Scaling online collaborative games to urban level

With the growing availability of personal communication devices we are witnessing a tremendous increase in the demand for mobile services based on location and context. Mobile gaming is, of course, following this same trend. Unfortunately, differently from other services, location- and context-based gaming strictly requires near-field communication to interact with nearby players in order to create teams and arenas. Since currently adopted technologies suffer from scalability (Bluetooth) or energy (WiFi) constraints, Opportunistic Networks (ONs) have already been addressed as a viable solution to involve a considerable number of players on a wider area. While massive multiplayer games are commonplace on wired networks, it is not yet clear how player experience is affected by the increased delay and probabilistic message forwarding introduced by a huge population over an ON. In this paper we address this problem by proposing an opportunistic collaborative game, which is meaningful for the category of collaborative puzzle games, and evaluating its playability and scalability by means of simulations on a real city topology.