A new upper bound for error-correcting codes
Selmer Martin Johnson · IEEE Transactions on Information Theory · 1962
By refining Hamming's geometric sphere-packing model a new upper bound for nonsystematic binary error-correcting codes is found. Only combinatorial arguments are used. Whereas Hamming's upper bound estimate fore-error-correcting codes involved a count of all points\leq eHamming distance from the set of code points, the model is extended here to include consideration of points which are>edistance away from the code set. The percentage improvement from Hamming's bounds is sometimes quite sizable for cases of two or more errors to be corrected. The new bound improves on Wax's bounds in all but four of the cases he lists.