1. A computer-implemented method comprising: determining, by a radio network controller, a ranking for each of a plurality of received objects using a plurality of similarity graphs for a plurality of base stations, wherein the plurality of received objects include data files received from at least one of the plurality of base stations, the ranking calculated by min f ∈  n 1 2 f T Lf + M ∑ i , j η i , j ∑ l ( ζ D il ∑ k D kl + D il ′ ∑ k D kl ′ ) W i C il - ( ζ D jl ∑ k D kl + D jl ′ ∑ k D kl ′ ) W j C jl subject to 
 f i −f j ≧1 −n ij ,   (1) 
 n ij ≧0∀i,j   (2) where each object I i has a bandwidth W i ; C il units of cost is associated with unit transfer of item I i from the radio network controller to base station B i ; there is a premium demand D′ il and a non-premium demand D il for I i at base station B i ; ζ>1 represents a weight assigned to the premium demand; n ij represents a corresponding Lagrangian coefficient L represents a Laplacian matrix of a graph; and M is a coefficient of a regularizer, which is introduced to avoid overfitting; extracting, by the radio network controller, a common structure by collaborative filtering data associated with a plurality of user devices and the plurality of received objects; analyzing, by the radio network controller, the common structure to infer usage patterns within a time slot; and storing, by the radio network controller, a subset of the ranked objects of the plurality of received objects in response to the analysis.