The problem therefore was how do you find out E from received syndrome, because if you know E then one can find out what the code word transmitted was, by just adding it to R, because R plus E equals to C. All block codes by and large on this very principle. Many codes are available for error correction based on these principles. The basic issues are what is the amount of redundancy that you had, that is the value of R that is had; what is the minimum distance of the code and what is the decoding algorithm and how complex is a decoding algorithm. Hypothetically I would like to have minimum amount of redundancy to get maximum error correcting capability. That unfortunately is not true and therefore there are techniques which are available to give us error correcting capability of various others.

---