Minimum-cost gateway deployment in cellular Wi-Fi networks

With the standardization of IEEE 802.11, there has been an explosive growth of wireless local area networks (WLAN). Recently, this cost effective technology is being deployed aggressively for establishing the "cellular Wi-Fi" network, where a large number of access points (APs) are interconnected by wireless links, forming a metro-scale wireless mesh network in order to support ubiquitous Internet access in the urban area. This paper focuses on the optimization of cellular Wi-Fi. In particular, we aim at finding a set of gateways and their optimal placement so as to minimize the network installation costs while maintaining reliability, flexibility, and an acceptable grade of service. We propose two approaches in this research. The first approach is based on integer linear programming (ILP), where we developed a set of linear inequalities according to various constraints and find the solution of the ILP model by using lp-solve. The second approach is an OPEN/CLOSE heuristic, tailored for cellular Wi-Fi, which arrives at a sub-optimal solution. Extensive simulations are carried out for performance evaluation. Simulation results show that the proposed approaches can effectively identify a set of gateways at optimal locations in a cellular Wi-Fi network, resulting in an overall cost reduction of up to 50%.

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