On the Root Cause of Dropout-Induced Contraction Process in D2D-Based Mobile Social Networks
Sigit Aryo Pambudi, Wenye Wang, Cliff Wang · 2017
Device-to-device (D2D)-based mobile social networking (MSN) has been touted as a low-power, low-cost alternative to conventional MSN over cellular and WiFi networks. Nevertheless, the open nature of communication channels and the users' social activity that tend to decline over time expose D2D-based MSN to network contractions, which is a consequence of initial dropouts, combined with the jointly unsuccessful information delivery and social contacts. As a result, the network may found some of its users to vanish without knowing the cause of such dropouts. This, however, is a desirable knowledge that can guide towards the design of effective countermeasure schemes. In this paper, we study the problem of deciding whether initial dropouts are social or communication-induced, given the outcome of the network contractions. To do so, we define a minimum utility ratio that quantifies the worst-case impact of network contractions generated by initial dropouts. We derive self-consistent equations for computing the different minimum utility ratios caused by social and communication-based dropouts. We further show that this metric may exhibit different scaling order behaviors, depending on the root cause of initial dropouts. Finally, numerical results show that the proposed self-consistent equations and scaling order analysis can effectively distinguish social and communication-induced network contractions.