An Integrated Unequal Error Protection Scheme for the Transmission of Compressed Images with ARQ

In this paper we propose a new image transmission scheme for an image which has been compressed using wavelet image compression and coded with a Variable Length Code. The proposed scheme applies Unequal Error Protection (UEP) at three different stages, namely the source coding, channel coding and retransmission stage. UEP at the source coding stage is employed to unequally protect the image subbands against error propagation, which arises due to variable length coding. At the channel coding stage, UEP is applied by the use of Rate Compatible Punctured Convolutional codes to unequally allocate coding redundancy to the image subbands. Finally at the retransmission stage, UEP is applied by assigning different synchronization error tolerances to the image subbands. Gains of over 4 dB in terms of Peak to Peak Signal to Noise Ratio (PSNR) is achieved by employing the integrated UEP scheme as compared to a standard Equal Error Protection Scheme.