On the capabilities of error concealment in MPEG-2 communications over wireless ATM

摘要

Because ATM is primarily designed for an essentially error-free environment, in a 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 video quality may fall below acceptable levels. We show results on the effect of cell loss due to transmission errors on the quality of the decoded video at the receiver, and demonstrate how packing strategies and error concealment mechanisms can be used to improve the quality of video. We assess the adequacy of using a dynamic concealment algorithm and deduce the most appropriate values of the parameters of this algorithm.