Zero-error codes for correlated information sources

Slepian and Wolf [2] gave a characterization for the compression region of distributed correlated sources. Their result is for codes with a decoding probability of error approaching zero as the code length is increased. Of interest in many applications is to find codes for which the probability of error is exactly zero. For this latter case block codes using the zero-error information between the sources have been proposed by Witsenhausen [3]. Better codes, however, can be obtained by further exploitation of the statistical dependency impeded in the correlation information. In this paper variable-length zero-error codes are proposed that are generally more efficient than Witsenhausen codes. A method for their construction is presented and an example demonstrating such construction with the achieved rate region are given.