Low Delay Single Symbol Error Correction Codes Based on Reed Solomon Codes

Abstract

To avoid data corruption, error correction codes (ECCs) are widely used to protect memories. ECCs introduce a delay penalty in accessing the data as encoding or decoding has to be performed. This limits the use of ECCs in high-speed memories. This has led to the use of simple codes such as single error correction double error detection (SEC-DED) codes. However, as technology scales multiple cell upsets (MCUs) become more common and limit the use of SEC-DED codes unless they are combined with interleaving. A similar issue occurs in some types of memories like DRAM that are typically grouped in modules composed of several devices. In those modules, the protection against a device failure rather than isolated bit errors is also desirable. In those cases, one option is to use more advanced ECCs that can correct multiple bit errors. The main challenge is that those codes should minimize the delay and area penalty. Among the codes that have been considered for memory protection are Reed-Solomon (RS) codes. These codes are based on non-binary symbols and therefore can correct multiple bit errors. In this paper, single symbol error correction codes based on Reed-Solomon codes that can be implemented with low delay are proposed and evaluated. The results show that they can be implemented with a substantially lower delay than traditional single error correction RS codes.