Minimal Ball-covering of the Unit Spheres in R~n

Considering the following problem: for a Banach space X with dimX=n,it has already known that the sphere of the unit ball of X can be covered by a ball-covering of n+1 closed balls not containing the origin in its interior,then what is its smallest radius? This article first proves that there exists a specific ball-covering with the smallest radius in R~n if a set {x_i}~m_(i=1) satisfying some given term,then presents a minimal ball-covering with arbitrary given r≥32 as its radius.