A CONSTRUCTION METHOD FOR M-ARY UNIDIRECTIONAL ERROR CONTROL CODES - APPLICATION FOR M-ARY BERGER CHECK TO ASYMMETRIC ERROR CONTROL CODES

Unidirectional error control codes have been studied extensively for application to VLSI memories. Also, studies on multiple-valued logic and memories received considerable attention since by employing multi-valued (m-ary) symbol representation, one can drastically reduce the interconnection area in VLSI chips as compared to the binary representation which requires more than 70% chip area for interconnection. In this context, m-ary unidirectional error control codes will be of great importance in improving reliability of such multiple-valued logic and memory systems. In this paper, we propose a new construction method for m-ary t-unidirectional error correcting and all-unidirectional error discriminating (t-UEC & all-UEDis)codes. We first show that a t-UEC & all-UEDis code can be characterized as a t-asymmetric error correcting (t-AEC) code with an added capability for discriminating errors between positive errors and negative errors. Noting this fact, we propose a simple construction method for t-UEC & all-UEDis codes starting from m-ary t-AEC codes.