Error concealment based on MMSE estimation for multimedia wireless and IP applications

This paper presents a framework for the error concealment of multimedia signals transmitted over wireless and IP networks. This framework is based on two elements. First, the replacements for the erroneous channel outputs are obtained from a minimum mean square error (MMSE) estimation which takes into account both the source and all the available information from the transmission channel. Then, hidden Markov models (HMMs) provide the required stochastic modeling which allows the estimation. This modeling makes it possible a natural integration of the two types of information (source and available data from the channel). This framework is developed for both, wireless channels with errors at the bit level and packet channels degraded by packet loss. In the first case, a very high performance can be obtained even without the need of soft decision or any type of channel SNR estimation. In the second case, the lack of channel outputs during packet losses must be compensated either by enhancing the source model (increasing the model order) or by introducing media-specific FEC codes which may substitute the missing packets. This second option has yielded higher performance than the first one.