Over the last few years, the number of mobile devices connected to the CERN internal network has increased from a handful in 2006 to more than 10,000 in 2015. Wireless access is no longer a “nice to have” or just for conference and meeting rooms, now support for mobility is expected by most, if not all, of the CERN community. In this context, a full renewal of the CERN Wi-Fi network has been launched in order to provide a state-of-the-art Campus-wide Wi-Fi Infrastructure. Which technologies can provide an end-user experience comparable, for most applications, to a wired connection? Which solution can cover more than 200 office buildings, which represent a total surface of more than 400.000 m2, while keeping a single, simple, flexible and open management platform? The presentation will focus on the studies and tests performed at CERN to address these issues, as well as some feedback about the global project organisation.