A Novel Error Control Algorithm for Reducing Transmission Delay in Real-Time Mobile Video Communication

Naoto MATOBA  Yasushi KONDO  Hiroyuki OHTSUKA  Toshiaki TANAKA  

IEICE TRANSACTIONS on Communications   Vol.E82-B    No.12    pp.2021-2030
Publication Date: 1999/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Multimedia Mobile Communication Systems)
video transmission,  mobile communication,  ARQ,  PHS(Personal Handy-Phone System),  fading channel,  

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This paper proposes a short delay, error-resilient video transmission scheme for mobile radio channels. Compressed video data are sensitive to channel error. Video coding schemes such as H. 263 use variable length coding so channel error can cause synchronization failure in the decoder and fatally degrade the reconstructed video sequence by triggering intra- and inter-frame error propagation. ARQ prevents all forms of error propagation but significantly increases the transmission delay of the video frame. We propose a new error control scheme to reduces the delay incurred by ARQ; the receiving buffer can transmits the video frame data to the video decoder even if not all ARQ frames containing the video frame are received. The encoder transmits additional information, the Macro Block (MB) size, in the video frame header. Upon receiving this information, the receiving buffer can determine MB length which allows MB de-synchronization to be prevented. For example, if an ARQ frame is lost, the decoder determines the position of the missing MB and replace this MB with the equivalent block in the previous video frame; this prevents intra-frame error propagation. When all ARQ frames are received and decoded correctly, the video frame in the reference video memory is replaced with the correctly decoded one. Simulation results show that the proposed scheme can minimize the delay and the reduction in frame rate caused by retransmission control without intra- and inter-error propagation.