Unidirectional error control codes

A new class of codes for unidirectional error control is presented. These codes are targeted towards unidirectional errors which affect at most t bits confined at most u bytes of a code word. Such errors are termed t/u-unidirectional errors. t/u-unidirectional error control, in general, requires lesser redundancy as compared to u unidirectional byte error control codes. Codes that are capable of detecting, locating and correcting t/1-unidirectional errors are presented. It is shown that unidirectional error location can be achieved with lesser redundancy as compared to unidirectional error correction. This result is interesting because symmetric error location with linear codes has been previously shown to require as much redundancy as symmetric error correction.