On delivery control for floating contents sharing with epidemic broadcasting

In this paper, we propose a delivery control method of floating contents called PFCS (Proportional control for Floating Content Sharing) and investigate its properties through stability analysis. By intentionally limiting the coverage and the lifetime of epidemic broadcasting, floating contents can be shared among mobile nodes without dedicated infrastructure. Information sharing with floating contents is realized by (1) embedding the usable area (i.e., anchor zone) and the lifetime (i.e., TTL (Time-to-Live)) in a message, (2) forwarding the message among mobile nodes only in its anchor zone, (3) deleting the message if it expires, and (4) deleting the message, if necessary, once the mobile node carrying the message leaves the anchor zone. Hence, if message forwarding among mobile nodes is discontinued or some messages are lost due to buffer overflow of a mobile node, floating contents may be vanished. Such a limitation becomes more problematic when the anchor zone accommodates a number of floating contents. In this paper, we therefore propose a delivery control method of floating contents called PFCS, which controls the message possession ratio (i.e., the fraction of mobile nodes carrying a message in the anchor zone). We also perform stability analysis of PFCS to investigate fundamental properties of PFCS. Through numerical examples and simulation results, we demonstrate the effectiveness of PFCS as well as the validity of our approximate analysis.