Online advertising and advancements is a recent trend in marketing technology, in this context we consider a new form of contract which allows advertisers to specify in the Wifi system. Based on the structure of the system, we have to organize and manage resource allocation such that the guaranteed display is satisfied. We introduce a new mathematical model and develop an optimization framework that aims to optimize “fairness” of allocation each campaign over its targeted location. Because of large scale problem, the Dantzig-Wolfe decomposition is proposed for solving it. Dantzig-Wolfe decomposition is a technique for dealing with large scale linear programming and modified to solve linear integer programming, nonlinear programming. Especially, it is used mostly in linear programming when its size is very large, and its structure is appropriate. The technique has been successfully applied in a variety of contexts. In this paper, we introduce a new model of a resource allocation problem in Wifi network and represent Dantzig-Wolfe decomposition for solving this problem by dividing the number of advertisement impressions when users access the Wifi network. The numerical simulation shows the efficiency of our proposed method.