Social-Energy-Aware User Clustering for Content Sharing Based on D2D Multicast Communications

With the ever-increasing demands for content sharing, device-to-device (D2D) multicast content sharing is becoming a promising technology to improve the quality of local area services. In order to guarantee the implementation of D2D multicast content sharing, the main concern is the user clustering, i.e., cluster head (CH) selection and cluster formation. Most of the existing works fail to design a distributed scheme with a concern of the incentive to stimulate cooperation. In this paper, we model a novel user clustering problem with the target of maximizing the energy efficiency of the D2D multicast network, where both the social tie information and the pricing scheme are adopted to stimulate cooperation. Due to its NP-hard property, it is decomposed into two subproblems. Specifically, a CH selection algorithm based on social maximum weight is first proposed to discriminate the proper CHs from multitudinous candidates and restrict the upper bound of the number of the selected CHs. After that, we model the cluster formation process as a non-transferable utility coalition formation game, and a distributed coalition formation algorithm for cluster formation is proposed based on preference relationship and switch operations. Importantly, the final coalition structure is proved to be Nash stable. Numerical results show that our proposed scheme outperforms other three baseline schemes.