Characterizing content sharing properties for mobile users in open city squares

For mobile delay-tolerant networks, different mobility models have been utilized to assess the performance of routing algorithms and applications. Substantial work has gone into understanding the contact characteristics of mobile users to allow evaluation under conditions that approximate the real world. One important finding has been recognizing that contacts humans make at a macroscopic level is derived from daily routines and social interactions so that analyzing social network structures can assist in determining, e.g., suitable peers for message forwarding. While mid- to long-term social interaction patterns assist in delivering messages at larger scales, such patterns become immaterial when considering a microscopic scale such as content sharing in a city square. At microscopic scales, we face an “open” simulation area in which nodes enter and leave rather than a closed system with a fixed set of nodes. Moreover, small scales show more dynamics (e.g., in terms of node density) and steady state analyses become insufficient. In this paper, we investigate the operation of a content sharing application, Floating Content, under such microscopic mobility conditions and characterize its behavior for city squares. For its validation, we derive a mobility model for open squares to which mobile nodes enter and from which they depart.