picture quality degradation by minimizing cell loss probabi lity for critical video data, and second optimizing the network effect ive throughput by reducing transmission of non useful data. In compari son to previous approaches, the performance evaluation have shown a si gnificant reduction of the bad throughput and minimization of losses o f intra-and predictive-coded flames at both cell and slice layers. (C) 1998 Elsevier Science B.V.