On t-Error Correcting/All Unidirectional Error Detecting Codes

We present families of binary systematic codes that can correct t random errors and detect more than t unidirectional errors. As in recent papers, we start by encoding the k information symbols into a codeword of an [n', k, 2t + 11 error correcting code. The second step of our construction involves adding more bits to this linear error correcting code in order to obtain the detection capability of all unidirectional errors. Asymmetric error correcting codes turn out to be a powerful tool in our construction. The resulting codes sensibly improve previous results. Asymptotic estimates and decoding algorithms are presented.