Mobile data traffic offloading over Passpoint hotspots

Wi-Fi technology has always been an attractive solution for catering the increasing data demand inmobile networks because of the availability ofWi-Fi networks, the high bit rates they provide, and the lower cost of ownership. However, the legacyWiFi technology lacks of seamless interworking betweenWi-Fi and mobile cellular networks on the one hand, and between Wi-Fi hotspots on the other hand. Nowadays, the recently released Wi-Fi Certified Passpoint Program provides the necessary control-plane for these operations. Service providers can henceforth look to suchWi-Fi systems as a viable way to seamlessly offloadmobile traffic and deliver added-value services, so that subscribers no longer face the frustration and aggravation of connecting toWi-Fi hotspots. However, the technology being rather recent, we are not aware of public studies at the state of the art documenting the achievable gain in real mobile networks. In this paper, we evaluate the capacity and energy saving gain that one can get by offloading cellular data traffic over Passpoint hotspots as a function of different hotspot placement schemes and of access point selection policies (two enabled by the Passpoint controlplane and one independent of it). We compare the policies using real mobile data from the Orange network in Paris. We show that offloading using Passpoint control-plane information cangrantup to15%capacitygainand13%energy savinggainwith respect toPasspoint-agnostic ones based on signal quality information. As of placement strategy, installing Passpoint hotspots in the outer annulus of the macrocell coverage grants the maximum capacity gain. © 2015 Elsevier B.V. All rights reserved.