Error detection capability for variable length codes

In many practical systems using variable length codes, a bit stream format is adopted in which synchronous codes are inserted at a certain interval. With such a format, random access to the bit stream becomes possible. If there is an error, resynchronization is possible. In this paper, a method is proposed to quantitatively express the relationship of error detection due to decoding of nonexisting code words in the presence of errors with self‐synchronization by coincidence of the suffix of the code words in the variable length codes used in the above systems. As a model for the channel, the Gilbert model, a classical burst error model, and the binary symmetric channel are used for analysis. It is found that error detection and the self‐synchronization are in a trade‐off relationship and that the reversible variable length codes that are instantaneously decodable in both directions have a high level of error detection capability in the sense that the codes are not self‐synchronized. These results can be used for error resilient technique in coding systems using variable length codes. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 70–79, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10014