Systematic Unidirectional Error-Detecting Codes

Abstract

The theory and design of systematic t-unidirectional error-detecting codes are developed. Optimal systematic codes capable of detecting 2, 3, and 6 unidirectional errors using 2, 3, and 4 check bits, respectively, are given. For r ≥5 where r is the number of check bits, the systematic codes described here can detect up to 5· 2r-4 + r -4 unidirectional errors. Encoding/ decoding methods for these codes are also investigated.