On the Wyner-Ziv Coding Problem with Delayed Side Information

Lossy Compression Using Side Information Whose Correlation is Shifted

Abstract

Wyner-Ziv coding is a basic and typical source coding for multiple information sources. In Wyner-Ziv coding, the encoder encodes only one of two fixed-length source sequences individually emitted from two correlated sources. Then, the decoder decodes the encoded sequence by referring to the other source sequence as side information, where the decoded sequence is allowed to exhibit distortion from the original sequence. In this Wyner-Ziv coding, it is assumed that the decoder can receive a side information sequence without delay. On the other hand, we previously introduced Wyner-Ziv coding with delayed side information and gave computable upper and lower bounds on the rate-distortion function representing the infimum of the coding rate with respect to a given tolerance level of the distortion. By using these bounds, we showed that there exists a case where the rate-distortion function for a given tolerance level is strictly larger than that for the case without delay. In this paper, we first give known results for lossy source coding without side information or Wyner-Ziv coding. Then, we provide a detailed discussion of our above results. Furthermore, we introduce an information source whose rate-distortion function for a given tolerance level is strictly larger than that for the case without delay and show a numerical example of the rate-distortion function for this source.