A novel security-centric framework for D2D connectivity based on spatial and social proximity

Device-to-device (D2D) communication is one of the most promising innovations in the next-generation wireless ecosystem, which improves the degrees of spatial reuse and creates novel social opportunities for users in proximity. As standardization behind network-assisted D2D technology takes shape, it becomes clear that security of direct connectivity is one of the key concerns on the way to its ultimate user adoption. This is especially true when a personal user cluster (that is, a smartphone and associated wearable devices) does not have a reliable connection to the cellular infrastructure. In this paper, we propose a novel framework that embraces security of geographically proximate user clusters. More specifically, we employ game-theoretic mechanisms for appropriate user clustering taking into account both spatial and social notions of proximity. Further, our information security procedures implemented on top of this clustering scheme enable continuous support for secure direct communication even in case of unreliable/unavailable cellular connectivity. Explicitly incorporating the effects of user mobility, we numerically evaluate the proposed framework by confirming that it has the potential to substantially improve the resulting system-wide performance.