Iterative decoding of differentially space-time coded multiple descriptions of images

We consider transporting images over wireless fading channels rather than the on-off channels considered in most works related to multiple description (MD) coding. The new idea is to use iterative (turbo) decoding techniques developed for serially concatenated coding systems to improve the performance of the receiver in successive decoding iterations. We treat MD coding, realized by embedded image coding plus unequal error protection (e.g., product code structure), as the outer constituent code and use a differential space-time code as the inner constituent code. Experimental results show that our iterative scheme can effectively improve the system performance. Furthermore, most of the gain in PSNR is achieved with only one iteration in the low SNR range, e.g., 0-20 dB.