An asymptotic bound on the covering radii of binary BCH codes

P. Deligne's theorem (1974) is used to prove that the covering radius of a primitive binary BCH code with designed distance 2t+1 is equal to 2t-1 if t is of the form 2/sup u/+1 and the code length is at least (2t)/sup 4t-2/. It is believed that this is the first time Deligne's theorem is used on coding theory.<
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