Turbo cross decoding of multiple descriptions

The transmission of multimedia data over best-effort packet networks has motivated a strong research effort in the area of multiple description coding. While most contributions concentrate on the design of encoders for the erasure channel, this paper considers the transmission of multiple descriptions over a typical wireless link. Assuming that channel state information is available and that the reliability of each transmitted bit is known to the receiver, we present a soft-in/soft-out decoder for a new class of block codes derived from multiple description scalar quantization. The idea of cross decoding multiple descriptions using soft information, can be successfully extended to the concatenation of multiple description codes and convolutional codes. For this case, the application of the turbo principle yields an iterative decoding scheme, which makes use of the correlation between descriptions in a very effective way.