New SEC-DED-DAEC codes for multiple bit upsets mitigation in memory

Nowadays, multiple bit upsets (MBUs) have been widely investigated in memories. Conventional single error correction and double error detection (SEC-DED) codes are capable of correcting one error and detecting all possible double errors. However, they may not provide adequate protection against MBUs. This paper proposes new single-error-correction, double-error-detection double-adjacent-error-correction (SEC-DED-DAEC) codes to mitigate radiation or noise source induced MBUs in memories. The proposed SEC-DED-DAEC codes are obtained from conventional SEC-DED codes according to the mathematics model established in this paper. They can detect and correct all adjacent double bit errors and assure a lower miscorrection probability for non-adjacent double bit errors compared with other SEC-DED-DAEC codes. Furthermore, the redundancy bits of the proposed scheme are the same as those of conventional SEC-DED codes. This means that the increase of correct-capability do not cause additional hardware overhead for the memory system. Finally, the experiment results reveal that the proposed scheme reduces the miscorrection probability of non-adjacent double bit errors by 12% compared to the best known SEC-DED-DAEC codes. Moreover, compared to the well known BCH codes, the proposed scheme reduces 40% hardware redundancy and keeps an acceptable reliability.