Exploiting the Temporal Structure of MPEG Video for the Reduction of Bandwidth Requirements

Abstract

We propose a new bandwidth allocation scheme for VBR video traffic in ATM networks. The scheme is tailored to MPEG-coded video sources that require stringent and deterministic quality-of-service guarantees. By exploiting the temporal structure of MPEG sources, we show that our scheme results in an effective bandwidth which, in most cases, is less than the source peak rate. The reduction in the bandwidth requirement is achieved without sacrificing any perceived QoS. Efficient procedures are provided for the computation of the effective bandwidth under heterogeneous MPEG sources. The effective bandwidth strongly depends on the arrangement of the multiplexed streams which is a measure of the degree of synchronization between the GOP patterns of different streams. Assuming that all possible arrangements are equi-probable, we derive an expression for the asymptotic tail distribution of the effective bandwidth. From the tail distribution, we compute several performance measures for the call blocking probability when the allocation is made based on the effective bandwidth. In the case of homogeneous sources, we give a closed-form expression for the best' arrangement that results in the optimal' effective bandwidth. Numerical examples based on real MPEG traces are used to demonstrate the advantages of our scheme. (Also cross-referenced as UMIACS-TR-96-29)