2-channel oversampled filter banks as joint source-channel codes for erasure channels
This paper studies oversampled filter banks (OFB) for robust transmission of image/video signals over erasure channels. The dependencies introduced by the OFB-based frame expansion are first analyzed in the z domain. This analysis paves the way to the design of an algorithm for message reconstruction in presence of erasures and quantization noise. Conditions for recovery from some typical erasure patterns like bursty erasures and periodic erasure patterns are derived for both orthogonal and biorthogonal filter banks. For some erasure patterns the equivalent transform coder forms a frame, hence the reconstruction could be based on operating its pseudo inverse, however at the expense of high computational cost. Alternately, the erased samples can first be reconstructed from the received ones and then signal space projection can be applied. Since in practical systems the codevectors are quantized before transmission, we study the effect of quantization noise on the reconstructed signal. The theoretical results are validated for a number of erasure patterns with image signals.