On the distribution of inter contact time for DTNs

Inter contact time (ICT) between two mobile nodes is essential to forwarding algorithms and the end-to-end delay in Delay Tolerant Networks (DTNs). However, studies regarding the distribution of ICT lack general applicability and the exponential parameter concerns with too many motion characteristics. Consequently, it is difficult to design the protocol and analyze the performance for DTNs. In this paper, we demonstrate ICT between two mobile nodes is exponentially distributed and the exponential parameter relates to their historical contact numbers and the cumulative ICTs. Moreover, through extensive experimental simulations, we find that our findings have a general applicability in both theoretical mobility models and real world mobility traces, thus providing guidelines on the design of new mobility models with exponential distribution, new message protocols and further performance analysis methods.