Error resilient in MPEG-2 video transmission over wireless ATM networks

Abstract

Audio-visual and other multimedia services are seen as an important source of traffic for current telecommunications networks, including ATM networks. There has been an emerging interest in using ATM for wireless transmission. Because ATM is primarily designed for an essentially error-free environment, in the wireless context the sources of errors and their consequences must be thoroughly understood. While this concern is valid in any network, it takes on a new, more central role in the wireless environment, where error bursts are expected to be a very significant source of degradation. In the transmission process of a VBR video signal over a wireless ATM network, cells are inevitably exposed to errors and losses due to the various physical impairments that occur on the wireless channel. These phenomena affect the quality of the signal and without adequate measures to control the propagation of the impairments the quality of service may fall below acceptable levels. In this paper, we show results on the effect of transmission errors, which can cause cell loss with probabilities as high as 1%, on the quality of the decoded video at the receiver, and demonstrate how error resilience techniques can be used to improve the quality of service. Most important among the findings is that the error resilient techniques provided within the MPEG-2 standard are not sufficient to provide acceptable quality, but that this quality can be significantly increased by the inclusion of a small number of simple additional techniques.