Concealment of Erroneous or Lost Frames

Abstract

Digital speech, audio, and video communication over noisy channels usually comprises source and channel coding. Channel encoders are designed and optimized for a typically expected minimum quality of the transmission channel. However, in practice, more adverse channel conditions occur, and the error correction scheme is overloaded such that residual bit errors remain after channel decoding. This may result in severe degradations of the signal and subjectively annoying effects, which can be reduced or even eliminated by means of error concealment. This chapter discusses basic ideas for error concealment. Then, a generic approach will be presented, which is called soft decision source decoding. It can be applied to any parametric source decoder as it relies on residual source redundancy, reliability information from the channel, and optimum parameter estimation or joint source-channel decoding. Finally, a few standardized error concealment examples will be described that are applied in the mobile radio systems GSM, UMTS, and LTE.

Authors 2

1. Peter Vary Aachen Institute of Communication Systems

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Institute of Communication Systems, Aachen, Germany

2. Rainer Martin

   Ruhr University Bochum

   Affiliation as printed

   Ruhr-Universität Bochum, Institute of Communication Acoustics, Bochum, Germany