# User-Information-Aware D2D Multicast File Distribution Mechanism
## 2 Related Works
In [20], the notion of social-aware rate is proposed by combining the social selfishness with the link rate, which can ensure the physical link quality and effective collaboration between users, and then the problem of social-aware-rate-based file sharing mode selection is modeled as a maximum weight mixed matching problem. In order to eliminate the negative impacts of relay node's selfishness, the user's interest factor is considered into the establishment of D2D file sharing cluster in [21], the proposed cosine-similarity-based greedy intra-cluster caching scheme has achieved near-optimal delay performance. In [22], a trust-oriented partner selection mechanism (TPSM) is proposed, which canavoid choosing those users with non-cooperative behavior as cooperative users. With the consideration of user's psychological structure, the multi-dimensional trust relationships between sending users and cooperative users is built, including cognition, emotion, and behavior. In addition, the cooperative nodes are stimulated to actively participate in data distribution so as to further eliminate the negative impact of user selfishness. In [23], a Stackelberg game-based pricing mechanism is proposed to inspire the core users to assist in the distribution of videos. The proposed mechanism provides guarantees for the benefits of the system and the core users, improving the effectiveness and reliability of the system. Integrating social domain information into the traditional D2D multicast communication research method is closer the actual communication environment, further improving the D2D multicast communication performance. The relay nodes can consume a large amount of energy when forwarding data for other users, but the battery capacity of relay nodes is limited. Therefore, in the relevant research areas, besides the efforts to improve the data distribution rate, delay performance, and system capacity, there are a large number of domestic and international researches which devoted to optimizing the energy efficiency of the system [24; 25; 26]. To cope with the increasing demand for local services in 5G cellular networks, literature [27] proposed a new cellular communication architecture that integrates energy harvesting technology and social networking features into D2D communication for local data dissemination. The proposed architecture includes three domains: the physical domain, the energy domain, and the social domain, which enables a significant improvement in the spectrum efficiency and energy efficiency of localized data transmission. A joint power and resource allocations scheme is proposed in [28] with a goal of improving the energy efficiency, maximizing the number of accessed D2D groups, and minimizing the total terminal transmission power for D2D underlay multicast communication at the same time. In order to improve the performance of D2D multicast data distribution such as throughput, spectrum efficiency, and energy efficiency, the above studies have proposed their own solutions. Nonetheless, most videos are accessed by a large number of users at any time during the day, so the same videos in the same area are transmitted multiple times at different times by using existing D2D multicast communication technology, bring about a large amount of redundant transmissions. To tackle the aforementioned redundant transmission and improve the resource utilization efficiency of the D2D multicast communication system, this paper proposed a novel user-information-aware D2D multicast file distribution mechanism, in which the video is pushed to potential service requesters when distributing video for requesters. The throughput has been improved greatly by increasing the number of D2D multicast receivers, and in turn the energy efficiency and spectrum efficiency have been improved dramatically.