Adaptive unequal error protection and VLC reshuffling for image transmission over wireless channels
Tin Tak Cheung, Minji So, R.S. Cheng, Khaled B. Letaief · 2002
In the third generation mobile communication systems, multimedia data can be transmitted over wireless channels. Hence, there has been significant amount of research on multimedia (image or video) transmission over wireless links in recent years. However, image and video bit-streams are very sensitive to errors due to the variable length code (VLC) in the compression process. Hence, it is necessary to employ error resilient techniques to protect the data. In this paper, adaptive unequal error protection (AUEP) and VLC reshuffling techniques are proposed. The basic idea of AUEP is to remove a certain number of high frequency DCT coefficients in each long MB according to the current channel characteristics, and allow a stronger channel coding to be applied without additional bandwidth expansion. On the other hand, the VLC reshuffling is used for reordering the important VLCs to the beginning of each MB. The simulation results prove that the proposed scheme gives significant improvement in the image quality.