MAP Source-Controlled Channel Decoding with Interleavers for MPEG-4 Image Indoor Wireless Transmission Systems

Srijidtra MAHAPAKULCHAI  Chalie CHAROENLARPNOPPARUT  

Publication
IEICE TRANSACTIONS on Communications   Vol.E92-B   No.10   pp.3052-3059
Publication Date: 2009/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.3052
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Advanced Information and Communication Technologies and Services in Conjunction with Main Topics of APCC/COIN 2008)
Category: 
Keyword: 
MAP decoding,  random and semirandom interleaver,  ring convolutional codes,  Rician block-fading channels,  

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Summary: 
In the modern day, MPEG-4 image compression technique have been commonly applied in various indoor wireless communication systems. The efficient system design mostly relies on the joint source channel coding algorithms, which aim to reduce the complexity of channel coding process, while maintaining the quality of the receiving images. In this paper, we design the MAP source-controlled channel decoders with both random and semirandom interleavers for Rician slow flat block-fading channels. The MAP-Viterbi decoder employs the residual redundancy from zerotree symbol sequences of MPEG-4 HFS packets. The interleaving processes are done after the overall channel coding process to combat the block-fading effects. The computer simulations summarize the system performance in terms of average WER and PSNR (dB). With the interleavers, the significant improvement in PSNR of about 15-17 dB is obtained for both ML and MAP decoding. Also in many cases, we obtain more improvement of about 0.2-0.4 dB for using MAP decoding with the interleavers.