WiFi Networks in Metropolises: From Access Point and User Perspectives

Although WiFi was initially designed for providing local access to the Internet, today's expansive and explosive deployment of WiFi networks has enabled nearly ubiquitous access for mobile users in many urban areas. However, these WiFi networks have been woefully undermeasured and underinstrumented during the wild expansion. We have closely collaborated with a leading network service provider to collect massive information about wireless APs and their users in four metropolises. In this article, based on the large-scale dataset, we attempt to answer the critical questions on how the APs are deployed and how they are utilized in urban areas. At the macro level, we depict the coverage of WiFi networks and the usage patterns, and by carefully classifying the APs, we unveil rich geographical features of today's urban WiFi networks. At the micro level, we identify the implicit social relationships among WiFi users, and uncover the underlying social communities that have great potential for network optimization.