Iterative joint video and channel decoding in a trellis-based vector-quantized video codec and trellis-coded modulation aided wireless videophone
Robert G. Maunder, Jörg Kliewer, Soon Xin Ng, J. Wang, Lie‐Liang Yang, Lajos Hanzo · 2006
Abstract – We propose a Vector-Quantized (VQ) video codec that induces deliberately-introduced code constraints. The complete set of these code constraints are unambiguously described by a novel block-based modification of a symbol-based variable length coding trellis struc-ture. This trellis is employed during VQ encoding to represent video information with a Minimum Mean Squared Error (MMSE) recon-struction. Additionally, the proposed trellis structure is employed in the video decoder to obtain a posteriori probability based MMSE estimates of the transmitted VQ tiles. Since the trellis structure unambiguously describes the code constraints induced by the video codec, its employ-ment guarantees the automatic recovery of valid sets of VQ tiles. The proposed video codec is serially concatenated with a trellis-coded modu-lation scheme for transmission over a fast-fading Rayleigh fading chan-nel. In the receiver, iterative-decoding convergence that eliminates all perceivable channel-induced video distortion is shown to be supported within 1.29 dB of the system’s 2 bit/s/Hz channel-capacity limit of 3.96 dB. I.