A detailed review of D2D cache in helper selection

With the rapid development of communication networks, the information interaction between heterogeneous networks such as the Internet of Things (IoT) and vehicle ad-hoc networks (VANETs) is becoming more and more common. In cellular networks, the proximity devices may share files directly without going through the eNBs, which is named Device-to-Device (D2D) communications. It has been considered as a potential technological component for the next generation of communication. The traditional centralized network architecture cannot accommodate such user demands due to heavy burden on the back-haul links and long latency. Cyber-social networks seamlessly integrate people’s daily lives and social activities, which has a prominent contribution to the social relationship of mobile users in D2D communication. In this paper, we make an exhaustive review on the state-of-the-art research efforts on D2D caching. We first give an overview of D2D helper selection, including the network frame, computing method, and social-aware attribute. Next, a comprehensive survey of issues on D2D helper selection is presented. Finally, open research challenges and future directions are presented as well.